NEW YORK — Just published findings from Harvard Medical School and other U.S. institutions have shed new light on the genetic basis for autism.
Carried out in collaboration with researchers and families from Jordan, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, Turkey and the United Arab Emirates, the research offers hope that this new understanding will allow a faster method of finding a cure for this mystifying and isolating disease.
Middle East countries were chosen for the research locations because of the number of large families and the tendency of cousins to marry each other. Such conditions increase the probabilities of finding rare genes.
The researchers thus chose 88 families with a history of frequent marriages between cousins and high incidences of autism. They then compared the DNA of members of the same family to look for recessive mutations (alterations of the DNA sequence.) In these kinds of mutations, both the mother and the father may be healthy, but each carries a recessive gene for a disease. The child who inherits the defective gene from both parents is the one who gets sick.
Unlike with diseases such as cystic fibrosis, a growing number of genes has been associated with different forms of autism. The researchers found that large pieces of DNA in some families — which varied among them and affected at least six different genes — play a role in autism. What made this finding particularly interesting is that all of the affected genes seem to be part of a special network involved in a person’s learning.
There was an additional bonus to that discovery. Those pieces of DNA that were not expressed were not lost, but rather had nonfunctioning on-off switches. The switches were “off” for the genes leading to autism.
The finding could have momentous consequences for the treatment of the disease and related disorders. The trick would be to find those elements that switch “on” the affected genes.
As Dr. Christopher Walsh, chief of genetics at Children’s Hospital in Boston, who led the study stated, “It gives us the potential, in the long run, to develop therapies that may be able to reactivate those genes that are silent.”
Previous research has shown that gene “reactivation” is indeed possible through several ways of stimulating mental activity, such as using toys, playing games and similar activities. They act by stimulating other connected neuronal circuits. This could explain why intensive activities of this kind with children can show some positive results in those affected with autism.
This highly inheritable, developmental brain disorder alters basic behaviors needed for social interaction and includes a wide variety of symptoms that persist throughout life. Although treatment can relieve some of these symptoms, no treatment has yet been found that can fully resolve the disease’s most serious disabilities.
The number of cases of autism has increased dramatically since the 1980s due in part to better diagnosis and perhaps due to more actual causative conditions. Why the numbers would be increasing in society today is a question that has not yet been resolved.
According to the U.S. Centers for Disease Control one in every 150 children has autism or autism-related disorders in the United States. Some states have experienced huge increases in the number of cases of this disorder.
There may also be an alternative approach to dealing with this disorder. Perhaps, in addition to finding those elements that could turn the gene switch “on,” research should concentrate on finding those elements that result in the autism genes switching “off” in the first place.
Several environmental factors have been suggested as contributing to or exacerbating autism and its effects. These factors could be critical in future research; they include infectious diseases, certain foods, a maternal history of alcohol abuse, drug use, smoking, and some of the preservatives used in vaccines, among others.
Perhaps, if some of these act by switching the autism genes “off,” eliminating them from the child’s environment could reduce the punishing effects of the disease.
Whatever the cause(s) prove to be, these recent findings are encouraging and suggest that the day is closer when we may talk about this disease as merely part of the sad history of mental illness.
Cesar Chelala, M.D. and Ph.D., is an international public health consultant, who has conducted molecular genetics research at The Public Health Research Institute of the City of New York.