Rett syndrome

Rett syndrome is a rare genetic neurodevelopmental disorder, almost always affecting girls, in which early development stalls and skills are lost after the first months of life.

It is caused in most cases by mutations in the MECP2 gene on the X chromosome. Infants develop typically for six to eighteen months, then lose purposeful hand use and spoken language, develop repetitive hand-wringing movements, and experience slowed head growth, walking difficulties, breathing irregularities and seizures. Intellectual disability is profound, though social interest often returns after the regression phase.

Diagnosis is based on clinical criteria and confirmed by genetic testing; the condition is managed by a multidisciplinary team addressing seizures, nutrition, scoliosis and communication. A prescription drug approved by the U.S. Food and Drug Administration in 2023 targets the condition itself. Cannabinoids have been examined in small studies for seizures and behavior in Rett syndrome, and the evidence is preliminary.