myelin-basic-protein and Intellectual-Disability

We studied 14 individuals with partial deletions of the long arm of chromosome 18, including terminal and interstitial de novo and inherited deletions. Study participants were examined clinically and by brain MRI. The size of the deletion was determined by segregation analysis using microsatellite markers. We observed that the phenotype was highly variable, even in two families with three 1st degree relatives. Among the 14 individuals, general intelligence varied from normal to severe mental retardation. The more common features of 18q-deletions (e.g., foot deformities, aural atresia, palatal abnormalities, dysmyelination, and nystagmus) were present in individuals lacking only the distal portion 18q22.3-qtel. Interstitial deletions exerted very heterogeneous effects on phenotype. In individuals with distal 18q22.3-q23 deletions, brain MRI was very distinctive with poor differentiation of gray and white matter on T2-weighted images.

Topics: Abnormalities, Multiple; Adolescent; Adult; Brain; Child; Child, Preschool; Chromosome Deletion; Chromosome Segregation; Chromosomes, Human, Pair 18; Female; Humans; Infant; Intellectual Disability; Magnetic Resonance Imaging; Male; Microsatellite Repeats; Myelin Basic Protein; Phenotype

We report on a 12-year-old boy who presented with delayed development and CNS dysmyelination. Genetic studies showed a normal 46,XY karyotype by routine cytogenetic analysis, and 46,XY.ish del(18)(q23)(D18Z1+, MBP-) by FISH using a locus-specific probe for the MBP gene (18q23). Though the patient appeared to have normal chromosome 18s by repeated high resolution banding analysis, his clinical features were suggestive of a deletion of 18q. These included hearing loss secondary to stenosis of the external auditory canals, abnormal facial features, and foot deformities. FISH studies with genomic probes from 18q22.3 to 18qter confirmed a cryptic deletion which encompassed the MBP gene. In an attempt to further characterize the deletion, whole genome screening was conducted using array based comparative genomic hybridization (array CGH) analysis. The array CGH data not only confirmed a cryptic deletion in the 18q22.3 to 18qter region of approximately 7 Mb, it also showed a previously undetected 3.7 Mb gain of 4q material. FISH studies demonstrated that the gained 4q material was translocated distal to the 18qter deletion breakpoint. The 18q deletion contains, in addition to MBP, other known genes including CYB5, ZNF236, GALR1, and NFATC1, while the gained 4q material includes the genes FACL1 and 2, KLKB1, F11 and MTNR1A. The use of these combined methodologies has resulted in the first reported case in which array CGH has been used to characterize a congenital chromosomal abnormality, highlighting the need for innovative molecular cytogenetic techniques in the diagnosis of patients with idiopathic neurological abnormalities.

Topics: Central Nervous System; Child; Chromosome Banding; Chromosomes, Human, Pair 18; Chromosomes, Human, Pair 4; Cytogenetics; DNA; Gene Deletion; Genotype; Hearing Loss; Humans; In Situ Hybridization, Fluorescence; Intellectual Disability; Karyotyping; Magnetic Resonance Imaging; Male; Models, Genetic; Myelin Basic Protein; Myelin Sheath; Nucleic Acid Hybridization; Translocation, Genetic

Based on a possible pathological relationship of autoimmunity to autism, antibodies reactive with myelin basic protein (anti-MBP) were investigated in the sera of autistic children. Using a screening serum dilution of 1:400 in the protein-immunoblotting technique, approximately 58% (19 of 33) sera of autistic children (< or = 10 years of age) were found to be positive for anti-MBP. This result in autistics was significantly (p < or = .0001) different from the controls (8 of 88 or only 9% positive), which included age-matched children with normal health, idiopathic mental retardation (MR) and Down syndrome (DS), and normal adults of 20 to 40 years of age. Since autism is a syndrome of unknown etiology, it is possible that anti-MBP antibodies are associated with the development of autistic behavior.

Topics: Adult; Age Factors; Antibody Specificity; Autistic Disorder; Autoantibodies; Autoimmune Diseases; Child; Child, Preschool; Double-Blind Method; Down Syndrome; Female; Humans; Infant; Intellectual Disability; Male; Myelin Basic Protein; Nerve Tissue Proteins

Cell-mediated immune response to human myelin basic protein was studied by the macrophage migration inhibition factor test in 17 autistic patients and a control group of 11 patients suffering from other mental diseases included in the differential diagnosis of the syndrome of autism. Of the 17 autistic patients, 13 demonstrated inhibition of macrophage migration, whereas none of the nonautistic patients showed such a response. The results indicate the existence of a cell-mediated immune response to brain tissue in the syndrome of autism.

Topics: Adolescent; Adult; Autistic Disorder; Brain; Cell Migration Inhibition; Child; Female; Humans; Intellectual Disability; Macrophage Migration-Inhibitory Factors; Macrophages; Male; Myelin Basic Protein; Schizophrenia, Childhood