The NICHD funds and conducts research on disorders that primarily or only affect females. One example of such a disorder is Rett syndrome.
Rett Syndrome
Rett syndrome is a disease caused by a change in the sequence of a single
. This is called a "mutated" gene. The mutation, or change in the gene sequence causes the body to grow or develop differently than it should.
In Rett syndrome, the mutated gene is located on the X
. Girls have two X chromosomes, which means that they can have one mutated gene and one normal gene. Researchers think that this normal "back-up" copy of the gene is what allows the girls to grow in their mothers' wombs and reach birth. Boys, on the other hand, have one X chromosome and one Y chromosome. Their X chromosome contains the mutated gene; they don't have the backup copy. For this reason, boys with Rett syndrome seem to die before they're even born.
Most girls with Rett syndrome grow normally for a time, showing no symptoms of the condition. Then, usually between six months and 18 months of age, their development starts to go backward. They stop talking. They stop using their hands to do things, or they start wringing their hands all the time. Some of these girls lose control of their feet while they're walking. After some time, the girls stop responding to people and things around them.
Because Rett syndrome causes autism-like symptoms, such as poor language skills, repetitive hand motions, and decreased social contact, it is classified as an autism spectrum disorder; that is, Rett syndrome is not autism, but it has features similar to autism. Girls with Rett syndrome may live into their forties, but their lives are not easy. Most girls with Rett syndrome can't care for themselves and need someone to care for them for all their lives.
The NICHD has been researching Rett syndrome for nearly a decade. In 1999, NICHD-supported scientists identified the specific gene that was mutated in Rett syndrome. Some more recent NICHD research suggests that some boys with the Rett syndrome gene may actually survive to be born, but die shortly after birth of a problem that resembles sudden infant death syndrome (SIDS). Other NICHD research has identified the job of the mutated gene in growth and development. These findings and continued research on Rett syndrome on Rett syndrome could someday lead to a cure for this baffling disease.
The NICHD's publications, Rett Syndrome and El Síndrome de Rett (Spanish), provide more detailed information about this condition. You can also contact the International
for information and resources related to Rett syndrome.
