Even a minimal understanding of the genetic basis of autism would be of great value. For example, researchers could transfer the alleles associated with autism from humans to mice, engineering them to be genetically susceptible to the disorder. By exposing these mice to substances suspected of increasing the risk of autism, we would be able to study the interaction of environmental factors with genetic background and perhaps compile an expanded list of substances that women need to avoid during early pregnancy. What is more, by examining the development of these genetically engineered mice, we could learn more about the brain damage that underlies autism. If researchers can determine exactly what is wrong with the brains of people with autism, they may be able to suggest drug therapies or other treatments that could ameliorate the effects of the damage.
Devising a genetic test for autism -- similar to the current tests for cystic fibrosis, sickle cell anemia and other diseases -- would be a much more difficult task. Because so many genes appear to be involved in the disorder, one cannot accurately predict the odds of having a child with autism by simply testing for one or two variant alleles in the parents. Tests might be developed, however, for the siblings of people with autism, who often fear that their own children will inherit the disorder. Clinicians could look for a set of well- established genetic risk factors in both the family member with autism and the unaffected sibling. If the person with autism has several high-risk alleles, whereas the sibling does not, the sibling would at least be reassured that his or her offspring would not be subject to the known risks within his or her family.
Nothing will make the search for autism's causes simple. But every risk factor that we are able to identify takesaway some of the mystery. More important, new data spawn newhypotheses. Just as the thalidomide results drew attention to the brain stemand to the HOXA1 gene, new data from developmental genetics,behavioral studies, brain imaging and many other sources can be expected toproduce more welcome shocks of recognition for investigators of autism.In time, their work may help alleviate the terrible suffering caused by the disorder.
PATRICIA M. RODIER is professor of obstetrics and gynecology at the University of Rochester. She has studied injuries to the developing nervous system since she was a postdoctoral fellow in embryology at the University of Virginia, but she began to investigate autism only after hearing the results of the thalidomide study. Rodier has assembled a group of scientists from many disciplines at six institutions to study the genetic and environmental causes of the disorder and says that working with experts from other fields is rejuvenating.
AUTISM IN THALIDOMIDE EMBRYOPATHY: A POPULATION STUDY. K. Strornland, V. Nordin, M. Miller, B. Akerstrom and C. Gillberg in Developmental Medicine and Child Neurology, Vol. 36, No. 4, pages 35 1Z356; April 1994.
EMBRYOLOGICAL ORIGIN FOR AUTISM: DEVELOPMENTAL ANOMALIES OF THE CRANIAL NERVE MOTOR NUCLEI. P. M. Rodier, J. L. Ingram, B. Tisdale, S. Nelson and J. Romano in Journal of Comparative Neurology, Vol. 370, No. 2, pages 247Z261; June 24, 1996.
THINKING IN PICTURES: AND OTHER REPORTS FROM MY LIFE WITH AUTISM. Temple Grandin. Vintage Books, 1996.
More information on autism is available at the Web page of the National Alliance for Autism Research at www.naar.org