Similarly, alteration in the recycling endosomal processes by mutations in the SLC9A6 sodium exchanger have been associated with Christianson syndrome (MIM 300243), a neurodevelopmental disorder characterized by ID, speech impairment, epilepsy, postnatal microcephaly, truncal ataxia, and hyperactivity43,44. The gene discussed is SLC9A6; the disease is neurodevelopmental disorder.