Intellectual Developmental Disorder, X-Linked 21, also known as mental retardation, x-linked 34, is related to non-syndromic x-linked intellectual disability 21 and neutropenia, and has symptoms including seizures An important gene associated with Intellectual Developmental Disorder, X-Linked 21 is IL1RAPL1 (Interleukin 1 Receptor Accessory Protein Like 1). Affiliated tissues include brain and whole blood, and related phenotypes are joint hypermobility and intellectual disability, moderate