Psychosis and autism without functional regression in a patient with Kleefstra syndrome.

Kleefstra syndrome is a rare genetic disorder caused by haploinsufficiency of the euchromatic histone lysine methyltransferase 1 (EHMT1) gene. It is characterized by a variety of dysmorphic features, comorbid medical issues, and developmental delays/intellectual disability. Neuropsychiatric symptoms may also occur, including autistic features and psychosis, and are often accompanied by functional regression.