hydroxocobalamin and Proteinuria

Prospective studies on maintenance treatment for Beagles with hereditary selective cobalamin (Cbl) malabsorption (Imerslund-Gräsbeck syndrome, IGS) are lacking. In our experience, measurement of methylmalonic acid (MMA), a Cbl-dependent metabolite, seems more helpful to monitor Cbl status as compared with serum Cbl concentrations.. To evaluate a standardized Cbl supplementation scheme in Beagles with IGS. We hypothesized that a single parenteral dose of 1 mg hydroxocobalamin (OH-Cbl) would maintain clinical and metabolic remission for up to 2 months.. Six client-owned juvenile Beagles with genetically confirmed IGS and 28 healthy control dogs.. Prospective study. Monthly IM OH-Cbl (1 mg) supplementation was done over a median of 9 months (range, 6-13) in 6 dogs, followed by bimonthly (every 2 months) injections in 5 dogs over a median of 6 months (range, 3-10). Health status was assessed by routine clinical examinations at injection time points and owner observations. Voided urine samples were collected immediately before OH-Cbl injections for measurement of MMA-to-creatinine concentrations using a gas-liquid chromatography-tandem mass spectrometry (GC-MS) method.. All dogs were clinically healthy while receiving monthly and bimonthly OH-Cbl supplementation. Urinary MMA results in healthy dogs ranged from 1.3 to 76.5 mmol/mol creatinine (median, 2.9). Median urinary MMA concentrations did not differ between dogs with IGS receiving monthly (n = 49; 5.3 mmol/mol creatinine; range, 2.3-50.4) and bimonthly (n = 31; 5.3 mmol/mol creatinine; range, 1.6-50) injections.. A maintenance parenteral dose of 1 mg OH-Cbl monthly or bimonthly appears adequate in Beagles with IGS monitored by metabolic testing.

Topics: Anemia, Megaloblastic; Animals; Creatinine; Dog Diseases; Dogs; Drug Administration Schedule; Female; Hydroxocobalamin; Injections, Intramuscular; Malabsorption Syndromes; Male; Methylmalonic Acid; Prospective Studies; Proteinuria; Vitamin B 12; Vitamin B 12 Deficiency

Topics: Adolescent; Biopsy; Complement System Proteins; Female; Hematuria; Humans; Hydroxocobalamin; Hypertension; Intellectual Disability; Kidney; Laser-Doppler Flowmetry; Metabolism, Inborn Errors; Proteinuria; Seizures; Ultrasonography

cblC disease is a cause of hemolytic uremic syndrome (HUS), which has been primarily described in neonates and infants with severe renal and neurological lesions.. Two sisters aged 6 and 8.5 years presented with a latent hemolytic process characterized by undetectable or low plasma haptoglobin, respectively, associated with renal failure and gross proteinuria. Renal biopsies performed in both patients found typical findings of thrombotic microangiopathy suggesting the diagnosis of HUS. Both patients were free of neurologic signs.. Biochemical investigations found a cobalamin processing deficiency of the cblC type. Search for additional factors susceptible to worsen endothelial damage revealed homozygosity 677C--> T mutation in the methylenetetrahydrofolate reductase gene as well as heterozygosity for a 3254T--> C mutation in factor H in the patient with the most severe clinical presentation. Long-term subcutaneous administration of hydroxocobalamin in combination with oral betaine and folic acid resulted in clinical and biological improvement in both patients.. cblC disease may be a cause of chronic HUS with delayed onset in childhood. Superimposed mutation of factor H gene might influence clinical severity.

Topics: Anemia; Betaine; Child; Combined Modality Therapy; Complement Factor H; Drug Therapy, Combination; Endothelium, Vascular; Female; Folic Acid; Genetic Predisposition to Disease; Genotype; Haptoglobins; Hemolytic-Uremic Syndrome; Humans; Hydroxocobalamin; Hypertension; Kidney; Methylenetetrahydrofolate Reductase (NADPH2); Mutation, Missense; Nephrotic Syndrome; Plasma Exchange; Point Mutation; Proteinuria; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-cbl; Renal Dialysis; Vitamin B 12

Two siblings, a boy age 12 and his sister age 4 years, presented with proteinuria and hematuria, hypertension, and chronic hemolytic anemia. At age 13 years, the boy developed an episode of severe hypertensive encephalopathy and transient renal failure. Both children are attending normal school, have no neurologic symptoms, and only minimal pigmentary retinal abnormalities. Renal biopsy showed a chronic thrombotic microangiopathic nephropathy. Both patients had hyperhomocysteinemia and mild methylmalonic aciduria. Fibroblasts showed decreased cobalamin uptake, reduced methyl- and adenosyl-cobalamin formation, and deficient incorporation of formate and propionate, compatible with the Cbl-C complementation group, but milder than that found in cells from most patients. Both patients and their father carry a balanced reciprocal translocation. Parenteral hydroxycobalamin treatment reduced the homocysteine levels, and methylmalonic acid disappeared. Increasing the dosage of hydroxycobalamin from 1 to 2.5, then 5 mg daily together with betaine, further reduced homocysteine levels (boy from 118 to 23 microM and girl from 59 to 14 microM). With this treatment, hemolysis has stopped, hematuria has disappeared, proteinuria has almost normalized, and creatinine clearance has been stable. Investigations for chronic thrombotic microangiopathy should include testing for this unusual but treatable disorder, regardless of age of presentation.

Topics: Age of Onset; Child; Child, Preschool; Female; Hematinics; Hematuria; Hemolysis; Hemolytic-Uremic Syndrome; Homocysteine; Humans; Hydroxocobalamin; Kidney; Male; Methylmalonic Acid; Microcirculation; Proteinuria; Thrombosis; Vitamin B 12 Deficiency