New research links autism to genetic disorder

New research from the United States suggests that autism may be caused by a genetic disorder.

A study by scientists at the University of Chicago Medical Center has found a rare chromosome abnormality on chromosome 16 appears to increase the risk of autism by 100 times.

Dr. Mark Daly of Massachusetts General Hospital who led the study says though the difference appeared in just 0.6 percent of subjects studied, it is the second most common recurrent genomic disorder associated with autism.

Autism includes a range of disorders, from mild Asperger's syndrome to profound mental retardation and an inability to socialise and affects as many as 1 in 150 children in the United States and up to 1.5 million children and adults.

The cause remains a mystery and is the subject of much controversy and speculation.

The study by Daly and colleagues of the Autism Consortium in Boston found deletions or duplications in chromosome 16 among 24 out of 2,252 people from families with autism problems in the United States and Iceland, compared to 2 out of 18,000 people chosen randomly.

The researchers say most of the mutations did not appear to have been inherited.

The researchers say though the abnormality does not mean that a child will definitely be autistic, it does substantially raise the risk and provides further evidence that the causes of autism are largely genetic.

The researchers suspect that the lost or damaged genes may also be involved in other cognitive, language and social impairments but believe that being able to identify the genetic defect could be another way to screen early for the disease.

Early intervention such as behavioral and educational therapy can have a positive impact on children who develop autism and other forms of developmental delay, and the researchers say any tool that can help give an earlier diagnosis at ages well before the formal diagnostic criteria apply can be very useful.

The study is published in the New England Journal of Medicine.