Intellectual Developmental Disorder, X-Linked, Syndromic, Christianson Type, also known as mental retardation, x-linked, syndromic, christianson type, is related to christianson syndrome and microcephaly, and has symptoms including ataxia, ophthalmoplegia and sleep disturbances. An important gene associated with Intellectual Developmental Disorder, X-Linked, Syndromic, Christianson Type is SLC9A6 (Solute Carrier Family 9 Member A6). Affiliated tissues include eye and brain.