Researcher discovers genetic link to language disorder

A gene that has been associated with dyslexia now has been linked to another persistent disability that first surfaces in childhood - Specific Language Impairment.

A recently published study led by Mabel Rice at the University of Kansas is the first to report that a variant in the gene KIAA0319 is a likely culprit in Specific Language Impairment. Children with Specific Language Impairment, which affects about 7 percent of 5- to 6-year-olds, have no other developmental disorders, hearing loss or brain injuries but are late to begin talking. When they do talk, they use simpler sentence structure and immature grammar. Some also develop reading problems.

The finding is important because it shows that genes can affect language development and that other problems - such as speech production disorders and reading delays - are, in all likelihood, related.

"We've come to realize that language really sets the platform for reading to emerge and to thrive," Rice said. "Without a solid language system, it's much harder to get reading going."

Rice and a team of researchers from across the globe studied 322 individuals, including children with Specific Language Impairment, their parents and other family members. Participants completed diagnostic tests to determine the presence of Specific Language Impairment behavioral traits. Their genetic code was then scanned to identify mutations that family members had in common.

They found that variations in KIAA0319 had a strong effect on Specific Language Impairment traits, dyslexia and speech sound disorders - problems that persist throughout adulthood.

"It's an exciting time because we're beginning to see discoveries that have been 10 years in the making," Rice said.

Rice said that scientists know that Specific Language Impairment runs in families so the identification of a specific gene will contribute to improved diagnosis and treatment of language, reading and speech disorders. She emphasized that families should know that although Specific Language Impairment traits can be inherited, early intervention can offset its impact on language development and reading.

Rice is the director of the Center for Biobehavioral Neurosicences in Communication Disorders and the Fred and Virgina Merrill Distinguished Professor of Advanced Studies. She is affiliated with the Life Span Institute at KU.

By Mary-Margaret Simpson