Mondo Description Pelizaeus-Merzbacher disease (PMD) is an X-linked leukodystrophy characterized by developmental delay, nystagmus, hypotonia, spasticity, and variable intellectual deficit. It is classified into three sub-forms based on the age of onset and severity: connatal, transitional, and classic PMD.

Uniprot Description A X-linked recessive disorder of the central nervous system in which myelin is not formed properly. Clinically characterized by nystagmus, spastic quadriplegia, ataxia, and developmental delay.

Disease Ontology Description A hypomyelinating leukodystrophy characterized by impaired myelin formation, nystagmus, spastic quadriplegia, ataxia, and developmental delay that has_material_basis_in mutation in the PLP1 gene on chromosome Xq22.