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Seven Facts about Rett Syndrome
1. Rett syndrome is a genetic disorder. The cause of Rett syndrome is a mutation in the MECP2 gene, which codes for the protein methyl cytosine binding protein 2. This protein plays an important role in brain development, and also affects the expression of several other genes.
2. Rett syndrome is not inherited. Although it is a genetic disorder, fewer than 1% of those suffering from Rett syndrome have a family history of the condition. Instead, it is caused by a spontaneous mutation of the MECP2 gene. In some cases, there are women who carry the mutated gene and do not have symptoms.
3. Rett syndrome occurs almost exclusively in girls. The MECP2 gene is located on the X chromosome, one of the two sex chromosomes. Girls have two X chromosomes, but since the mutation is dominant, only one of the X chromosomes needs to have the mutation for the condition to appear. If the second X chromosome is normal, the symptoms may not be as severe because the normal X chromosome can compensate. Boys have one X and one Y chromosome. If the MECP2 mutation occurs on the single X chromosome in a boy, the problems are often so severe that the child dies soon after he is born.
4. Rett syndrome is a neurodevelopmental disorder. This condition affects growth, speech and motor function, with symptoms ranging from mild to severe. Many of the symptoms in the early stages of Rett syndrome are similar to those of autism. Some symptoms include the loss of ability to move the hands purposefully, characteristic repetitive hand motions such as wringing or washing, difficulty walking, slowed growth of the brain and head, cognitive disabilities, sleep problems, loss of ability to speak, and seizures. There may also be breathing difficulties such as apnea, hyperventilation and swallowing air.
5. Rett syndrome appears in four stages.
- Stage I- Early onset, between 6 and 18 months of age when symptoms of decreased eye contact and delayed motor skills begin to appear.
- Stage II- Rapid destructive stage, usually occurring between one and four years of age. The child loses language skills and purposeful hand movement, and exhibits characteristic washing, wringing or tapping hand movements, breathing and motor difficulties, and slowed growth of the head.
- Stage III- Plateau or pseudo-stationary stage, beginning between the ages of two and ten. Motor difficulties and seizures are common, but communication and alertness may improve. This stage may last for many years.
- Stage IV- Late motor deterioration stage, in which mobility is reduced
6. Rett syndrome is diagnosed using three types of clinical criteria: essential, supportive and exclusion.
- Essential criteria are symptoms that are required for a positive diagnosis of Rett syndrome. They include developing normally for the first 6 to 18 months, normal head size at birth but rate of growth slowing by the age of 4 years, impaired language, abnormal way of walking such as walking on toes or with stiff legs, and characteristic hand movements.
- Supportive criteria are symptoms that may appear in some cases, including seizures, spasticity, breathing problems, scoliosis, small hands and feet, teeth grinding, poor circulation of legs and feet, difficulty chewing and swallowing, sleep disorders, abnormal EEG, and agitation and irritability.
- Exclusion criteria are used to rule out the disorder. Children with these symptoms do not have Rett syndrome. Exclusion criteria include enlarged organs, loss of vision due to atrophy of the retina, small head at birth, metabolic or degenerative disorders, or retarded growth in the womb.
7. Treatment for Rett syndrome is based on management of symptoms. Our final fact about Rett syndrome is that medication might be necessary for seizures and breathing problems. Physical therapy can help increase mobility, and braces or splints may be necessary for correcting scoliosis and hand movements. Occupational therapy may be useful to improve activities such as eating and dressing.