Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder characterized by dysmyelination of the central nervous system (CNS) caused by mutations in the proteolipid protein (PLP) gene. PLP is located at Xq22 and its mutation result in abnormal expression or production of PLP, the most abundant protein in CNS myelin. We present a case of PMD in the 7-year-old boy with nystagmus, ataxia, spastic quadriplegia and severe psychomotor delay. His brain MRI revealed totally dysmyelinated white matter

involving entire supratentorial region, atrophic change, and overaccumulation of the iron in both basal ganglia. He also showed soft-tissue contractures of the hip adductors, associated hip dislocations and equinovarus foot deformities due to severe spasticity of lower extremities. Orthopaedic surgery was performed on both hips. Antispastic medication and physical therapy were maintained for reduction of spasticity. We report this case with the review of literatures. (J Korean Acad Rehab Med 2002; 26: 108-112)