Genetics of language impairment

Vernes SC et al. A functional genetic link between distinct developmental language disorders. NEJM 359;22:2337-2345.2008

and editorial Strombsword K. The genetics of speech and language impairment NEJM 359; 22:2381-3 2008.

The editorial notes that virtually all cases of familial language disturbance have complex polygenic multifactorial transmission. In addition assessment methods vary. In 1990, a 3 generation British family had autosomal dominant transmission of oral motor and speech dyspraxia. They carried a mutuation of FOXP2 gene which encodes a transcription factor. That protein may also be associted with oral motor apraxia, low noverbal IQ and nonverbal learning disorders. Vernes et al. above reported that FOXp2 downregulates the expression of CNTNAP2, a gene that encodes a neurexin protein. Further, using nonsense word repetition, CNTNAP2 is associated with a specific language impairment. They also suggested a possible relationship with autism. However, results do have some problems which are reviewed.