Autism genetic clues ‘uncovered’

Scientists have found that patients with autism spectrum disorders are more likely to have extra copies of some DNA sequences than other people.

Autism is a lifelong developmental disability which impairs sufferers’ social interactions, communication and imagination.

According to a new study from US researchers, the extra copies/mutations, known as copy number variations (CNV), affect different genes in each patient.

They argue that this indicates that autistic behaviour can result from many possible genetic defects.

Their findings are based on an analysis of CNV in 264 families consisting of those with a single autistic child (‘simplex’ families), some with more than one sibling affected (‘multiplex’ families) and control families with no autistic children.

Writing in the Science journal, they describe how CNV appear to primarily affect families “sporadically”, resulting in just one child having autism, and are less important in multiplex families.

CNV were found in ten per cent of patients from simplex families, two per cent of multiplex families and one per cent of the control families.

Although the scientists note that they do not yet know how the CNV contribute to autism, they argue that they do appear to play a primary role.

“Improved technologies for mutation detection? promise to improve our power to identify new mutations associated with disease,” the researchers conclude.