_:vb50951664 . _:vb50951664 . _:vb50951664 "url:https://www.ncbi.nlm.nih.gov/pubmed/2773936"^^ . _:vb50951664 "url:https://www.ncbi.nlm.nih.gov/pubmed/15627202"^^ . _:vb50951664 . _:vb50951664 "url:https://www.ncbi.nlm.nih.gov/pubmed/3476455"^^ . _:vb50951664 . _:vb50951664 . _:vb50951664 "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."^^ .