There are phenotypic spectrums of ARX variants ranging from hydranencephaly and lissencephaly (OMIM 300215); Proud syndrome (OMIM 300004); infantile spasms without brain malformations or developmental and epileptic encephalopathy 1 (OMIM 308350); intellectual developmental disorder (OMIM 300419); to Partington syndrome (OMIM 309510)2. The gene discussed is ARX; the disease is lissencephaly spectrum disorders.