Different mutations in the IL1RAPL1 gene, located to the X chromosome, have been discovered in male members of families with intellectual disability (ID) and autism spectrum disorders (ASD).
Most of the mutations lead to the absence of IL1RAPL1 protein production or to a small or truncated form of the protein.
Mutations and deletion of IL1RAPL1 gene are related to different phenotypes (even in the same family and in patients with the same mutation) including different severity of ID, association or not with ASD and other physical features.
IL1RAPL1 mutations are either de novo or are inherited from a carrier mother.
Even if most of the carrier females have normal cognitive skills, there are some cases of mild cognitive impairments or learning difficulties that may be due to a different X-inactivation pattern.
Mutations in the IL1RAPL1 gene are rare; the prevalence of the mutations is unknown.