The FOXP2 gene is also active in animals such as mice, birds and primates that obviously don't have speech problems, Miranda said.
The authors of the new study, from the Wellcome Trust Centre for Human Genetics at the University of Oxford, screened this gene and found that one of the other genes it interacts with is called CNTNAP2. An analysis of CNTNAP2 function in 184 families with common language impairments found that children with certain forms of the gene had language deficits, notably nonsense-word repetition.
The findings seem to raise more questions than they answer, but hopefully they provide a gateway for further discoveries, experts said.
"A lot of times the clues to the basis of a disease come from very small groups," said Miranda. "You find one family that clues you into the process, but then you have to work through the process."
The American Speech-Language-Hearing Association has more on language development.
SOURCES: Karin Stromswold, M.D., Ph.D., professor, psychology and member, Center for Cognitive Science, Rutgers University, New Brunswick, N.J.; Rajesh Miranda, Ph.D., associate professor, neuroscience and experimental therapeutics, Texas A&M Health Science Center College of Medicine; Nov. 6, 2008, New England Journal of Medicine
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