A message about Rett Syndrome, one of the pervasive developmental disorders (which include autism), has come to me from Theresa Barlotta, the mother of a Rett Syndrome daughter. Theresa was one of the parents who helped designate October 20 as Rett Syndrome Awareness Day in New Jersey, and she has asked everyone to help communicate information about Rett Syndrome to other people.
Rett Syndrome is a genetically-caused disorder seen almost exclusively in girls. The gene whose dysfunction causes the syndrome was identified about ten years ago, and that discovery made it possible to find some possible mechanisms causing the girls' problems and to envision ways of treating the condition. Boys with the same genetic problems generally die from respiratory problems very early in life, so it's not well known how their behavior and development would be affected if they survived, nor is it clear whether treatments for the Rett girls' problems would help more boys survive.
Rett Syndrome girls appear healthy in the early months, but as toddlers they begin to regress in development and lose ability in language and social ability. They become irritable and wring their hands in a stereotyped way. (This hand-wringing movement and other upper-body movements like "squeezing" the trunk with the arms are not restricted to Rett Syndrome, by the way, but are found in some other genetically-caused problems, while other involuntary arm movements may be caused by non-genetic brain damage). Like all living children, Rett Syndrome girls continue to grow and develop, but they have serious cognitive problems as well as abnormal breathing and movement patterns.
The early development of Rett Syndrome girls resembles that of autistic children in many ways, including their social and language problems. It's especially significant that in both cases the children appear normal early on but seem to change rather suddenly, as if something in the environment has harmed them. However, it's clearly the case that a specific genetic problem causes Rett Syndrome. Researchers have found a strain of mice with a genetic make-up that causes some outcomes similar to Rett Syndrome, such as odd movement patterns. These mice also have high levels of stress hormones, which could possibly make them unusually vulnerable to subtle changes in the environment. Geneticists can manipulate the mouse gene and turn it "on" or "off", thus either causing or curing the behavioral effects, but this is not yet possible with human beings.
Rett Syndrome girls are presently treated by speech therapists and others trained to intervene in developmental problems. Research is currently being done to explore the role of growth factors as treatment for abnormal brain development patterns, as well as on the functions of a drug that is used in cough medicine and which affects the brain chemical glutamate. Other research is examining the connections between Rett Syndrome and seizure disorders. One study is trying to establish the "natural history" of Rett Syndrome-- the events that could be expected to occur as Rett girls continue to develop and get older-- and the quality of life they experience. (These facts, which you might expect to be well understood, are not thoroughly known because diagnosis of the syndrome by genetic means has only been possible for about 10 years.)
For further information about Rett Syndrome, you can go to the web site of the International Rett Syndrome Foundation, www.rettsyndrome.org, or you can look at a helpful article from a couple of years ago ( Miller, G. [2006]. Getting a read on Rett syndrome. Science, Vol. 314, pp. 1536-1537).
While the obvious concern of parents like Theresa Barlotta is to find a cure for their Rett Syndrome daughters, the research on this syndrome also opens the door for fruitful investigation of other pervasive developmental disorders and especially of autism. The discovery of an animal model for the study of Rett Syndrome was a critical step in understanding how the genetic factors functioned and in demonstrating that the disorder could be reversed in mice. Of course, this critical step was only a first step, as mice (and even more complicated animals) do not have the language and social abilities that make us human beings, and that have such an obvious effect when they are missing. Finding that the mice had increased levels of stress hormones seems to provide an interesting parallel to human life, of course, but raises many more questions than it answers: do the increased levels affect brain development, for example, or do the problems in brain development cause stress that changes stress hormone levels?
Although we don't have many of the answers yet, we can all be of a little help by making sure that people understand the nature of this genetic syndrome and its effects on development. If you're a teacher, you might consider how you could bring this topic into your instruction on October 20.
