Rett's disorder is a progressive brain disease that mainly affects girls and can resemble autism.  Normal prenatal and perinatal development occurs. Psychomotor development is normal through the first 5 months after birth and head circumference is normal at birth.

After the period of normal development, characteristics can include:

	Deceleration of head growth is seen between 5 months and 48 months.
	A loss of purposeful hand skills may be seen between 5 months and 30 months.
	Development of stereotyped hand movements such as hand-wringing or hand washing may appear between 5 months and 30 months.
	A loss of social engagement early on, although, social interaction can develop later.
	Poorly coordinated gait or trunk movements.

Rett's also may include severely impaired expressive and receptive language development with severe psychomotor retardation.

To learn more about Rett's disorder click here.