keratan-sulfate and Mucopolysaccharidosis-IV

Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase (

Topics: Animals; Chondrocytes; Chondroitin Sulfates; Chondroitinsulfatases; Disease Models, Animal; Humans; Keratan Sulfate; Mice; Mucopolysaccharidosis IV

Mucopolysaccharidosis type IVA (MPS IVA, or Morquio syndrome type A) is an inherited metabolic lysosomal disease caused by the deficiency of the N-acetylglucosamine-6-sulfate sulfatase enzyme. The deficiency of this enzyme accumulates the specific glycosaminoglycans (GAG), keratan sulfate, and chondroitin-6-sulfate mainly in bone, cartilage, and its extracellular matrix. GAG accumulation in these lesions leads to unique skeletal dysplasia in MPS IVA patients. Clinical, radiographic, and biochemical tests are needed to complete the diagnosis of MPS IVA since some clinical characteristics in MPS IVA are overlapped with other disorders. Early and accurate diagnosis is vital to optimizing patient management, which provides a better quality of life and prolonged life-time in MPS IVA patients. Currently, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are available for patients with MPS IVA. However, ERT and HSCT do not have enough impact on bone and cartilage lesions in patients with MPS IVA. Penetrating the deficient enzyme into an avascular lesion remains an unmet challenge, and several innovative therapies are under development in a preclinical study. In this review article, we comprehensively describe the current diagnosis, treatment, and management for MPS IVA. We also illustrate developing future therapies focused on the improvement of skeletal dysplasia in MPS IVA.

Topics: Bone and Bones; Cartilage; Chondroitin Sulfates; Disease Management; Early Diagnosis; Enzyme Replacement Therapy; Genetic Therapy; Glycosaminoglycans; Hematopoietic Stem Cell Transplantation; Humans; Keratan Sulfate; Lysosomes; Mucopolysaccharidosis III; Mucopolysaccharidosis IV; Nanomedicine; Osteochondrodysplasias; Quality of Life

Mucopolysaccharidosis IVA (MPS IVA, Morquio A syndrome) is an autosomal recessive disorder caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase. Deficiency of this enzyme leads to the accumulation of specific glycosaminoglycans (GAGs), chondroitin-6-sulfate (C6S) and keratan sulfate (KS), which are mainly synthesized in the cartilage. Therefore, the substrates are stored primarily in the cartilage and its extracellular matrix (ECM), leading to a direct impact on bone development and successive systemic skeletal spondylepiphyseal dysplasia. The skeletal-related symptoms for MPS IVA include short stature with short neck and trunk, odontoid hypoplasia, spinal cord compression, tracheal obstruction, obstructive airway, pectus carinatum, restrictive lung, kyphoscoliosis, platyspondyly, coxa valga, genu valgum, waddling gait, and laxity of joints. The degree of imbalance of growth in bone and other organs and tissues largely contributes to unique skeletal dysplasia and clinical severity. Diagnosis of MPS IVA needs clinical, radiographic, and laboratory testing to make a complete conclusion. To diagnose MPS IVA, total urinary GAG analysis which has been used is problematic since the values overlap with those in age-matched controls. Currently, urinary and blood KS and C6S, the enzyme activity of GALNS, and GALNS molecular analysis are used for diagnosis and prognosis of clinical phenotype in MPS IVA. MPS IVA can be diagnosed with unique characters although this disorder relates closely to other disorders in some characteristics. In this review article, we comprehensively describe clinical, radiographic, biochemical, and molecular diagnosis and clinical assessment tests for MPS IVA. We also compare MPS IVA to other closely related disorders to differentiate MPS IVA. Overall, imbalance of growth in MPS IVA patients underlies unique skeletal manifestations leading to a critical indicator for diagnosis.

Topics: Cartilage; Chondroitin Sulfates; Chondroitinsulfatases; Enzyme Replacement Therapy; Glycosaminoglycans; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Phenotype; Prognosis

Elosulfase alfa (Vimizim(®)) is a recombinant form of the human lysosomal enzyme N-acetylgalactosamine-6-sulfatase (GALNS) that is lacking in patients with mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome). It is the first, and currently only, disease-specific treatment option for this very rare, progressively degenerative, autosomal-recessive lysosomal storage disorder. Enzyme replacement therapy with elosulfase alfa aims to restore GALNS activity, thereby preventing the accumulation of keratan sulfate (KS) and chondroitin-6-sulfate in lysosomal compartments of cells that results in the clinical manifestations of MPS IVA. In clinical trials in children and adults with MPS IVA, intravenous elosulfase alfa 2 mg/kg/week provided significant and sustained improvements in urinary levels of KS (a pharmacodynamic biomarker for the disease). In the key placebo-controlled, 24-week, phase 3 trial in patients with MPS IVA aged ≥5 years, elosulfase alfa 2 mg/kg/week significantly improved endurance [least squares mean placebo-adjusted change from baseline in 6-min walk test distance 22.5 m (95 % CI 4.0-40.9)]. Infusion-associated reactions, the primary tolerability issue associated with elosulfase alfa, are generally mild to moderate in severity, self-limiting, and manageable. In the absence of a cure, GALNS enzyme replacement therapy with elosulfase alfa is an important achievement in the treatment of MPS IVA.

Topics: Chondroitin Sulfates; Chondroitinsulfatases; Clinical Trials as Topic; Dose-Response Relationship, Drug; Enzyme Replacement Therapy; Humans; Keratan Sulfate; Lysosomes; Mucopolysaccharidosis IV

G(M1)-gangliosidosis and Morquio B are rare lysosomal storage diseases associated with a neurodegenerative disorder or dwarfism and skeletal abnormalities, respectively. These diseases are caused by deficiencies in the lysosomal enzyme human β-D-galactosidase (h-β-GAL), which lead to accumulations of the h-β-GAL substrates, G(M1) ganglioside and keratan sulfate due to mutations in the h-β-GAL gene. H-β-GAL is an exoglycosidase that catalyzes the hydrolysis of terminal β-linked galactose residues. Here, we present the crystal structures of h-β-GAL in complex with its catalytic product galactose or with its inhibitor 1-deoxygalactonojirimycin. H-β-GAL showed a novel homodimer structure; each monomer was comprised of a catalytic TIM barrel domain followed by β-domain 1 and β-domain 2. The long loop region connecting the TIM barrel domain with β-domain 1 was responsible for the dimerization. To gain structural insight into the molecular defects of h-β-GAL in the above diseases, the disease-causing mutations were mapped onto the three-dimensional structure. Finally, the possible causes of the diseases are discussed.

Topics: Animals; beta-Galactosidase; Gangliosides; Gangliosidosis, GM1; Humans; Keratan Sulfate; Lysosomal Storage Diseases; Lysosomes; Molecular Conformation; Mucopolysaccharidosis IV; Mutation; Protein Structure, Tertiary; Substrate Specificity

Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio A, is a rare, autosomal recessive disorder caused by a deficiency of the lysosomal enzyme N-acetylgalatosamine-6-sulfate-sulfatase (GALNS), which catalyzes a step in the catabolism of glycosaminoglycans (GAGs), keratan sulfate (KS) and chondroitin-6-sulfate (C6S). It leads to accumulation of the KS and C6S, mainly in bone and cornea, causing a systemic skeletal chondrodysplasia. MPS IVA has a variable age of onset and variable rate of progression. Common presenting features include elevation of urinary and blood KS, marked short stature, hypoplasia of the odontoid process, pectus carinatum, kyphoscoliosis, genu valgum, laxity of joints and corneal clouding; however there is no central nervous system impairment. Generally, MPS IVA patients with a severe form do not survive beyond the third decade of life whereas those patients with an attenuated form may survive over 70 years. There has been no effective therapy for MPS IVA, and care has been palliative. Enzyme replacement therapy (ERT) and hematopoietic stem cell therapy (HSCT) have emerged as a treatment for mucopolysaccharidoses disorders, including Morquio A disease. This review provides an overview of the clinical manifestations, diagnosis and symptomatic management of patients with MPS IVA and describes potential perspectives of ERT and HSCT. The issue of treating very young patients is also discussed.

Topics: Animals; Enzyme Replacement Therapy; Hematopoietic Stem Cell Transplantation; Humans; Keratan Sulfate; Mucopolysaccharidosis IV

Topics: beta-Galactosidase; Biomarkers; Diagnosis, Differential; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Mutation; Prognosis

Topics: Age of Onset; beta-Galactosidase; Bone Diseases, Developmental; Bone Marrow Examination; Diagnosis, Differential; Facial Bones; Female; Gangliosidosis, GM1; Glycosaminoglycans; Humans; Infant; Keratan Sulfate; Kyphosis; Leukocytes; Mucolipidoses; Mucopolysaccharidosis I; Mucopolysaccharidosis IV; Odontoid Process; Pedigree; Scoliosis

Efficacy and safety of elosulfase alfa enzyme replacement therapy (ERT) were assessed in an open-label, phase 2, multi-national study in Morquio A patients aged ≥5 years unable to walk ≥30 meters in the 6-min walk test. Patients received elosulfase alfa 2.0 mg/kg/week intravenously for 48 weeks. Efficacy measures were functional dexterity, pinch/grip strength, mobility in a modified timed 25-foot walk, pain, quality of life, respiratory function, and urine keratan sulfate (KS). Safety/tolerability was also assessed. Fifteen patients received elosulfase alfa, three patients discontinued ERT due to adverse events (two were grade 3 drug-related adverse events, the other was not drug-related), and two patients missed >20% of planned infusions; 10 completed treatment through 48 weeks and received ≥80% of planned infusions (Modified Per Protocol [MPP] population). The study population had more advanced disease than that enrolled in other trials. From baseline to week 48, MPP data showed biochemical efficacy (urine KS decreased 52.4%). The remaining efficacy results were highly variable due to challenges in test execution because of severe skeletal and joint abnormalities, small sample sizes, and clinical heterogeneity among patients. Eight patients showed improvements in one or more outcome measures; several patients indicated improvements not captured by the study assessments (e.g., increased energy, functional ability). The nature of adverse events was similar to other elosulfase alfa studies. This study illustrates the considerable challenges in objectively measuring impact of ERT in very disabled Morquio A patients and highlights the need to examine results on an individual basis. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Topics: Activities of Daily Living; Adolescent; Adult; Biomarkers; Child; Chondroitinsulfatases; Enzyme Replacement Therapy; Exercise; Female; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Quality of Life; Respiratory Function Tests; Self Report; Treatment Outcome; Walking; Young Adult

Elosulfase alfa is an enzyme replacement therapy for the treatment of Morquio A syndrome (mucopolysaccharidosis IVA), a lysosomal storage disorder caused by a deficiency of the enzyme N-acetylgalactose-amine-6-sulfatase. We previously reported immunogenicity data from our 24-week placebo-controlled Phase III study, MOR-004. Here, we report the long-term immunogenicity profile of elosulfase alfa from MOR-005, the Phase III extension trial to assess potential correlations between antidrug antibodies and efficacy and safety profile outcomes throughout 120 weeks of treatment.. The long-term immunogenicity of elosulfase alfa was evaluated in patients with Morquio A syndrome in an open-label extension study for a total of 120 weeks. All patients received 2.0 mg/kg elosulfase alfa either weekly or every other week before establishment of 2.0 mg/kg/wk as the recommended dose, at which time all patients received weekly treatment. Efficacy measures were compared with those from the MOR-004 baseline, enabling analysis of changes over 120 weeks. The primary efficacy measure was the change from baseline in 6-minute walk test. Secondary measures included changes from baseline in 3-minute stair climb test and normalized urine keratan sulfate, a pharmacodynamic metric.. All patients treated with elosulfase alfa developed antidrug total antibodies (TAb) by week 24 of MOR-004. In the extension study, all patients, including those who had previously received placebo, were TAb positive by study week 36 (MOR-005 week 12). All patients remained TAb positive throughout the study, and TAb titers were similar across treatment groups at week 120. Nearly all patients tested positive for neutralizing antibodies (NAb) at least once, with incidence of NAb positivity peaking at 85.9% at study week 36, then steadily declining to 66.0% at study week 120. In all treatment groups, mean urine keratan sulfate remained below treatment-naive baseline despite the presence of antidrug antibodies. No relationship was observed between TAb titers or NAb positivity and changes in urine keratan sulfate, 6-minute walk test, or 3-minute stair climb test from baseline to week 120. No consistent associations were detected between antidrug antibodies and the occurrence of hypersensitivity adverse events or anaphylaxis over the course of the study.. Immunogenicity results from this long-term study are consistent with previously reported 24-week results. Despite the sustained presence of antidrug antibodies, elosulfase alfa was well tolerated, and patients continued to benefit from treatment through week 120. No associations were detected between higher TAb titers or NAb positivity and reduced treatment effect or worsened safety profile measures. ClinicalTrials.gov identifier: NCT01415427.

Topics: Adult; Antibodies, Neutralizing; Child; Chondroitinsulfatases; Double-Blind Method; Enzyme Replacement Therapy; Female; Humans; Keratan Sulfate; Male; Middle Aged; Motor Activity; Mucopolysaccharidosis IV

Long-term efficacy and safety of elosulfase alfa enzyme replacement therapy were evaluated in Morquio A patients over 96weeks (reaching 120weeks in total from pre-treatment baseline) in an open-label, multi-center, phase III extension study. During this extension of a 24-week placebo-controlled phase III study, all patients initially received 2.0mg/kg elosulfase alfa either weekly or every other week, prior to establishment of 2.0mg/kg/week as the recommended dose, at which point all patients received weekly treatment. Efficacy measures were compared to baseline of the initial 24-week study, enabling analyses of changes over 120weeks. In addition to performing analyses for the entire intent-to-treat (ITT) population (N=173), analyses were also performed for a modified per-protocol (MPP) population (N=124), which excluded patients who had orthopedic surgery during the extension study or were non-compliant with the study protocol (as determined by ≥20% missed infusions). Six-minute walk test (6MWT) was the primary efficacy measure; three-minute stair climb test (3MSCT) and normalized urine keratan sulfate (uKS) were secondary efficacy measures. Mean (SE) change from baseline to Week 120 in 6MWT distance was 32.0 (11.3)m and 39.9 (10.1)m for patients receiving elosulfase alfa at 2.0mg/kg/week throughout the study (N=56) and 15.1 (7.1)m and 31.7 (6.8)m in all patients combined, regardless of dosing regimen, for the ITT and MPP populations, respectively. Further analyses revealed that durability of 6MWT improvements was not impacted by baseline 6MWT distance, use of a walking aid, or age. Mean (SE) change at Week 120 in the 3MSCT was 5.5 (1.9) and 6.7 (2.0)stairs/min for patients receiving elosulfase alfa at 2.0mg/kg/week throughout the study and 4.3 (1.2) and 6.8 (1.3)stairs/min in all patients combined, regardless of dosing regimen, for the ITT and MPP populations, respectively Across all patients, mean (SE) change at Week 120 in normalized uKS was -59.4 (1.8)% and -62.3 (1.8)% in the ITT and MPP populations, respectively. In the absence of a placebo group, significance of the sustained improvements could not be evaluated directly. However, to provide context for interpretation of results, comparisons were performed with untreated patients from a Morquio A natural history study. In contrast to the results of the extension study, the untreated patients experienced constant uKS levels and a gradual decline in endurance test results over a similar period of tim

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Chondroitinsulfatases; Double-Blind Method; Enzyme Replacement Therapy; Female; Humans; Keratan Sulfate; Male; Middle Aged; Mucopolysaccharidosis IV; Physical Endurance; Young Adult

Morquio A syndrome (mucopolysaccharidosis IVA [MPS IVA]) is a lysosomal storage disorder caused by deficiency of the enzyme N-acetylgalactosamine-6-sulfatase, which is required to degrade the glycosaminoglycan keratan sulfate. Morquio A is associated with extensive morbidity and early mortality. Elosulfase alfa is an enzyme replacement therapy that provides a treatment option for patients with Morquio A. We examined the immunogenicity profile of elosulfase alfa, assessing any correlations between antidrug antibodies and the efficacy and safety outcomes in 176 patients with Morquio A from a 24-week international Phase III trial.. Patients were randomized to placebo (n = 59) or elosulfase alfa 2.0 mg/kg administered weekly (n = 58) or every other week (n = 59) as an ~4-hour infusion. Blood samples were routinely tested to determine drug-specific total antibody titer and neutralizing antibody (NAb) positivity. Drug-specific immunoglobulin E positivity was tested routinely and in response to severe hypersensitivity adverse events (AEs). Antidrug antibody positivity and titer were compared with efficacy and safety metrics to assess possible correlations.. The 176 patients in the trial were 54% female, with a mean age of 11.9 years. In all patients treated with elosulfase alfa antidrug antibodies developed, and in the majority, antibodies capable of interfering with cation-independent mannose-6-phosphate receptor binding in vitro (NAb) developed. Less than 10% of patients tested positive for drug-specific IgE during the study. Despite the high incidence of anti-elosulfase alfa antibodies, no correlations were detected between higher total antibody titers or NAb positivity and worsened 6-minute walk test results, urine keratin sulfate levels, or hypersensitivity AEs. Drug-specific IgE positivity had no apparent association with the occurrence of anaphylaxis, other hypersensitivity AEs, and/or treatment withdrawal.. Despite the universal development of antidrug antibodies, elosulfase alfa treatment was both safe and well tolerated and immunogenicity was not associated with reduced treatment effect. ClinicalTrials.gov identifier: NCT01275066. (Clin Ther.

Topics: Antibodies, Neutralizing; Child; Child, Preschool; Chondroitinsulfatases; Double-Blind Method; Drug Administration Schedule; Drug Hypersensitivity; Enzyme Replacement Therapy; Female; Humans; Immunoglobulin E; Keratan Sulfate; Male; Middle Aged; Mucopolysaccharidosis IV; Recombinant Proteins

The primary treatment outcomes of a phase 2, randomized, double-blind, pilot study evaluating safety, physiological, and pharmacological effects of elosulfase alfa in patients with Morquio A syndrome are herewith presented. Patients aged ≥7 years and able to walk ≥200 m in the 6-min walk test (6MWT) were randomized to elosulfase alfa 2.0 or 4.0 mg/kg/week for 27 weeks. The primary objective was to evaluate the safety of both doses. Secondary objectives were to evaluate effects on endurance (6MWT and 3-min stair climb test [3MSCT]), exercise capacity (cardio-pulmonary exercise test [CPET]), respiratory function, muscle strength, cardiac function, pain, and urine keratan sulfate (uKS) levels, and to determine pharmacokinetic parameters. Twenty-five patients were enrolled (15 randomized to 2.0 mg/kg/week and 10 to 4.0 mg/kg/week). No new or unexpected safety signals were observed. After 24 weeks, there were no improvements versus baseline in the 6MWT, yet numerical improvements were seen in the 3MSCT with 4.0 mg/kg/week. uKS and pharmacokinetic data suggested no linear relationship over the 2.0-4.0 mg/kg dose range. Overall, an abnormal exercise capacity (evaluated in 10 and 5 patients in the 2.0 and 4.0 mg/kg/week groups, respectively), impaired muscle strength, and considerable pain were observed at baseline, and there were trends towards improvements in all domains after treatment. In conclusion, preliminary data of this small study in a Morquio A population with relatively good endurance confirmed the acceptable safety profile of elosulfase alfa and showed a trend of increased exercise capacity and muscle strength and decreased pain.

Topics: Adolescent; Adult; Child; Chondroitinsulfatases; Double-Blind Method; Drug Administration Schedule; Enzyme Replacement Therapy; Exercise Test; Female; Heart Function Tests; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Muscle Strength; Patient Safety; Pilot Projects; Recombinant Proteins; Respiratory Function Tests; Treatment Outcome; Walking

Previous studies have shown that elosulfase alfa has a favorable efficacy/safety profile in Morquio A patients aged ≥5 y. This study evaluated safety and impact on urine keratan sulfate (uKS) levels and growth velocity in younger patients.. Fifteen Morquio A patients aged <5 y received elosulfase alfa 2.0 mg/kg/week for 52 wk during the primary treatment phase of a phase II, open-label, multinational study. Primary endpoint was safety and tolerability; secondary endpoints were change in uKS and growth velocity over 52 wk.. All 15 patients completed the primary treatment phase. Six of 743 infusions (0.8%) administered led to adverse events (AEs) requiring infusion interruption and medical intervention. Eleven patients (73.3%) had ≥1 study drug-related AE, mostly infusion-associated reactions. Mean z-score growth rate per year numerically improved from -0.6 at baseline to -0.4 at week 52. Comparison to untreated subjects of similar age in the Morquio A Clinical Assessment Program study showed a smaller decrease in height z-scores for treated than for untreated patients. Mean percent change from baseline in uKS was -30.2% at 2 wk and -43.5% at 52 wk.. Early intervention with elosulfase alfa is well-tolerated and produces a decrease in uKS and a trend toward improvement in growth.

Topics: Age Factors; Biomarkers; Body Height; Child Development; Child, Preschool; Chondroitinsulfatases; Drug Administration Schedule; Early Medical Intervention; Enzyme Replacement Therapy; Europe; Female; Humans; Infant; Infusions, Intravenous; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Recombinant Proteins; Time Factors; Treatment Outcome; United Kingdom

To assess the efficacy and safety of enzyme replacement therapy (ERT) with BMN 110 (elosulfase alfa) in patients with Morquio A syndrome (mucopolysaccharidosis IVA).. Patients with Morquio A aged ≥5 years (N = 176) were randomised (1:1:1) to receive elosulfase alfa 2.0 mg/kg/every other week (qow), elosulfase alfa 2.0 mg/kg/week (weekly) or placebo for 24 weeks in this phase 3, double-blind, randomised study. The primary efficacy measure was 6-min walk test (6MWT) distance. Secondary efficacy measures were 3-min stair climb test (3MSCT) followed by change in urine keratan sulfate (KS). Various exploratory measures included respiratory function tests. Patient safety was also evaluated.. At week 24, the estimated mean effect on the 6MWT versus placebo was 22.5 m (95 % CI 4.0, 40.9; P = 0.017) for weekly and 0.5 m (95 % CI -17.8, 18.9; P = 0.954) for qow. The estimated mean effect on 3MSCT was 1.1 stairs/min (95 % CI -2.1, 4.4; P = 0.494) for weekly and -0.5 stairs/min (95 % CI -3.7, 2.8; P = 0.778) for qow. Normalised urine KS was reduced at 24 weeks in both regimens. In the weekly dose group, 22.4 % of patients had adverse events leading to an infusion interruption/discontinuation requiring medical intervention (only 1.3 % of all infusions in this group) over 6 months. No adverse events led to permanent treatment discontinuation.. Elosulfase alfa improved endurance as measured by the 6MWT in the weekly but not qow dose group, did not improve endurance on the 3MSCT, reduced urine KS, and had an acceptable safety profile.

Topics: Adolescent; Adult; Child; Child, Preschool; Chondroitinsulfatases; Double-Blind Method; Enzyme Replacement Therapy; Female; Humans; Keratan Sulfate; Male; Middle Aged; Motor Activity; Mucopolysaccharidosis IV; Rare Diseases; Treatment Outcome; Walking; Young Adult

Mucopolysaccharidosis IVA (MPS IVA, Morquio A syndrome) is an inherited lysosomal storage disease caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), an enzyme required for stepwise degradation of keratan sulfate (KS). We have developed a selective, sensitive, accurate and precise LC-MS/MS assay for the KS-derived disaccharides Galβ1-4GlcNAc(6S) and Gal(6S)β1-4GlcNAc(6S) in human urine and plasma using keratanase II digestion.. Mean accuracy was 96-106% in urine and 97-108% in plasma. Precision was high, with relative standard deviations of 1-2% (intra-day) and 2-5% (inter-day) in urine and 1-2% (intra-day) and 4-7% (inter-day) in plasma. The lower limit of quantitation was 0.026 µg/ml (plasma) and 0.104 µg/ml (urine), with a quantitation range of 0.026-5 µg/ml (plasma) and 0.104-20 µg/ml (urine).. Clinical sample analysis in 168 MPS IVA patients and 225 healthy controls demonstrates the clinical utility of this method.

Topics: Adolescent; Adult; Biomarkers; Child; Child, Preschool; Chromatography, Liquid; Disaccharides; Female; Humans; Infant; Infant, Newborn; Keratan Sulfate; Male; Mass Spectrometry; Middle Aged; Mucopolysaccharidosis IV

Mucopolysaccharidosis IVA (MPS IVA) is a lysosomal storage disorder (LSD) caused by mutations in gene encoding for GALNS enzyme. Lack of GALNS activity leads to the accumulation of glycosaminoglycans (GAGs) keratan sulfate and chondroitin 6-sulfate. Although enzyme replacement therapy has been approved since 2014 for MPS IVA, still there is an unmet medical need to have improved therapies for this disorder. CRISPR/Cas9-based gene therapy has been tested for several LSDs with encouraging findings, but to date it has not been assayed on MPS IVA. In this work, we validated for the first time the use of CRISPR/Cas9, using a Cas9 nickase, for the knock-in of an expression cassette containing GALNS cDNA in an in vitro model of MPS IVA. The results showed the successful homologous recombination of the expression cassette into the AAVS1 locus, as well as a long-term increase in GALNS activity reaching up to 40% of wild-type levels. We also observed normalization of lysosomal mass, total GAGs, and oxidative stress, which are some of the major findings regarding the pathophysiological events in MPS IVA. These results represent a proof-of-concept of the use of CRISPR/Cas9 nickase strategy for the development of a novel therapeutic alternative for MPS IVA.

Topics: Chondroitinsulfatases; CRISPR-Cas Systems; Gene Editing; Glycosaminoglycans; Humans; Keratan Sulfate; Mucopolysaccharidosis IV

Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is caused by a deficiency of the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) enzyme, leading to the accumulation of glycosaminoglycans (GAG), keratan sulfate (KS) and chondroitin-6-sulfate (C6S), mainly in cartilage and bone. This lysosomal storage disorder (LSD) is characterized by severe systemic skeletal dysplasia. To this date, none of the treatment options for the MPS IVA patients correct bone pathology. Enzyme replacement therapy with elosulfase alpha provides a limited impact on bone growth and skeletal lesions in MPS IVA patients. To improve bone pathology, we propose a novel gene therapy with a small peptide as a growth-promoting agent for MPS IVA. A small molecule in this peptide family has been found to exert biological actions over the cardiovascular system. This work shows that an AAV vector expressing a C-type natriuretic (CNP) peptide induces bone growth in the MPS IVA mouse model. Histopathological analysis showed the induction of chondrocyte proliferation. CNP peptide also changed the pattern of GAG levels in bone and liver. These results suggest the potential for CNP peptide to be used as a treatment in MPS IVA patients.

Topics: Animals; Bone Development; Cartilage; Glycosaminoglycans; Keratan Sulfate; Mice; Mucopolysaccharidosis IV

Morquio disease, also called mucopolysaccharidosis IV (MPS IV), belongs to the group of lysosomal storage diseases (LSD). Due to deficiencies in the activities of galactose-6-sulfate sulfatase (in type A) or β-galactosidase (in type B), arising from mutations in

Topics: Apoptosis; Chondroitinsulfatases; Fibroblasts; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Staurosporine

Mucopolysaccharidosis type IVA (MPS IVA; Morquio syndrome type A) is an autosomal recessive disorder caused by defects in the lysosomal hydrolase N-acetylgalactosamine-6-sulfatase (GALNS) gene, leading to progressive systemic skeletal dysplasia. Early diagnosis and early intervention with enzyme replacement therapy are crucial for improving outcomes in these patients. However, a relatively high number of patients are genetically undiagnosed due to high allelic heterogeneity and the absence of robust functional evidence for most variants of the GALNS gene. Herein, we report a novel intronic variant identified with RNA analysis and an allele dropout (ADO) event caused by a common benign variant in the primer-binding site in a Korean boy with MPS IVA. A 28-month-old boy presented with pectus carinatum, kyphoscoliosis, and joint hypermobility with multiple skeletal dysplasia involving the vertebrae and hip joint. Total urinary glycosaminoglycans were elevated with a predominant keratan sulfate fraction, and GALNS (EC 3.1.6.4) activity was significantly decreased in leukocytes. Sanger sequencing was performed; however, only one heterozygous intronic variant with uncertain clinical significance, c.566+3A > T (p.(?)), was identified. As the patient exhibited clinical and biochemical features of MPS IVA, we conducted whole genome sequencing (WGS) of the patient and his family to clarify the molecular diagnosis. WGS revealed a compound heterozygous genotype, c.1019G > A (p.(Gly340Asp)) and c.566+3A > T (p.(?)), in the GALNS gene. On mRNA sequencing, c.566+3A > T, was confirmed to cause exon 5 skipping and a premature stop codon. With subsequent investigation, we discovered that the variant, c.1019G > A, was undetected on initial sequencing because of ADO due to a common benign variant (rs3859024:G > C) at the primer annealing location. We present a novel intronic variant with a splicing defect in the GALNS gene and suggest that clinicians review primer sequences in cases not diagnosed on Sanger sequencing before progressing to diagnostic steps such as WGS.

Topics: Acetylgalactosamine; Child, Preschool; Chondroitinsulfatases; Codon, Nonsense; Glycosaminoglycans; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV

Topics: Acetylgalactosamine; Carbon Isotopes; Keratan Sulfate; Mass Spectrometry; Molecular Diagnostic Techniques; Mucopolysaccharidosis IV

Mucopolysaccharidosis type IVA, also known as Morquio (Morquio-Brailsford) syndrome results from accumulation of keratan sulfate (KS) and chondroitin-6-sulfate (C6S), whereas the primary cause is mutations in the gene encoding galactosamine (N-acetyl)-6-sulfatase (GALNS). Phenotypically it seems to be a well-defined condition, with two main clinical forms: mild (attenuated) and severe, which are determined based on a combination of symptoms, i.e., enzymatic activity of GALNS, age of onset, and symptom severity. Nevertheless, the natural history of MPSIVA in relation to specific anthropometric parameters (growth, head circumference, body proportions, and face phenotype) is not precisely characterized. The aim of our work was to analyze the aforementioned anthropometric parameters, including correlation to molecular data (causative GALNS mutations).

Topics: Adolescent; Adult; Anthropometry; Child; Child, Preschool; Chondroitin Sulfates; Chondroitinsulfatases; Europe; Female; Genotype; Humans; Infant; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Mutation; Phenotype; Young Adult

To explore the correlation between glycosaminoglycan (GAG) levels and mucopolysaccharidosis (MPS) type, we have evaluated the GAG levels in blood of MPS II, III, IVA, and IVB and urine of MPS IVA, IVB, and VI by tandem mass spectrometry. Dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS; mono-sulfated KS, di-sulfated KS), and the ratio of di-sulfated KS in total KS were measured. Patients with untreated MPS II had higher levels of DS and HS in blood while untreated MPS III had higher levels of HS in blood than age-matched controls. Untreated MPS IVA had higher levels of KS in blood and urine than age-matched controls. The ratio of blood di-sulfated KS/total KS in untreated MPS IVA was constant and higher than that in controls for children up to 10 years of age. The ratio of urine di-sulfated KS/total KS in untreated MPS IVA was also higher than that in age-matched controls, but the ratio in untreated MPS IVB was lower than controls. ERT reduced blood DS and HS in MPS II, and urine KS in MPS IVA patients, although GAGs levels remained higher than the observed in age-matched controls. ERT did not change blood KS levels in MPS IVA. MPS VI under ERT still had an elevation of urine DS level compared to age-matched controls. There was a positive correlation between blood and urine KS in untreated MPS IVA patients but not in MPS IVA patients treated with ERT. Blood and urine KS levels were secondarily elevated in MPS II and VI, respectively. Overall, measurement of GAG levels in blood and urine is useful for diagnosis of MPS, while urine KS is not a useful biomarker for monitoring therapeutic efficacy in MPS IVA.

Topics: Adolescent; Adult; Biomarkers; Child; Child, Preschool; Dermatan Sulfate; Female; Glycosaminoglycans; Heparitin Sulfate; Humans; Keratan Sulfate; Male; Mucopolysaccharidoses; Mucopolysaccharidosis II; Mucopolysaccharidosis III; Mucopolysaccharidosis IV; Mucopolysaccharidosis VI; Tandem Mass Spectrometry; Young Adult

Since 2014, enzyme replacement therapy (ERT) has been available for treatment of Morquio A syndrome. During clinical trials, urinary keratan sulfate (KS) has been a useful biomarker and showed a marked decrease in patients on ERT, demonstrating therapy efficacy. Unfortunately, quantitative urinary KS testing is not widely available in biochemical genetics laboratories for efficient monitoring and follow-up of treated patients.. A tandem mass spectrometry methodology was devised to analyze KS disaccharides and creatinine in urine specimens collected on filter paper.. All Morquio A patients presented abnormal results pretreatment compared with reference values.. This collection procedure can be performed by patients at home and filter papers sent by regular mail to a specialized laboratory, facilitating follow-up of patients.

Topics: Adolescent; Adult; Biomarkers; Child; Child, Preschool; Chromatography, High Pressure Liquid; Creatinine; Enzyme Replacement Therapy; Follow-Up Studies; Humans; Keratan Sulfate; Limit of Detection; Male; Mucopolysaccharidosis IV; Paper; Reference Values; Tandem Mass Spectrometry; Urine Specimen Collection; Young Adult

Glycosaminoglycan analysis for the diagnosis of Morquio patients has been daunting due to lack of sensitivity/specificity of the dimethylmethylene blue-based spectrophotometry methodology, routinely used by several clinical laboratories. MS methods have been devised for quantification of keratan sulfate for Morquio patients, but some used tributylamine in mobile phases, or did not use isotope-labeled internal standards. Results & methodology: An UPLC-MS/MS methodology aiming to solve these issues was devised, based on the digestion of keratan sulfate to obtain two major disaccharides. Abnormal urinary results were obtained for all Morquio A patients, while the dimethylmethylene blue-based spectrophotometry methodology showed normal results for four out of nine cases.. The devised method is sensitive, specific and suitable for high-risk screening and longitudinal evaluation of treated patients.

Topics: Adolescent; Adult; Age Factors; Child; Child, Preschool; Chromatography, High Pressure Liquid; Female; Follow-Up Studies; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Reference Values; Tandem Mass Spectrometry; Urinalysis; Young Adult

We treated mucopolysaccharidosis IVA (MPS IVA) mice to assess the effects of long-term enzyme replacement therapy (ERT) initiated at birth, since adult mice treated by ERT showed little improvement in bone pathology [1]. To conduct ERT in newborn mice, we used recombinant human N-acetylgalactosamine-6-sulfate sulfatase (GALNS) produced in a CHO cell line. First, to observe the tissue distribution pattern, a dose of 250units/g body weight was administered intravenously in MPS IVA mice at day 2 or 3. The infused enzyme was primarily recovered in the liver and spleen, with detectable activity in the bone and brain. Second, newborn ERT was conducted after a tissue distribution study. The first injection of newborn ERT was performed intravenously, the second to fourth weekly injections were intraperitoneal, and the remaining injections from 5th to 14th weeks were intravenous into the tail vein. MPS IVA mice treated with GALNS showed clearance of lysosomal storage in the liver and spleen, and sinus lining cells in bone marrow. The column structure of the growth plate was organized better than that in adult mice treated with ERT; however, hyaline and fibrous cartilage cells in the femur, spine, ligaments, discs, synovium, and periosteum still had storage materials to some extent. Heart valves were refractory to the treatment. Levels of serum keratan sulfate were kept normal in newborn ERT mice. In conclusion, the enzyme, which enters the cartilage before the cartilage cell layer becomes mature, prevents disorganization of column structure. Early treatment from birth leads to partial remission of bone pathology in MPS IVA mice.

Topics: Administration, Intravenous; Animals; Animals, Newborn; Bone Diseases; Cartilage; CHO Cells; Chondrocytes; Chondroitinsulfatases; Cricetulus; Disease Models, Animal; Enzyme Replacement Therapy; Growth Plate; Keratan Sulfate; Liver; Mice; Mice, Knockout; Mucopolysaccharidosis IV; Recombinant Proteins; Spleen; Tissue Distribution

Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) is an autosomal recessive lysosomal storage disorder caused by deficient N-acetylgalactosamine-6-sulphatase (GALNS) activity. Early and accurate diagnosis of this condition is critical for improved patient outcomes, particularly as enzyme replacement therapy has recently become available. An LC-MS/MS assay utilising keratan sulphate (KS) disaccharides derived from keratanase-II digestion provides a sensitive and specific means for quantitation of urinary KS, a screening biomarker for Morquio A (Oguma et al., 2007; Martell et al., 2011). To ensure a reliable supply of keratanase-II, we sought to produce a Bacillus circulans-derived enzyme via a recombinant approach in Escherichia coli.. Bioinformatics analysis of the B. circulans keratanase-II enzyme identified likely dispensable C-terminal domains amenable to enhancement via protein engineering. A truncated form of the enzyme was designed to remove the domains predicted to be unnecessary for catalytic activity and detrimental to recombinant expression in E. coli.. C-terminally truncated, recombinant B. circulans keratanase-II was purified to >98% homogeneity and extensively characterised, demonstrating desired activity, specificity and utility in LC-MS-based quantitation of urinary KS from Morquio A and control samples, and is functionally indistinguishable from full-length, native B. circulans-derived keratanase-II.. This novel, recombinant keratanase-II meets all performance requirements and can be produced in a rapid and reproducible manner. We speculate that other related bacterial enzymes of biomedical or industrial interest may be amenable to similar engineered enhancements.

Topics: Acetylglucosaminidase; Adolescent; Adult; Animals; Bacillus; Bioengineering; Biomarkers; Case-Control Studies; Catalysis; Cattle; Child; Child, Preschool; Chromatography, Liquid; Cloning, Molecular; Escherichia coli; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Protein Structure, Tertiary; Tandem Mass Spectrometry; Young Adult

The objectives of this study are to quantify endurance and respiratory function and better characterize spectrum of symptoms and biochemical abnormalities in mucopolysaccharidosis IVA subjects.. MorCAP was a multicenter, multinational, cross sectional study amended to be longitudinal in 2011. Each study visit required collection of medical history, clinical assessments, and keratan sulfate (KS) levels.. Data from the first visit of 325 subjects (53% female) were available. Mean age was 14.5 years. Mean ± SD height z-scores were -5.6 ± 3.1 as determined by the CDC growth charts. Mean ± SD from the 6-minute-walk-test was 212.6 ± 152.2m, revealing limitations in functional endurance testing, and 30.0 ± 24.0 stairs/min for the 3-minute-stair-climb test. Respiratory function showed limitations comparable to MPS VI patients; mean ± SD was 1.2 ± 0.9l based on forced vital capacity and 34.8 ± 25.5l/min based on maximum voluntary ventilation. Mean urinary keratan sulfate (uKS) was elevated for all ages, and negatively correlated with age. Higher uKS correlated with greater clinical impairment based on height z-scores, endurance and respiratory function tests. The MPS Health Assessment Questionnaire reveals impairments in mobility and activities of daily living in comparison to an age-matched control population.. MPS IVA is a multisystem disorder with a continuum of clinical presentation. All affected individuals experience significant functional limitations and reduced quality of life. Older patients have more severe exercise and respiratory capacity limitations, and more frequent cardiac pathology illustrating the progressive nature of disease.

Topics: Activities of Daily Living; Adolescent; Adult; Child; Child, Preschool; Cross-Sectional Studies; Exercise; Female; Glycosaminoglycans; Humans; Infant; Infant, Newborn; Keratan Sulfate; Male; Motor Activity; Mucopolysaccharidosis IV; Physical Endurance; Quality of Life; Respiratory Function Tests; Surveys and Questionnaires; United States

G(M1) gangliosidosis and Morquio B are autosomal recessive lysosomal storage diseases associated with a neurodegenerative disorder or dwarfism and skeletal abnormalities, respectively. These diseases are caused by deficiencies in the lysosomal enzyme β-d-galactosidase (β-Gal), which lead to accumulations of the β-Gal substrates, G(M1) ganglioside, and keratan sulfate. β-Gal is an exoglycosidase that catalyzes the hydrolysis of terminal β-linked galactose residues. This study shows the crystal structures of human β-Gal in complex with its catalytic product galactose or with its inhibitor 1-deoxygalactonojirimycin. Human β-Gal is composed of a catalytic TIM barrel domain followed by β-domain 1 and β-domain 2. To gain structural insight into the molecular defects of β-Gal in the above diseases, the disease-causing mutations were mapped onto the three-dimensional structure. Finally, the possible causes of the diseases are discussed.

Topics: 1-Deoxynojirimycin; beta-Galactosidase; Crystallography, X-Ray; G(M1) Ganglioside; Galactose; Gangliosidosis, GM1; Humans; Hydrolysis; Keratan Sulfate; Lysosomes; Models, Molecular; Mucopolysaccharidosis IV; Mutation; Protein Structure, Tertiary

Morquio disease is a rare genetic disorder characterized by the accumulation of keratan sulfate in tissues. We distinguish two forms according to the deficient enzyme: type A, with a poor prognosis, and type B. Its management is essentially symptomatic. Enzyme replacement therapy and gene therapy are still being evaluated. We report observations of three patients with Morquio disease type A in its moderate form. This article reports the latest facts in both Morquio disease diagnosis and treatment, emphasizing the minor forms usually presented by short stature that should bring out this disorder.

Topics: Biomarkers; Child; Consanguinity; Dwarfism; Female; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Prognosis; Risk Factors; Severity of Illness Index

Mucopolysaccharidosis type IVA (MPS IVA, Morquio A disease), a progressive lysosomal storage disease, causes skeletal chondrodysplasia through excessive storage of keratan sulfate (KS). KS is synthesized mainly in cartilage and released to the circulation. The excess storage of KS disrupts cartilage, consequently releasing more KS into circulation, which is a critical biomarker for MPS IVA. Thus, assessment of KS level provides a potential screening strategy and determines clinical course and efficacy of therapies. We have recently developed a tandem mass spectrometry liquid chromatography [LC/MS/MS] method to assay KS levels in blood. Forty-nine blood specimens from patients with MPS IVA [severe (n = 33), attenuated (n = 11) and undefined (n = 5)] were analyzed for comparison of blood KS concentration with that of healthy subjects and for correlation with clinical severity. Plasma samples were digested by keratanase II to obtain disaccharides of KS. Digested samples were assayed by LC/MS/MS. We found that blood KS levels (0.4-26 µg/ml) in MPS IVA patients were significantly higher than those in age-matched controls (0.67-4.6 µg/ml; P < 0.0001). It was found that blood KS level varied with age and clinical severity in the patients. Blood KS levels in MPS IVA peaked between 2 years and 5 years of age (mean 11.4 µg/ml). Blood KS levels in severe MPS IVA (mean 7.3 µg/ml) were higher than in the attenuated form (mean 2.1 µg/ml) (P = 0.012). We also found elevated blood KS levels in other types of MPS. These findings indicate that the new KS assay for blood is suitable for early diagnosis and longitudinal assessment of disease severity in MPS IVA.

Topics: Adolescent; Adult; Biomarkers; Case-Control Studies; Child; Child, Preschool; Chromatography, Liquid; Early Diagnosis; Humans; Infant; Keratan Sulfate; Middle Aged; Mucopolysaccharidosis IV; Predictive Value of Tests; Reproducibility of Results; Severity of Illness Index; Tandem Mass Spectrometry; Up-Regulation; Young Adult

Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is a lysosomal storage disorder caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), an enzyme that degrades keratan sulfate (KS). Currently no therapy for MPS IVA is available. We produced recombinant human (rh)GALNS as a potential enzyme replacement therapy for MPS IVA. Chinese hamster ovary cells stably overexpressing GALNS and sulfatase modifying factor-1 were used to produce active ( approximately 2 U/mg) and pure (>or=97%) rhGALNS. The recombinant enzyme was phosphorylated and was dose-dependently taken up by mannose-6-phosphate receptor (K(uptake) = 2.5 nM), thereby restoring enzyme activity in MPS IVA fibroblasts. In the absence of an animal model with a skeletal phenotype, we established chondrocytes isolated from two MPS IVA patients as a disease model in vitro. MPS IVA chondrocyte GALNS activity was not detectable and the cells exhibited KS storage up to 11-fold higher than unaffected chondrocytes. MPS IVA chondrocytes internalized rhGALNS into lysosomes, resulting in normalization of enzyme activity and decrease in KS storage. rhGALNS treatment also modulated gene expression, increasing expression of chondrogenic genes Collagen II, Collagen X, Aggrecan and Sox9 and decreasing abnormal expression of Collagen I. Intravenous administration of rhGALNS resulted in biodistribution throughout all layers of the heart valve and the entire thickness of the growth plate in wild-type mice. We show that enzyme replacement therapy with recombinant human GALNS results in clearance of keratan sulfate accumulation, and that such treatment ameliorates aberrant gene expression in human chondrocytes in vitro. Penetration of the therapeutic enzyme throughout poorly vascularized, but clinically relevant tissues, including growth plate cartilage and heart valve, as well as macrophages and hepatocytes in wild-type mouse, further supports development of rhGALNS as enzyme replacement therapy for MPS IVA.

Topics: Animals; Biological Transport; Cartilage; Cattle; Chondrocytes; Chondroitinsulfatases; Enzyme Replacement Therapy; Female; Gene Expression Regulation; Growth Plate; Heart Valves; Humans; Keratan Sulfate; Liver; Lysosomes; Macrophages; Mice; Mucopolysaccharidosis IV; Recombinant Proteins

Topics: Abnormalities, Multiple; Adult; Amniocentesis; Amnion; Amniotic Fluid; Chondroitinsulfatases; Diagnosis, Differential; Equinus Deformity; Female; Fetus; Glycosaminoglycans; Humans; Hydrops Fetalis; Infant, Newborn; Keratan Sulfate; Mucopolysaccharidosis IV; Pregnancy; Pregnancy Trimester, Second

Mucopolysaccharidosis IVA (MPS IVA; Morquio A disease) is an autosomal-recessive disorder caused by a deficiency of lysosomal N-acetylgalactosamine-6-sulfate sulfatase (GALNS; E.C.3.1.6.4). GALNS is required to degrade glycosaminoglycans, keratan sulfate (KS), and chondroitin-6-sulfate. Accumulation of undegraded substrates in lysosomes of the affected tissues leads to a systemic bone dysplasia. We summarize information on 148 unique mutations determined to date in the GALNS gene, including 26 novel mutations (19 missense, four small deletions, one splice-site, and two insertions). This heterogeneity in GALNS gene mutations accounts for an extensive clinical variability within MPS IVA. Seven polymorphisms that cause an amino acid change, and nine silent variants in the coding region are also described. Of the analyzed mutant alleles, missense mutations accounted for 78.4%; small deletions, 9.2%; nonsense mutation, 5.0%; large deletion, 2.4%; and insertions, 1.6%. Transitional mutations at CpG dinucleotides accounted for 26.4% of all the described mutations. The importance of the relationship between methylation status and distribution of transitional mutations at CpG sites at the GALNS gene locus was elucidated. The three most frequent mutations (over 5% of all mutations) were represented by missense mutations (p.R386C, p.G301C, and p.I113F). A genotype/phenotype correlation was defined in some mutations. Missense mutations associated with a certain phenotype were studied for their effects on enzyme activity and stability, the levels of blood and urine KS, the location of mutations with regard to the tertiary structure, and the loci of the altered amino acid residues among sulfatase proteins.

Topics: Animals; Chondroitinsulfatases; CpG Islands; DNA Methylation; Genotype; Humans; Keratan Sulfate; Mice; Mucopolysaccharidosis IV; Mutation; Polymorphism, Genetic; Protein Structure, Tertiary

Mucopolysaccharidosis IVA (MPS IVA), a progressive lysosomal storage disease, causes skeletal dysplasia through excessive storage of keratan sulfate (KS). We developed an ELISA-sandwich assay that used a MAb specific to KS. Forty-five blood and 59 urine specimens from MPS IVA patients (ages 1-65 y) were analyzed to determine whether KS concentration is a suitable marker for early diagnosis and longitudinal assessment of disease severity. Blood specimens were obtained from patients categorized as phenotypically severe (n = 36) and milder (n = 9). Urine specimens were also analyzed from patients categorized as severe (n = 56) and milder (n = 12), respectively. Blood KS levels (101-1525 ng/mL) in MPS IVA patients were two to eight times higher than those in age-matched controls (15-323 ng/mL). It was found that blood KS level varied with age and clinical severity. Blood KS levels in both MPS IVA and controls peaked between 5 and 10 y of age (mean, 776 versus 234 ng/mL, respectively). Blood levels in severe MPS IVA were 1.5 times higher than in the milder form. In contrast to blood, urine KS levels in both MPS IVA and controls peaked between 1 and 5 y (15.3 versus 0.26 mg/g creatinine), and thereafter declined with age. Urine KS level also varied with age and clinical severity, and the severe MPS IVA phenotype was associated with 6.7 times greater urine KS excretion than the milder one. These findings indicate that the new assay for blood or urine KS may be suitable for early diagnosis and longitudinal assessment of disease severity in MPS IVA.

Topics: Adolescent; Adult; Aged; Biomarkers; Child; Child, Preschool; Diagnosis, Differential; Enzyme-Linked Immunosorbent Assay; Genetic Testing; Glycosaminoglycans; Humans; Infant; Keratan Sulfate; Middle Aged; Mucopolysaccharidosis IV; Reproducibility of Results; Statistics as Topic

G(M1)-gangliosidosis and Morquio B disease are distinct in clinical and biochemical features, but both disorders are caused by genetic defects of the same enzyme, acid beta-galactosidase (beta-Gal). We analyzed the kinetic properties of mutant beta-Gals from patients with G(M1)-gangliosidosis and Morquio B disease to examine the clinical and biochemical differences between both disorders. Five skin fibroblast lines from patients with G(M1)-gangliosidosis (2 cases; R201C/R201C and I51T/I51T), Morquio B disease (2 cases; W273L/W273L and Y83H/R482C), and galactosialidosis (1 case; Y395C/S90L) were used as enzyme sources. Residual enzyme activity in the cells was subjected to kinetic analysis. Substrate analogs including Galbeta1-3GalNAc, as an analog for G(M1)-ganglioside, and Galbeta1-4GlcNAc, as an analog for keratan sulfate, were used to determine IC(50) and K(i) for beta-Gals with an artificial substrate (4-methylumbelliferyl beta-D-galactopyranoside). Enzymatic assay method was established to examine the hydrolytic activity with the mutant beta-Gal for the substrate analogs. The mutant beta-Gal activities were inhibited by Galbeta1-3GalNAc and Galbeta1-4GlcNAc in a concentration-dependent manner. Remarkable increase in IC(50) ratio and K(i) ratio (Galbeta1-4GlcNAc/Galbeta1-3GalNAc) was observed in Morquio B disease. Relative hydrolytic activity (Galbeta1-4GlcNAc/Galbeta1-3GalNAc) was markedly decreased in Morquio B disease as compared with other subjects; controls (means+/-SD, n=4), 1.00+/-0.02; galactosialidosis, 1.03; G(M1)-gangliosidosis, 1.15 and 1.00; and Morquio B disease, 0.27 and 0.32. The mutant beta-Gals from the patients with Morquio B disease exhibited lower affinity and lower hydrolytic activity toward Galbeta1-4GlcNAc rather than Galbeta1-3GalNAc. These findings suggest that imbalanced substrate specificity of the mutant beta-Gals induces predominant accumulation of keratan sulfate and a rationale for performing differential diagnostic analysis for both disorders.

Topics: Antigens, Tumor-Associated, Carbohydrate; beta-Galactosidase; Cell Line; Fibroblasts; Glycosaminoglycans; Humans; Hydrolysis; Keratan Sulfate; Kinetics; Mucopolysaccharidosis IV; Mutation; Substrate Specificity

We describe a Czech patient with combined adenine phosphoribosyltransferase (APRT) deficiency (2,8-dihydroxyadenine urolithiasis) and N-acetylgalactosamine-6-sulfate sulfatase (GALNS) deficiency (mucopolysaccharidosis Type IVA, Morquio disease A). Adenine and its extremely insoluble derivative, 2,8-dihydroxyadenine, were identified in the urine, and APRT deficiency was confirmed in erythrocytes. There was excessive excretion of keratan sulfate in the urine, and GALNS deficiency was confirmed in leukocytes. GALNS and APRT are both located on chromosome 16q24.3, suggesting that the patient had a deletion involving both genes. PCR amplification of genomic DNA indicated that a novel junction was created by the fusion of sequences distal to GALNS exon 2 and proximal to APRT exon 3, and that the size of the deleted region was approximately 100 kb. The deletion breakpoints were localized within GALNS intron 2 and APRT intron 2. Several other genes, including the alpha subunit of cytochrome B (CYBA), which is deleted or mutated in the autosomal form of chronic granulomatous disease, are located in the 16q24.3 region, but PCR amplification showed that this gene was present in the proband. A patient with hemizygosity for GALNS deficiency and APRT deficiency has been reported from Japan recently. These findings indicate that: (i) APRT is located telomeric to GALNS; (ii) GALNS and APRT are transcribed in the same orientation (centromeric to telomeric); and (iii) combined APRT/GALNS deficiency may be more common than hitherto realized.

Topics: Adenine Phosphoribosyltransferase; Base Sequence; Child; Chondroitinsulfatases; Chromosome Deletion; Chromosomes, Human, Pair 16; DNA; DNA Mutational Analysis; Family Health; Female; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Pedigree; Sequence Deletion

Mucopolysaccharidosis type IVA (Morquio A) is caused by a deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), an enzyme capable of cleaving the sulfate group from both N-acetylgalactosamine-6-sulfate and galactose-6-sulfate. We describe here a two-generation Morquio A family with two distinct clinical phenotypes. The two probands from the second generation showed intermediate signs of the disease whereas their affected mother, aunt and two uncles had only very mild symptoms. Galactose-6-sulfatase (GALS) activity in leukocytes and fibroblasts of the affected family members was clearly deficient. Molecular genetic analysis of the GALNS gene revealed that two different point mutations segregate in the family, which correlated well with the clinical phenotype. The probands with intermediate symptoms were compound heterozygotes for the mutations R259Q and R94G, the latter one being inherited from the unaffected father. The mother and her affected siblings with the unusually mild phenotype were proven to be homozygous for the novel missense point mutation R259Q.

Topics: Adolescent; Adult; Aged; Amino Acid Substitution; Chondroitinsulfatases; DNA Mutational Analysis; Family; Family Health; Female; Galactose; Genes; Glycosaminoglycans; Humans; Keratan Sulfate; Leukocytes; Male; Mucopolysaccharidosis IV; Pedigree; Point Mutation; Sulfatases

Keratan sulfate (KS) was immunolocalized in the chinchilla cochlea and vestibular system using indirect immunohistochemistry and a monoclonal antibody (clone 5-D-4) directed against a proteoglycan core antigen. As a positive control, anti-KS Mab reactivity was found in the pericellular matrix and lacuna walls of temporal bone osteocytes. In the cochlea, anti-KS Mab reactivity was abundant in the basal cell layer of the stria vascularis and in the marginal band and Hensen's stripe of the tectorial membrane. Less anti-KS Mab reactivity was present in the cover net, Hardesty's membrane and the upper fibrous zone of the limbal layer of the tectorial membrane. In the vestibular system, anti-KS Mab reactivity was immunolocalized to a portion of the epithelium overlying the cupula of the crista ampullaris, in the apical surface of crista ampullaris epithelium, crista ampullaris stereocilia and in the otoconia. Elucidating the distribution of KS in the cochlea will improve our understanding of cochlear anatomy and is a first step toward understanding the etiology of hearing loss observed in diseases involving KS metabolism, namely, mucopolysaccharidosis type IV (Morquio's syndrome).

Topics: Animals; Antibodies, Monoclonal; Cats; Chinchilla; Cochlea; Female; Fluorescein-5-isothiocyanate; Frozen Sections; Gerbillinae; Horseradish Peroxidase; Immunohistochemistry; Keratan Sulfate; Mucopolysaccharidosis IV; Osteocytes; Rabbits; Species Specificity; Stria Vascularis; Tectorial Membrane; Temporal Bone

Morquio syndrome (mucopolysaccharidosis IV) presents with multiple bone dysplasia and is characterized by the inability to degrade keratan sulfate due to deficient N-acetylgalactosamine-6-sulfate sulfatase in Morquio A syndrome and deficient beta-D-galactosidase in Morquio B syndrome. The aim of our study was to investigate into the pathogenetic mechanism as it is not clear whether the accumulation of keratan sulfate is toxic for osteoblasts or inhibits osteoblast activity as e.g. bone resorption. The glycosaminoglycans keratan sulfate, heparan sulfate, dermatan sulfate, chondroitin-4,6-sulfate and hyaluronic acid were tested in rat neonatal calvarian cultures for their effects on bone resorption, osteoblast activity and toxicity. Bone resorption was evaluated by calcium release into the medium, osteoblast activity by the determination of alkaline phosphatase and toxicity by measuring lactate dehydrogenase in the culture media. Keratan sulfate had no effect on bone resorption but inhibited osteoblast activity at the low, nontoxic concentration of 10 ng per ml organ culture supernatant significantly (p<0.05). At a concentration of 100 ng per ml keratan sulfate revealed toxic effects as reflected by significantly (p<0.05) elevated lactate dehydrogenase activity. None of the other glycosaminoglycans inhibited osteoblast activities. Heparan sulfate showed at toxic levels (10 microg per ml supernatant) significantly increased bone resorption (p<0.05) accompanied by increased alkaline phosphatase activity. The specific keratan sulfate effects of inhibiting osteoblast activity and toxicity towards bone, which were never tested before, suggest a role for this glycosaminoglycan in the pathogenesis of bone dysplasia in Morquio syndrome.

Topics: Animals; Animals, Newborn; Bone and Bones; Bone Resorption; Calcium; Heparitin Sulfate; Keratan Sulfate; L-Lactate Dehydrogenase; Mucopolysaccharidosis IV; Organ Culture Techniques; Rats; Rats, Wistar

A fetus with mucopolysaccharidosis type IV A (Morquio type A) is described. The family had one affected child exhibiting symptoms of classical Morquio A disease, and late in the subsequent pregnancy prenatal diagnosis was requested. At 23 weeks' gestation, moderate ascites was detected by detailed ultrasound scan and keratan sulphate was found in the amniotic fluid. The pregnancy was terminated by prostaglandin induction and the diagnosis of mucopolysaccharidosis type IV A was confirmed by demonstration of a deficiency of N-acetylgalactosamine-6-sulphate (GalNac-6-S) sulphatase in cultured amniotic cells and in post-mortem fibroblast cultures. The activities of beta-galactosidase and arylsulphatase A were normal, ruling out Morquio disease type B and multiple sulphatase deficiency. These results indicate that mucopolysaccharidosis IV A (a disease that predominantly affects the skeletal system) may produce ascites in the fetus to such an extent that it can be detected by ultrasound.

Topics: Amniocentesis; Amniotic Fluid; Ascites; beta-Galactosidase; Child; Consanguinity; Electrophoresis; Female; Glycosaminoglycans; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Neuraminidase; Placenta; Pregnancy; Pregnancy Trimester, Second; Sulfatases; Ultrasonography

Chemical structures of keratan sulfate (KS) isolated from the liver affected by Morquio syndrome type A (classical type) were investigated. In the KS from Morquio syndrome liver, the molar ratios of hexose, total sulfate, N-sulfate and sialic acid to hexosamine were 5.07, 0.90, 0.18 and 0.08, respectively, and about 10% of hexosamine consisted of galactosamine. The KS resulted in a production of oligosaccharides of relatively larger size after digestion with keratanase, as compared with bovine corneal KS. These findings strongly suggest that KS accumulated in the liver affected by Morquio syndrome may be derived from bony KS.

Topics: Animals; Bone and Bones; Cattle; Chemical Phenomena; Chemistry; Cornea; Glycosaminoglycans; Humans; Keratan Sulfate; Liver; Molecular Weight; Mucopolysaccharidosis IV

Two children of second-cousin parents were found to have a very mild form of Morquio syndrome. The 14-year-old boy was 147 cm tall and had fine corneal deposits, a broad chest, dislocated hips, and flat feet. His 7-year-old sister had a broad chest but otherwise normal physical development. An abnormal lumbar spine was seen in radiographs of both children. Analysis of the urine from the affected children showed levels of acid mucopolysaccharides (AMPS) up to twice as high as that found in normal urine, but no evidence of keratosulfaturia. Most urinary AMPS was chondroitin-6-sulfate. Multiple assays of N-acetylgalactosamine-6-sulfate (GalNAc-6-SO4) sulfatase in leukocytes and cultured skin fibroblasts showed deficiency of this enzyme in the range found in the classical form of Morquio (Morquio A) syndrome. This report identifies an enzymatic defect in one form of non-keratan-sulfate-excreting Morquio (NKSE Morquio) syndrome and confirms the absence of keratosulfaturia in this mild form of Morquio disease.

Topics: Adolescent; Child; Chondroitin; Chondroitin Sulfates; Consanguinity; Female; Fibroblasts; Genes, Recessive; Genetic Variation; Glycosaminoglycans; Humans; Keratan Sulfate; Leukocytes; Male; Mucopolysaccharidosis IV; Pedigree

Topics: Cells, Cultured; Chondroitin Sulfates; Chondroitinsulfatases; Fibroblasts; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Skin; Substrate Specificity

Upon incubation of keratan [35S]sulphate with normal fibroblasts both [35S]sulphate and N-acetylglucosamine 6-[35S]sulphate are liberated. From the products obtained after digestion with various mutant fibroblasts and with purified N-acetylgalactosamine 6-sulphate sulphatase we suggest that (i) [35S]sulphate is released almost exclusively from galactose 6-sulphate residues; (ii) N-acetylgalactosamine 6-sulphate sulphatase exhibits galactose 6-sulphate sulphatase activity; (iii) both sulphatase activities are deficient in Morquio disease type A.

Topics: Cell Line; Chondroitinsulfatases; Fibroblasts; Glycosaminoglycans; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Sulfatases

We have prepared a new substrate (o-beta-D-sulfo-galactosyl-(1-4)-beta-D-6-sulfo-2-acetamido-2-deoxyglucosyl- (1-4)-D-[1-3H]galactitol), from shark cartilage keratan sulfate, for the assay of galactose 6-sulfate sulfatase activity. Using this substrate, we found there was a striking deficiency of galactose 6-sulfate sulfatase activity, in addition to the known deficiency of N-acetylgalactosamine 6-sulfate sulfatase, in the cultured skin fibroblasts of patients with Morquio syndrome. Our results could be explained by the hypothesis that accumulation of keratan sulfate and chondroitin 6-sulfate in Morquio syndrome is due to a deficiency of galactose 6-sulfate sulfatase and N-acetylgalactosamine 6-sulfate sulfatase activity, which are necessary for the degradation of these two mucopolysaccharides.

Topics: Animals; Cartilage; Cells, Cultured; Chondroitinsulfatases; Female; Fibroblasts; Humans; Keratan Sulfate; Methods; Mucopolysaccharidosis IV; Oligosaccharides; Placenta; Pregnancy; Sharks

Acidic glycosaminoglycans (GAGs) and gangliosides were analyzed in the brains from control fetuses, fetal Hurler syndrome, control children and three patients affected by genetic mucopolysaccharidosis (Hurler, Hunter and Morquio syndromes). GAGs contents in the brains from patients with Hurler and Hunter syndromes were approximately 1.5-3.0-fold greater as compared with those controls, and most of the GAGs were much more degraded than those from controls. Dermatan sulfate (DS), which was not identified in the control brains, comprised about 20--40% of the total GAGs. On the other hand, GAGs content and molecular weight distribution in the brain from the patient affected by Morquio syndrome were similar to those in the control brains. GAGs content in the brain from fetal Hurler syndrome was also 2.0-fold greater and DS, which was not detected in the control fetal brains, comprised 1.6% of the total GAGs. However, the molecular weight distribution of the GAGs was similar to those of the control fetal brains. The total amount of the brain gangliosides in all patients assayed here was similar to those in the control brains. However, a greater amount of GM1- and Gm2-gangliosides was observed in the brains from patients with Hurler and Hunter syndromes.

Topics: Adolescent; Brain; Brain Chemistry; Child; Child, Preschool; Dermatan Sulfate; Fetus; Gangliosides; Glycosaminoglycans; Humans; Infant; Keratan Sulfate; Mucopolysaccharidosis I; Mucopolysaccharidosis II; Mucopolysaccharidosis IV

Topics: Child; Diagnosis, Differential; Glycosaminoglycans; Growth Hormone; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Thyrotropin

To elucidate precise chemical nature of urinary keratan sulfate (KS) of Morquio's disease, crude glycosaminoglycans (GAG) were separated from 24-hr urines of 3 patients with Morquio's disease and from pooled urine of a healthy boy, using cetylpyridinium chloride. KS fractions were then separated from the crude GAG after removal of other GAG and acidic glycopeptide by successive digestion with testicular hyaluronidase and chondroitinase ABC, and by nitrous acid treatment, followed by Dowex 1 column chromatography. The distribution of KS in several fractions (1.5 M Fr-5.0 M Fr) obtained by Dowex 1 column chromatography suggested polydispersity of urinary KS. The relative amounts (micrograms/24-hr urine/kg body weight) of the KS fractions excreted into Morquio's urine were 52-63 times as much as that excreted into normal urine. The KS fractions contained galactose, glucosamine and sulfate as the major constituents, together with fairly amounts of galactosamine and sialic acid, and small amounts of mannose, L-fucose and glucose. The KS fractions resembled sulfated glycopeptide with respect to the sugar composition. The contents of sulfate and sialic acid in each KS fraction from Morquio's urine were higher than those in the corresponding one from normal urine, whereas opposite was the case for the ratio of glucosamine to galactosamine. The sulfate contents in the KS fractions from Morquio's urine indicated that the patient excreted over-sulfated KS into urine. The chemical compositions of the KS fractions from Morquio's urine suggest that the sulfatase specific for 6-sulfate linked to sugars with the galactose configuration may act in a early step of the catabolism of oversulfated KS in the normal tissues.

Topics: Adolescent; Child; Female; Glycosaminoglycans; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV

Glycosaminoglycan content, composition and molecular weight were determined in liver obtained from a patient with Morquio syndrome (Mucopolysaccharidosis IV). There was about a four-fold increase in glycosaminoglycan content (as hexosamine) of the affected liver as compared to the control liver. The major glycosaminoglycan accumulated in the liver was keratan sulfate, which was not found in the control liver. Chondroitin sulfates, especially chondroitin 6-sulfate, were also increased. Heparan sulfate isolated from the liver of a patient with Morquio syndrome was structurally different to that from control liver, and the glycosaminoglycans from Morquio syndrome were of a much lower molecular weight than those from control.

Topics: Adolescent; Child; Chondroitin Sulfates; Chromatography, Gel; Electrophoresis, Cellulose Acetate; Female; Glycosaminoglycans; Humans; Keratan Sulfate; Liver; Male; Molecular Weight; Mucopolysaccharidosis IV; Syndrome

Simple methods for the detection of keratan sulphate in urine have been applied to over 300 urine samples collected from children and adults with bone and cartilage dysplasias with or without mental retardation. Abnormal keratan sulphate excretion, which is a feature of type IV mucopolysaccharidosis (Morquio syndrome), is found in patients with that condition only during childhood. Abnormal excretion is also a feature of Kniest dysplasia and GM1 gangliosidosis and may be present in a number of other bone and cartilage dysplasias of unknown aetiology.

Topics: Adolescent; Adult; Bone Diseases; Child; Child, Preschool; Female; Glycosaminoglycans; Humans; Infant; Keratan Sulfate; Male; Middle Aged; Mucopolysaccharidosis IV; Tay-Sachs Disease

[1-3H]Galactitol-6-sulfate, N- [1-3H]acetylgalactosaminitol-6-sulfate, N-[1-3H]acetylglucosaminitol-6-sulfate, N-acetylglucosamine-6-sulfate, and 6-sulfated tetrasaccharides from chondroitin-6-sulfate have been used for the measurement of 6-sulfatase activity of extracts of normal skin fibroblasts and of fibroblasts cultured from patients with genetic mucopolysaccharidoses. With these substrates, extracts of fibroblasts derived from Morquio patients lack or have greatly reduced activities for galactitol-6-sulfate, N-acetylgalactosaminitol-6-sulfate, and 6-sulfated tetrasaccharides but have normal activity for N-acetylglucosamine-6-sulfate and its alditol; those derived from a patient with a newly discovered mucopolysaccharidosis have greatly reduced activity for N-acetylglucosamine-6-sulfate and its alditol but normal activity for galactitol-6-sulfate, N-acetylgalactosaminitol-6-sulfate, and the 6-sulfated tetrasaccharides. These findings demonstrate the existence of two different hexosamine-6-sulfate sulfatases, specific for the glucose or galactose configuration of their substrates. Their respective deficiencies, causing inability to degrade keratan sulfate and heparan sulfate in one case and keratan sulfate and chondroitin-6-sulfate in the other, are responsible for different clinical phenotypes.

Topics: Acetylgalactosamine; Acetylglucosamine; Cells, Cultured; Child, Preschool; Chondroitin Sulfates; Chondroitinsulfatases; Fibroblasts; Galactitol; Heparitin Sulfate; Humans; Hydrogen-Ion Concentration; Keratan Sulfate; Male; Mucopolysaccharidoses; Mucopolysaccharidosis III; Mucopolysaccharidosis IV; Skin; Substrate Specificity; Sulfatases

Topics: Cartilage Diseases; Collagen; Genes, Dominant; Glycosaminoglycans; Heparitin Sulfate; Hip Dislocation, Congenital; Humans; Keratan Sulfate; Mucopolysaccharidosis IV; Osteogenesis Imperfecta; Scoliosis

Topics: Abnormalities, Multiple; Bone and Bones; Child, Preschool; Chondrocytes; Chondroitin Sulfates; Consanguinity; Diagnosis, Differential; Glycosaminoglycans; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Osteochondrodysplasias; Radiography; Research; Sulfatases

Topics: Child; Child, Preschool; Humans; Keratan Sulfate; Male; Mucopolysaccharidosis IV; Radiography