Study: Mental retardation linked with gene mutation

LOS ANGELES, Feb. 5 (Chinese media) -- A genetic mutation may contribute to nonsyndromic mental retardation, the most common form of mental retardation suffered by children, a new study has found.

What's unusual about the mutation is that it occurs during development of the child and is not passed on by the child's parents, according to the study results published in the February issue of the New England Journal of Medicine.

In the study, researchers at the University of Montreal in Canada examined the SYNGAP1 gene -- which produces a protein critical for learning and memory -- in 94 patients with nonsyndromic mental retardation. The researchers identified mutations in the gene in three children.

These are new mutations which are found in the kids, but not intheir parents, and the mutation arises in the development of the kids, according to the findings.

The mutations involve the brain, especially those areas that affect the development, function and connection between neurons, said the study.

The researchers then looked for the same mutations in 142 people with autism, 143 people with schizophrenia and 190 healthy people. None of these people had the mutations associated with nonsyndromic mental retardation, the study said.

One important aspect of this finding is that it explains the origins of nonsyndromic mental retardation, said lead researcher Dr. Jacques L. Michaud. "For a lot of families, not having an explanation makes it difficult to accept the condition. Having an explanation helps them to better accept the condition," he said.

Children and adults who have nonsyndromic mental retardation have no physical abnormality. They look like any other child or adult, but they nonetheless have the condition, Michaud said.