A case of Pelizaeus-Merzbacher disease showing increased dosage of the proteolipid protein gene.

Clinical, neuropathological and molecular genetic studies in a 9 month old boy with Pelizaeus-Merzbacher disease are described. The principal clinical features were developmental delay, nystagmus, stridor and seizures. Both brain and spinal cord showed almost complete absence of stainable central myelin, while cranial and spinal root myelin was preserved. Probes for cDNA in the boy and his asymptomatic mother indicated an increase in the dosage of proteolipid protein gene (of at least twofold) compared with controls.