Academics and Research / Magazine Feature

Researcher identifies potential ‘risk’ genes for dyslexia

The brain fascinates DU psychology Professor Bruce Pennington. Discovering what makes it work, and what doesn’t, is his life’s work. One such discovery landed Pennington’s work on the pages of Science magazine.

Pennington’s colleagues found that genetic miscues alter brain development in the womb, predisposing children to problems later in life. The discovery was selected as one of the top ten breakthroughs of the year in the Dec. 23, 2005 issue of Science magazine.

Pennington’s genetic research is part of a collaborative effort. He and a team of scientists from the University of Nebraska Medical Center, the Institute of Behavioral Genetics in Boulder, Colo., and Yale University have helped identify a gene, DCDC2, that causes dyslexia. This gene is also implicated in speech disorders and Attention Deficit Hyperactivity Disorder (ADHD). Scientists in Europe recently have identified three other genes that cause dyslexia. These genes affect the early wiring of the brain.

One of Pennington’s colleagues, Dr. Jeffrey Gruen, an associate professor of pediatrics at Yale University’s School of Medicine, says dyslexia is a hot-button issue for students who struggle with reading in school. It’s of great concern to their parents, teachers, principals and administrators yearning to understand its cause and what can be done to improve reading performance.

“Perhaps the single most important significance of these findings is to confirm the heritability studies pioneered by Professor Pennington and his colleagues,” says Gruen. “It shows that the majority of the variance in reading performance tasks—as much as 60 percent—is attributable to genetic factors.”

The findings linking specific genes to reading tasks, independent of IQ, means that even students who struggle with reading can be as smart as their fluent-reading peers. Pennington hopes that by identifying the genetic risk factors that can lead to disorders such as dyslexia, ADHD and autism, clinicians and educators can earlier identify patients at risk and provide preventative treatment.

Genetic discoveries are making news now, but Pennington has long been interested in the study of genetic influences on atypical development. In the 1970s, Pennington was invited to participate in a University of Colorado Health Sciences Center study linking genes to dyslexia.

“At the time we didn’t know much at all about genes,” says Pennington. “The fact that we’ve now narrowed the pool to four potential ‘risk’ genes for dyslexia is remarkable.”

As part of his long-running research, Pennington is looking at linkages between dyslexia and other speech and language disorders. He’s looking, too, at their distribution within families.

“We’ve been studying some families for nearly 30 years and we’ve gone back to test new generations of children,” Pennington says. “In a few families, we have documented four and five generations of individuals with dyslexia.”

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