Gene mutation behind nonsyndromic mental retardation

Montreal, February 5: A non-inherited gene mutation contributes to nonsyndromic mental retardation (NSMR). This discovery by Canadian researchers is of vital importance, as NSMR is the most common form of mental retardation among children.

The lead researcher, Dr. Jacques L. Michaud of the Center of Excellence in Neuromics at the University of Montreal in Canada, with his colleagues, carefully observed SYNGAP1 gene in 94 patients. This gene produces a protein which is responsible for learning and memory in developing children.

On proceeding with their investigation, in three patients researchers found gene mutation, which was not there in the DNA samples of the parents of the patients, hence proving that mutation was not inherited.

Michaud said that the mutation could contribute to mental retardation as it involves those areas of the brain which affect the development, function and connection between neurons.

However, the gene mutation did not appear to occur in any other form of mental disorder.

The researchers studied 142 people with autism, 143 people with schizophrenia and 190 healthy people. None of these people had gene mutation.

This unique association between NSMR and SYNGAP1 gene mutation can be a benchmark in developing treatment methods for this highly common form of mental disorder.

“Nonsyndromic mental retardation is a very common problem -- it involves about 3 percent of the population,” said Dr. Michaud.

Dr. Randi Hagerman, a professor of pediatrics and medical director of the M.I.N.D. Institute at the University of California, believes that these findings can lead to better diagnosis of this problem.

“This suggests that more screening for this mutation should be done in the workup of patients,” said Dr. Hagerman.