‘Environment’ Poses a Knotty Challenge in Autism

NEW YORK -- Parents of children with autism often ask pediatricians like me about the cause of the condition, and parents-to-be often ask what they can do to reduce the risk. But although there is more research in this area than ever before, it sometimes feels as if it’s getting harder, not easier, to provide answers that do justice to the evidence and also offer practical guidance.

Recent research has taught us more about the complexity of the genetics of autism, but the evidence also has suggested an important role for environmental exposures. It has become a very complicated picture: Genes matter, but we usually can’t tell how. Environmental exposures matter, but we usually don’t know which.

Autism and Genetics

LOS ANGELES -- Autism is an environmental illness -- at least in some cases. Just as lead paint chips can cause learning disabilities and radon in the basement can cause lung cancer, certain chemicals and other outside influences seem to help set autism in motion.

But autism is also a genetic disease. It definitely runs in families, and scientists have identified several specific genes that put kids at risk.

Scientists are trying to understand this complicated push and pull that molds a growing brain. A new study of twins published in the Archives of General Psychiatry makes a case that the disease is about 60% environmental and 40% genetic. Other experts quickly disputed the finding, claiming that genes are the biggest driver of autism.

Study: Stronger Environment-Autism Link

Contrary to current thinking, environmental factors may play a larger role than shared genes in the development of autism, a new study in twins suggests.
A second study in the same journal finds that anti-depressants during pregnancy may be one important environmental trigger.
In the first study, researchers from Stanford University identified 192 pairs of twins from a statewide California registry of children who receive services for developmental disabilities.