Christianson Syndrome

Christianson syndrome is an X-linked syndrome associated with intellectual disability, microcephaly, seizures, ataxia, and absent speech. Many individuals with this condition have a happy demeanor with frequent smiling and unprovoked laughter, similar to those with Angelman syndrome. Christianson syndrome is caused by mutations in the SLC9A6 gene, which is located within the q24-q27 interval of the X chromosome. There appears to be a range of phenotypes in carrier females, from intellectual disability to absence of symptoms.