_:vb50940943 "url:https://www.ncbi.nlm.nih.gov/pubmed/18469812"^^ . _:vb50940943 "A developmental and epileptic encephalopathy characterized by onset of tonic seizures in early infancy and severely impaired psychomotor development that has_material_basis_in heterozygous mutation in the STXBP1 gene on chromosome 9q34.1."^^ . _:vb50940943 . _:vb50940943 . _:vb50940943 . _:vb50940943 . _:vb50940943 . _:vb50940943 "url:https://pubmed.ncbi.nlm.nih.gov/19557857/"^^ .