NORD gratefully acknowledges Jeffrey L. Neul, MD, PhD, Chief of Division of Child Neurology, University of California, San Diego and Rady Children’s Hospital San Diego, for assistance in the preparation of this report.
Synonyms of Rett Syndrome
- classic Rett syndrome
- variant (atypical) Rett syndrome
Subdivisions of Rett Syndrome
Rett syndrome is a progressive neurodevelopmental disorder that almost exclusively affects females. Only in rare cases are males affected. Infants with Rett syndrome generally develop normally for about 7 to 18 months after birth. At this point, they lose previously acquired skills (developmental regression) such as purposeful hand movements and the ability to communicate. Additional abnormalities occur including impaired control of voluntary movements (ataxia) and the development of distinctive, uncontrolled hand movements such as hand clapping or rubbing. Some children also have slowing of head growth (acquired microcephaly), Affected children often develop autistic-like behaviors, breathing irregularities, feeding and swallowing difficulties, growth retardation, and seizures. Most Rett syndrome cases are caused by identifiable mutations of the MECP2 gene on the X chromosome and can present with a wide range of disability ranging from mild to severe. The course and severity of Rett syndrome is determined by the location, type and severity of the MECP2 mutation and the process of random X-inactivation (see Causes section below). Therefore, two girls of the same age with the same mutation can appear significantly different.
Rett syndrome was first described in the medical literature by an Austrian physician named Andreas Rett in 1960s. Many researchers now consider Rett syndrome as part of a spectrum of disease relating to mutations of the MECP2 gene. This spectrum, sometimes referred to as MECP2-related disorders, includes classic Rett syndrome, variant Rett syndrome, MECP2-related severe neonatal encephalopathy, and PPM-X syndrome. Another disorder, MECP2 duplication syndrome, has recently been described in the medical literature. This disorder is caused by duplicated material involving the MECP2 gene on the X chromosome.
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NORD Member Organizations
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