What is Rett syndrome?

Rett syndrome is a childhood neurodevelopmental disorder characterized by normal early development followed by loss of purposeful use of the hands, distinctive hand movements, slowed brain and head growth, gait abnormalities, seizures, and mental retardation. It affects females almost exclusively.

The disorder was identified by Dr. Andreas Rett, an Austrian physician who first described it in a journal article in 1966. It was not until after a second article about the disorder was published in 1983 that the disorder was generally recognized.

Rett syndrome is caused by mutations (structural alterations or defects) in the MECP2 (pronounced meck-pea-two) gene, which is found on the X chromosome (see section on "Who gets Rett syndrome" for a discussion of the importance of the involvement of the X chromosome). Scientists identified the gene — which is believed to control the functions of several other genes — in 1999. The MECP2 gene contains instructions for the synthesis of a protein called methyl cytosine binding protein 2 (MeCP2), which acts as one of the many biochemical switches that tell other genes when to turn off and stop producing their own unique proteins. Because the MECP2 gene does not function properly in those with Rett syndrome, insufficient amounts or structurally abnormal forms of the protein are formed. The absence or malfunction of the protein is thought to cause other genes to be abnormally expressed, but this hypothesis has not yet been confirmed.

Rett syndrome affects one in every 10,000 to 15,000 live female births. It occurs in all racial and ethnic groups worldwide. Prenatal testing is available for families with an affected daughter who has an identified MECP2 mutation.

There is no cure for Rett syndrome. Treatment for the disorder is symptomatic — focusing on the management of symptoms — and supportive, requiring a multidisciplinary approach. Medication may be needed for breathing irregularities and motor difficulties, and antiepileptic drugs may be used to control seizures.

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