Research pinpoints gene as key in dyslexia

October 29, 2005|By LOS ANGELES TIMES

Researchers have identified a single gene alteration that might be a significant cause of dyslexia, a disorder that impairs the ability to read and comprehend written words.

Dr. Jeffrey R. Gruen, an associate professor of pediatrics at the Yale University School of Medicine, said an analysis of DNA from 153 families showed that a gene known as DCDC2 could be responsible for up to 20 percent of dyslexia cases.

Researchers have associated DCDC2 with dyslexia since 1994, but Gruen said his research is the first to assign it such a key role.

Using neural imaging, Gruen's team found that a mutated version of the gene - with a large deleted sequence - disrupted the way the dyslexics' brains sent and received impulses from the retina to the visual cortex.

Speaking yesterday at a meeting of the American Society of Human Genetics in Salt Lake City, Gruen said he altered the corresponding gene in rats and was able to disrupt the formation of the same brain circuits that impair reading ability in humans.

Some dyslexia researchers questioned Gruen's conclusion that a single gene could play such a prominent role in a condition as complex as dyslexia, which afflicts as many as 10 percent of U.S. children.

Gruen acknowledged that many other genes are involved in dyslexia, but he said his statistical analysis shows strong evidence of DCDC2's central role.

Gruen said the finding could lead to genetic testing that would allow earlier diagnoses of dyslexia, which can be ameliorated through phonics training.

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