At 15 months, Rett syndrome robbed Chelsea of the only word she ever learned to say: "duck," for the favorite toy she soon became unable to play with.
She cried, inconsolably, for a very, very, long time. When her parents tried to hold her, she bit them and wriggled away. She'd already become unable to sit up or stand by herself. Soon she no longer responded to her name.
"Little things she did, like play patty-cake or wave bye-bye, she could not do anymore," Chelsea's mother, Monica Coenraads, tells WebMD. "She was only happy in her crib, with the lights off, playing obsessively with this little silk blanket."
Now there's new hope for Chelsea and other people with Rett syndrome — including more than 20,000 Americans. That hope may also extend to some other people with autism, and to some cases of learning disability, retardation, and perhaps even schizophrenia.
The mutant MECP2 gene that causes Rett syndrome does not cause permanent brain damage, new mouse studies show. When MECP2 gene function is restored, mice crippled by Rett-like symptoms start running around just like normal mice.
The hope: Rett syndrome may be reversible in humans.
The studies come from the lab of Adrian Bird, Ph.D., a professor at Scotland's University of Edinburgh and chairman of the scientific board of the Rett Syndrome Research Foundation. Bird in 1990 discovered the MECP2 gene.
"This changes the mindset. It replaces pessimism by optimism," Bird tells WebMD. "It does not suggest an actual treatment. But now, with a spring in their step, people can move forward and look for a treatment."
"The findings are extraordinary, and are of relevance not only to Rett syndrome but to a much broader class of disorders, including autism and schizophrenia," Baylor University researcher Huda Zoghbi, MD, said in a news release. It was Zoghbi who in 1999 found that MECP2 mutations cause Rett syndrome.
Bird and colleagues report their findings in the Feb. 8 issue of the online journal Sciencexpress.
Rett syndrome is part of the spectrum of autism disorders.
Symptoms usually appear at age 6 to 18 months. As in other autism spectrum disorders, children withdraw socially. Like Chelsea, they often cry for months on end. Unlike kids with other autism disorders, Rett-syndrome children often begin constant, compulsive hand wringing. They lose any language and motor skills they may have learned.
Eventually, their hands become useless, as the ability to organize voluntary movements goes away. Chewing, swallowing, and even breathing can be a problem. Tremors are common; some kids have seizures.
The gene responsible for Rett syndrome appears only on the X chromosome. Boys have only one X chromosome. If they inherit a mutant MECP2 gene, they usually die as infants.
But girls have two X chromosomes. If they inherit the mutant gene from one parent, they almost always get a good copy of the gene from the other parent. X-gene expression is random in females, so girls with a single copy of the gene still have some MECP2 gene function. That rescues girls from death. "But the price of the rescue is Rett syndrome," Bird says.
Today, Chelsea is confined to a wheelchair. She must be tube-fed. She cannot use her hands or make any purposeful movements, and she suffers daily seizures.