The essential feature of Rett’s disorder is the development of multiple specific deficits in a child 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. Head circumference at birth is also within normal limits.

Rett’s disorder is typically associated with severe or profound mental retardation.

Specific Symptoms of Rett’s Disorder

All of the following:

  • Apparently normal prenatal and perinatal development
  • Apparently normal psychomotor development through the first 5 months after birth
  • Normal head circumference at birth

Onset of all of the following after the period of normal development:

  • A deceleration of head growth between ages 5 and 48 months
  • Loss of previously acquired purposeful hand skills between ages 5 and 30 months with the subsequent development of stereotyped hand movements (e.g., hand-wringing or handwashing)
  • Loss of social engagement early in the course (although often social interaction develops later)
  • Appearance of poorly-coordinated gait or trunk movements
  • Severely-impaired expressive and receptive language development with severe psychomotor retardation