Possible to detect causes of autism in over a third of cases

It may be possible to find the causes for autism in over a third of cases, suggests research in the Journal of Medical Genetics. And these are likely to include a range of factors.

Autism is a chronic and severe disorder that takes the form of severely impaired language and social skills, delayed development, and repetitive behaviours. Three times as many boys as girls are affected, and three quarters of those with autism will have a mental disability. It is thought that a combination of a genetic predisposition and a harmful external factor early in infancy could explain its development.

The research team studied 25 autistic adults with a mental disability to determine the reasons for their autism. All the adults were given a physical examination including eye and ear, nose and throat investigations, brain scans, screens for metabolic and blood abnormalities and full genetic analysis.

The researchers found definitive causes for autism in five of the adults, including fetal alcohol syndrome, neonatal disorders, disturbed cholesterol mechanism and genetic defects. Probable causes were found for another four, one of which included an external factor likely to have caused the damage, although the nature of this factor was not known.

The authors suggest that recent research suggests an increasing role for genetic factors in the development of autism, but large studies of families would need to be done for more conclusive evidence.