title: Magnetic resonance imaging demonstrates incomplete myelination in 18q- syndrome: evidence for myelin basic protein haploinsufficiency.
abstract: Magnetic resonance imaging (MRI) and MRI relaxometry were used to investigate disturbed brain myelination in 18q- syndrome, a disorder characterized by mental retardation, dysmorphic features, and growth failure. T1-weighted and dual spin-echo T2-weighted MR images were obtained, and T1 and T2 parametric image maps were created for 20 patients and 12 controls. MRI demonstrated abnormal brain white matter in all patients. White matter T1 and T2 relaxation times were significantly prolonged in patients compared to controls at all ages studied, suggesting incomplete myelination. Chromosome analysis using fluorescence in situ hybridization techniques showed that all patients with abnormal MRI scans and prolonged white matter T1 and T2 relaxation times were missing one copy of the myelin basic protein (MBP) gene. The one patient with normal-appearing white matter and normal white matter T1 and T2 relaxation times possessed two copies of the MBP gene. MRI and molecular genetic data suggest that incomplete cerebral myelination in 18q- is associated with haploinsufficiency of the gene for MBP.
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center at San Antonio, 78284, USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Gay
authors.forename: L J
authors.initials: LJ
authors.lastname: Hardies
authors.forename: R A
authors.initials: RA
authors.lastname: Rauch
authors.forename: J L
authors.initials: JL
authors.lastname: Lancaster
authors.forename: R
authors.initials: R
authors.lastname: Plaetke
authors.forename: B R
authors.initials: BR
authors.lastname: DuPont
authors.forename: J D
authors.initials: JD
authors.lastname: Cody
authors.forename: J E
authors.initials: JE
authors.lastname: Cornell
authors.forename: R C
authors.initials: RC
authors.lastname: Herndon
authors.forename: P D
authors.initials: PD
authors.lastname: Ghidoni
authors.forename: J M
authors.initials: JM
authors.lastname: Schiff
authors.forename: C I
authors.initials: CI
authors.lastname: Kaye
authors.forename: R J
authors.initials: RJ
authors.lastname: Leach
authors.forename: P T
authors.initials: PT
authors.lastname: Fox
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics* / Q000473:pathology; D000293:Adolescent; D001921:Brain / Q000473:pathology*; D001928:Brain Diseases, Metabolic / Q000235:genetics* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000235:genetics* / Q000473:pathology; D002872:Chromosome Deletion; D025063:Chromosome Disorders; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics* / Q000648:ultrastructure; D005260:Female; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D004676:Myelin Basic Protein / Q000172:deficiency / Q000235:genetics*; D009186:Myelin Sheath / Q000502:physiology* / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D013577:Syndrome
chemical_list: D004676:Myelin Basic Protein