Understanding, Recognizing, and Treating Rett Syndrome.

Formerly thought to be a neurodegenerative disease, Rett syndrome (RS) is a neurodevelopmental arrest of the brain that almost exclusively affects females and occurs in a variety of racial and ethnic groups worldwide. RS begins in late infancy and is characterized by autistic and dementia-like behavior, ataxia, and purposeless hand movements. Its cause and mode of transmission are unknown in over 90% of cases; however, there is strong and convincing evidence that genetic factors play a major role. The reported incidence varies, but in the US, as many as one quarter to one third of female children in mental wards/institutions may be affected. RS has been mistaken for numerous other conditions, including autism, cerebral palsy, and mental retardation, but the clinical picture is unique: No other condition has a period of rapid deterioration followed by apparent stabilization or even improvement in autistic features, eye contact, seizure activity, and hand stereotypies. The diagnosis is supported by deceleration of head growth, evidence of neurologic regression with associated neurologic signs, and purposeless hand stereotypies, with a clinical history of developmental regression. The differential diagnosis often involves ruling out syndromes with similar signs of neurodevelopmental arrest--for example, meningitis or encephalitis; chromosomal disorders such as Angelman's syndrome and Prader-Willi syndrome; metabolic disorders such as ornithine carbamoyltransferase deficiency; disorders of organic acids and amino acids; neurovisceral storage diseases; mitochondrial cytopathy; and Batten disease, or infantile neuronal ceroid lipofuscinosis. Management encompasses a comprehensive medical, therapeutic, educational, and psychosocial approach, best provided through a team in collaboration with the community agencies that serve families and children with special needs.