Male individuals with Christianson syndrome have moderate to severe developmental delay / intellectual disability, epilepsy, regression in early childhood, mutism, postnatal microcephaly, hyperkinesis, truncal ataxia, and cerebellar atrophy. Secondary symptoms include autistic behaviour, ophthalmoplegia (strabismus), gastroesophageal reflux disease, hypotonia, low weight for age group, difficulty sleeping, and hypoalgesia.
Females who carry a defective variant of SLC9A6are generally asymptomatic but in exceptional cases can exhibit moderate intellectual disability, delays in speech and language acquisition, and psychiatric illnesses, including separation anxiety disorder, difficulty forming emotional attachments to others, uncooperative behaviour and attention deficit/hyperactivity disorder (ADHD).
SLC9A6