Rett's disorder

Definition:

An inherited disorder that affects only females; the syndrome causes mental retardation and developmental degeneration.

Causes, incidence, and risk factors:

Rett's disorder is inherited as an X-linked trait. It affects only females. The exact cause of the trait is unknown, but it has been linked with a metabolic disorder. The prevalence of Rett's disorder is 6 to 7 cases per 100,000 females. During the first five months the child is developmentally on track. From six months to two years the child's condition deteriorates.