A neurological disorder affecting 1 in 10,000 to 1 in 23,000 females

Rett Syndrome is caused by the MECP2 gene on the X chromosome. Children with Rett Syndrome develop normally until 6 to 18 months of age. This is followed by a period of regression that leads to a loss of speech, motor and hand skills and physical disabilities including:

Development of repetitive hand movements

Possible EEG (electroencephalographic) abnormalities:
irregular breathing
seizures
scoliosis
teeth grinding
chewing and/or swallowing difficulties
poor weight gain
abnormal sleeping patterns
small feet

Apraxia (dyspraxia) -- the inability to program the body to perform motor movements -- is the most severely handicapping aspect of Rett Sydrome. Children with Rett Syndrome often have attractive features and penetrating eyes.