Rett syndrome is genetic in origin, and is among the most common genetic cause of profound intellectual and physical disability in girls, with an estimated prevalence of seven to ten cases per 100,000 females.

Children who have Rett's syndrome seem to develop normally for the first 6-18 months, at which point there is a noticeable change in the child's behavior and some regression or loss of abilities, especially in gross motor skills such as walking and moving.

This is generally followed by a more obvious loss in abilities such as speech, reasoning and hand movements. Repetitive movements or gestures such as constant hand-wringing or hand washing are also common.

  • Normal development during first months of infancy
  • Hypotonia (floppy extremities) is frequently the first manifestation
  • Head growth begins slowing (deceleration in head circumference) at approximately 5-6 months of age
  • Overall developmental regression
  • Language development, both expressed and understood, is severely impaired
  • Loss of meaningful hand use, replaced by movements such as hand wringing or placing the hand in the mouth
  • Seizures (seen in about 1/3rd of patients)
  • Intermittent hyperventilation with a disorganized breathing pattern