Facts First

  Prevalence:                    Occurs only in females.  Data is limited, but occurs much less frequently 
                                           than Autistic Disorder

  Characteristics:            The essential feature of Rett's Disorder is the development of multiple 
                                           specific deficits following a period of normal functioning after birth.  
                                           Individuals have an apparently normal prenatal and perinatal period with 
                                           normal psychomotor development through the first 5 months of 
                                           life.  Between ages 5 and 48 months, head growth decelerates.  There is a 
                                           loss of previously acquired purposeful hand skills between ages 5 and 30 
                                           months, with subsequent development of characteristic stereotyped hand 
                                           movements resembling hand-wringing or hand washing.  Interest in the 
                                           social environment diminishes in the first few years after the onset of the 
                                           disorder.  Problems develop  in the coordination of gait or trunk movements.

                                           Onset prior to age 4.

  Causes:                         No known cause.  Preliminary data suggest that a genetic mutation is the 
                                           cause of some cases of Rett's Disorder.