Most infants with Rett syndrome seem to grow and behave normally for the first six months. After that, signs and symptoms start to appear. The most pronounced changes generally occur at 12 to 18 months of age, over a period of weeks or months. Symptoms and their severity can vary greatly from child to child.

Rett syndrome (RTT, MIM#312750) is a neurodevelopmental disorder that is classified as an autism spectrum disorder. Clinically, RTT is characterized by psychomotor regression with loss of volitional hand use and spoken language, the development of repetitive hand stereotypies, and gait impairment.

These ‘non-seizure’ events included episodes of motor activity, such as twitching, jerking, head turning, falling forward, and trembling, as well as episodes of staring, laughing, pupil dilatation, breath holding and hyperventilation.

The Rett Spectrum Clinic a specialty clinic designed to care for and support children with Rett Syndrome and Rett Related Disorders including MECP2 duplications, CDKL5, and FOXG1. The clinic is a collaboration between Washington University School of Medicine and St. Louis Children’s Hospital.

Although there is no cure for Rett syndrome, treatments are directed toward symptoms and providing support, which may improve the potential for movement, communication and social participation.

Prenatal diagnosis for Rett syndrome involves DNA testing to find out whether the developing fetus has a mutation in the MECP2, CDKL5, and FOXG1 genes. Rett syndrome mostly occurs as a result of a de-novo mutation, meaning that the defect is not inherited from the parents but appears spontaneously.

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.

Although Rett syndrome is a genetic disorder, less than 1 percent of recorded cases are inherited or passed from one generation to the next. Most cases are sporadic, which means the mutation occurs randomly, and are not inherited. A few families have been described with more than one affected family member.

Rett syndrome occurs almost exclusively in girls. The incidence of Rett syndrome in the United States is estimated to be 1 in 10,000 girls by age 12.

Between 3 months and 3 years of age, though, they stop developing and even lose some skills. Symptoms include Rett syndrome has no cure. You can treat some of the symptoms with medicines, surgery, and physical and speech therapy. Most people with Rett syndrome live into middle age and beyond. They will usually need care throughout their lives.

Prenatal testing is available for families with an affected daughter who has an identified MECP2 mutation. Since the disorder occurs spontaneously in most affected individuals, however, the risk of a family having a second child with the disorder is less than 1 percent.

The discovery of the main Rett syndrome gene (MECP2) in 1999 provides a basis for further genetic studies and enables the use of recently developed animal models such as transgenic mice which are deficient in MECP2. These mice have neurologic abnormalities that can be reversed by activating the MECP2 gene later in life.

Another unique trait in ASD is that children on the spectrum tend to prefer objects to people. This is opposite of RTT. With Rett syndrome, the preference is typically towards people. Children with ASD usually reject physical affection and those with RTT typically enjoy the attention.