Most scientists agree that there is a genetic basis for autism, with an assortment of environmental factors possibly conspiring with the altered genes to produce the many forms of the disorder. Many believe that genetic analyses will point the way for future research and potential therapies.
The Simons Simplex Collection will supply the groundwork for a different approach to autism genetics. The strategy is based on the premise that new genetic alterations occur in the germ line (sperm or eggs) of one of the parents, but they are not found in other tissues of the parents. Such new or sporadic mutations may account for a large fraction of autism cases. They may also explain why the incidence of autism increases with parental age.
Tischfield said that, in general, there may be several different kinds of genetic deficiencies in autism and that many cases may not be due to mutations that are passed on from generation to generation, as in other disorders , such as cystic fibrosis or hemophilia. Consistent with this, geneticists are finding that in sporadic autism cases, where there are no other affected children, there is a high frequency of relatively large, new DNA deletions that are probably not inherited.
You do not find them in the parents and that is the key, Tischfield said. To find individuals with sporadic mutations the project will seek out families with only one affected child. In a family where several children display autism, there is probably a defect in a gene that is inherited in the usual sense.
Clinicians and scientists working with the Simons Simplex Collection are establishing new and rigorous diagnostic criteria to ensure that the selected individuals represent this sporadic type of autism. Molecular tests will eliminate individuals with other dis
|Contact: Joseph Blumberg|
Rutgers, the State University of New Jersey