This gene is a homeobox-containing gene expressed during development. The expressed protein contains two conserved domains, a C-peptide (or aristaless domain) and the prd-like class homeobox domain. It is a member of the group-II aristaless-related protein family whose members are expressed primarily in the central and/or peripheral nervous system. This gene is thought to be involved in CNS development. Expansion of a polyalanine tract and other mutations in this gene cause X-linked mental retardation and epilepsy.ARX (Aristaless Related Homeobox) is a Protein Coding gene. Diseases associated with ARX include Lissencephaly, X-Linked 2 and Epileptic Encephalopathy, Early Infantile, 1. Among its related pathways are Ectoderm Differentiation. GO annotations related to this gene include chromatin binding and transcriptional repressor activity, RNA polymerase II distal enhancer sequence-specific binding. An important paralog of this gene is RAX.