a rare genetic neurological disorder that is first recognized in infancy and primarily occurs in girls, but there are rare cases reported in boys as well. Rett syndrome leads to severe impairments, affecting nearly every aspect of the person's life.
Rare, but not alone
Rett syndrome is a rare disease that impacts about 350,000 people worldwide and about 11,000 people in the United States. Rett syndrome is the second most common cause of severe intellectual disability in females and during its period of developmental regression, a substantial proportion of affected individuals meet diagnostic criteria for autism spectrum disorder (ASD).