Gene discovery could help understanding of intellectual disabilities
Reported December 18, 2009
TORONTO Researchers at the Centre for Addiction and Mental Health have identified a gene involved in some forms of intellectual disability.
Dr. John Vincent said the findings could provide more clues to understand, diagnose, prevent and treat intellectual disabilities.
“If we find the genes then that can give us a clue as to what biological process is faulty in those individuals and that in itself can give us a clue as to how normal development occurs,” Vincent, a CAMH scientist said.
He said a mutation in a gene called TRAPPC9 causes the production of a truncated version of a protein and results in faulty cell function.
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 disabilities, which account for up to 50 per cent of intellectual disabilities world-wide, Vincent said.
Because there are no highly recognizable physical differences associated with the non-syndromic intellectual disabilities, it is more difficult to establish the genetic mutations that may cause them, he said.
Vincent said researchers have long suspected an inherited factor and his team first identified the TRAPPC9 gene in a large family from Pakistan that had seven members with non-syndromic intellectual disabilities.
He said the best way to map these genes is to use large families where there are multiple affected individuals but also families from cultures where cousin-cousin marriages are common.
Vincent’s findings are published this month in the American Journal of Human Genetics and confirmed by two other research teams.
“I was excited when we were publishing the paper but when two other groups found the same thing it became even more exciting,” Vincent said.
Intellectual disabilities, also known as developmental delay or mental retardation, are a group of disorders defined by diminished cognitive and adaptive development.
Affecting more males than females, they are diagnosed in between one and three per cent of the population.
Source : Canwest News Service