A gene, called TRAPPC9, which is involved in some forms of intellectual disability has been identified by scientists at the Centre for Addiction and Mental Health (CAMH).
Two international research teams independently have confirmed the findings of Dr. John B. Vincent, a scientist at CAMH, and his team.
"This spotlights the intense interest that genetics is bringing to types of inherited intellectual disability that, to date, have been poorly understood," said Vincent.
"Now that we have identified TRAPPC9 as a gene that may be associated with hundreds of thousands of cases of intellectual disability world-wide, we can build on that knowledge with research to help individuals and their families," he added.
Unlike intellectual disabilities that are part of a syndrome with other medical conditions or physical abnormalities, TRAPPC9 is associated with non-syndromic types of intellectual disability-causing up to 50 per cent of intellectual disability worldwide.
"The discovery announced today sheds light on a gene for intellectual disability on one of the non-sex chromosomes, just the seventh such gene that we know of," said Vincent.
The mutation in the TRAPPC9 gene causes the production of a truncated version of a protein and results in faulty cell function.
The researchers first identified and mapped out the TRAPPC9 gene in a large family from Pakistan that had at least seven members with non-syndromic intellectual disability.
"To date, most such genes have only been found responsible for disease in a single family," he added.
But, the researchers also found a mutation in the same gene in a family from Iran, confirming the gene's importance.
"This additional finding gives us a very strong reason to continue to explore the gene and its possible mutations," said Vincent.
The study has been published in The American Journal of Human Genetics.