Toronto, July 17 (IANS) With the help of a new sequencing technology, scientists have isolated a gene linked to mental retardation.

Mental retardation, also called intellectual disability, denotes certain limitations in mental functioning and in skills such as communicating, taking care of oneself, and social skills.

John Vincent, senior scientist at the Centre for Addiction and Mental Health (CAMH) and colleagues, identified defects on the gene MAN1B1, among five families having children with intellectual disability, reports the American Journal of Human Genetics.

The individuals affected had similar physical features, and all had delays in walking and speaking. Some learned to care for themselves, while others needed help in bathing and dressing. In addition, some had epilepsy or problems with overeating, according to a CAMH statement.

All were found to have two copies of a defective MAN1B1 gene, one inherited from each parent. There were different types of mutations on the same gene - yet the outcome, intellectual disability, was the same in different families - confirming that this gene was the cause of the disorder.

"This mutation was seen in five families, which is one of the most seen so far for genes causing this form of recessive intellectual disability," said Vincent, who last year made a breakthrough by identifying the PTCHD1 gene, responsible for autism.