115 Rett’s Disorder (299.80)
Introduction
- First discovered in 1966 by an Austrian physician (Harris, Glasberg, & Ricca).
- Noticed two girls in his waiting room exhibiting identical hand mannerism.
- Ultimately, he identified similar hand movements among 20 other girls diagnosed with mental retardation.
- Characteristically defined as a pattern of regression beginning at 5-18 months old to include social, language, motor, and cognitive development (Hoffman, 2009).
- Rett’s disorder is second to Down’s syndrome as a cause of mental retardation in females (Hoffman, 2009).
- Characteristically, only found in females due to being linked with the X chromosome that encodes Methyl-CpG binding protein-2 (MECP2).
- MECP2 involved in the regulation of expression of other genes during development.
- Mutations in MECP2 reported in 87% of females with classical Rett’s disorder
- Mutations in MECP2 reported in 50% of females with variant of the disorder
- Mutations in MECP2 found to be lethal in males.
- Characteristically, only found in females due to being linked with the X chromosome that encodes Methyl-CpG binding protein-2 (MECP2).
DSM-IV-TR criteria
- A. All of the following:
- 1. apparently normal prenatal and perinatal development
- 2. apparently normal psychomotor development through the first 5 months after birth
- 3. normal head circumference
- B. Onset of all of the following after the period of normal development:
- 1. deceleration of head growth between ages 5 months and 48 months
- 2. 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 hand washing)
- 3. loss of social engagement early in the course (although often social interaction develops later)
- 4. appearance of poorly coordinated gait or trunk movements
- 5. severely impaired expressive and receptive language development with severe psychomotor retardation
Associated features
Children diagnosed with Rett’s Disorder present normal development and functioning until onset between 5 and 48 months. Rett’s Disorder has typically been associated with Severe or Profound Mental Retardation. There may be an increased frequency of EEG abnormalities in this particular population of individuals. Also, seizure disorder is seen in individuals with Rett’s Disorder. Research suggests that the cause of Rett’s Disorder may be a genetic mutation. Rett’s Disorder is a genetic disorder of developmental arrest or failure of brain maturation. This is thought to happen when subsets of neurons and their synapses are disrupted during a very important time of brain development. This deviation occurs at the end of pregnancy or in the first few months of life during the important time of synapse development. A deceleration of head growth between ages 5 and 48 months is one symptom. Others are loss of previously acquired purposeful hand skills between ages 5 and 30 months, loss of social engagement early