Rett Syndrome (RTT) is a neurodevelopmental disorder that causes significant developmental regression. It is one of the most physically disabling of the Autism Spectrum Disorders. RTT is rare and is believed to affect 1 in 10,000 females.
First recognized in 1966 by Andreas Rett, RTT was not generally accepted until 1983. In 1999, Dr. Huda Zoghbi located the gene responsible for Rett Syndrome.
RTT is caused by random mutations in the gene MECP2, located on the X chromosome. The MECP2 gene contains instructions for the synthesis of a protein called methyl cytosine binding protein 2 (MeCP2), which is needed for brain development and acts as a biological switch for gene expression. When the MECP2 gene doesn’t function properly and insufficient or abnormal amounts of the protein are produced, it can cause other genes to be abnormally expressed.
Less than 1% of cases are familial, meaning that the faulty gene is rarely inherited. Since the gene is located on an X chromosome, RTT is almost exclusive to females; boys who develop the mutation usually die shortly after birth.
Between six and 18 months of age is when the symptoms usually begin. One of the first symptoms is a slowing of head growth and a loss of muscle tone. Other symptoms include loss of acquired speech and motor skills, repetitive hand wringing or other movements, breathing difficulties (apnea and hyperventilation), seizures (80% have epilepsy), prolonged toe walking, teeth grinding, body rocking, and sleep problems. In most cases, there is a regression in cognition, behavior, social, and motor skills throughout their lifetime. Apraxia, the inability to perform motor functions, is probably the most severely disabling feature, as it interferes with every body movement.
Four Stages of RTT
The first stage is called Early Onset, and usually takes place in the six to 18 month age range. Symptoms, such as a delay in gross motor skills, may be vague and therefore the diagnosis is often overlooked. This stage usually lasts a few months but can extend to over a year.
The second stage is called Rapid Destructive. This usually occurs in the one to four year age range. Symptoms include slowed head growth, loss of social interaction and communication, loss of purposeful hand skills, and irregular breathing.
The third stage is the Plateau stage. This stage usually occurs in females aged two to ten years. The majority of those affected with RTT remain in this stage. Symptoms can include apraxia, seizures, and severe motor problems. In some cases, communication skills may improve in this stage.
The fourth stage is called Late Motor Deterioration. This stage can last for years or even decades. Symptoms include reduced mobility, scoliosis, and muscle weakness.
Diagnosis & Testing
There is currently no cure for Rett Syndrome; however, there are treatments available to help improve the quality of life of the individual, such as physical therapy, speech therapy, and occupational therapy. Genetic testing can confirm a diagnosis in approximately 80% of cases.
Researchers are currently exploring how bone marrow transplants might affect symptoms of RTT.
Little is known about long-term prognosis and life expectancy. Most individuals with RTT survive into adulthood but are wheelchair bound. They often rely on feeding tubes, are unable to communicate, and require round-the-clock care.
For more information, check out the International Rett Syndrome Foundation or the Rett Syndrome Research Trust. To learn more about RTT from a parent's perspective, check out the blog My Silent Angel's Fight.
For a more visual experience, check out the video library at Rett TV.