title: [A case of congenital hypomyelination neuropathy with type I Chiari malformation and mental retardation].
abstract: A four-year old boy with congenital hypomyelination neuropathy (CHMN) had mental retardation and a tic disorder, the latter commencing at 2 years of age. The diagnosis of CHMN was confirmed by electron microscopy of his biopsied sural nerve which showed loss of large myelinated fibers, decreased density of myelinated fibers, many naked axons and atypical onion bulb formation. MR imaging showed type I Chiari malformation in the absence of clinical signs attributable to it. Auditory brainstem response (ABR) showed delayed wave I peak latency, prolonged I--III interpeak latency, broad wave II duration and normal III--V interpeak latency, suggesting abnormal peripheral and normal central myelination. The association of CHMN with mental retardation. Chiari malformation and tic disorder has never been reported, the significance of which remained unclear.
authors.affiliation: Department of Child Neurology, National Center Hospital for Mental, Nervous and Muscular Disorders, Kodaira, Tokyo.
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Sugai
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: S
authors.initials: S
authors.lastname: Hirano
authors.forename: S
authors.initials: S
authors.lastname: Hanaoka
authors.forename: T
authors.initials: T
authors.lastname: Hashimoto
authors.forename: I
authors.initials: I
authors.lastname: Nonaka
authors.forename: T
authors.initials: T
authors.lastname: Nagai
mesh_terms: D001139:Arnold-Chiari Malformation / Q000150:complications*; D002675:Child, Preschool; D003711:Demyelinating Diseases / Q000151:congenital* / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem; D006801:Humans; D008607:Intellectual Disability; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D013981:Tic Disorders / Q000150:complications