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
