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 genetic changes 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.