December 1, 2008

The Genetics Behind Language Impairment

New research suggests different types of language disorders may be genetically linked.

Variations of a gene called FOXP2 have been shown in previous research to cause a rare speech and language disorder, and mutations that affect the gene are associated with difficulties in learning and speaking. A new study shows a gene targeted by FOXP2 is associated with language impairment caused by several different disorders.

Researchers evaluated the speaking ability of families with a certain type of language impairment called specific language impairment. Those with autism or any other condition that affects speech were excluded from the study. The researchers then examined genes targeted by FOXP2 in the participants.

They found a gene called CNTNAP2 was directly affected by FOXP2 and can be associated with deficits in common types of language impairment. The findings give scientists hope they will soon better understand the genetics behind language disorders.

"Further analyses of the relevant regulatory networks -- including the FOXP2-CNTNAP2 pathway identified here -- may lead to a better understanding of neurogenetic mechanisms involved in typical language disorder," study authors wrote.

Results of the study also reveal certain variations in CNTNAP2 are associated with difficulty speaking in both language disorders and autism. Previous research has shown variations in the gene to be involved in Tourette's syndrome and a condition called focal epilepsy, which can cause autistic characteristics.

SOURCE: New England Journal of Medicine, 2008;359:2337-2345


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