_:vb50943626 . _:vb50943626 . _:vb50943626 . _:vb50943626 . _:vb50943626 "url:https://www.ncbi.nlm.nih.gov/pubmed/8012387"^^ . _:vb50943626 "A hereditary spastic paraplegia that has_material_basis_in mutation in the PLP1 gene on chromosome Xq22.2."^^ . _:vb50943626 .