A functional genetic link between distinct developmental language disorders.

Area of Science:

• Genetics
• Neuroscience
• Developmental Biology

Background:

• Rare mutations in the FOXP2 transcription factor gene are known to cause monogenic speech and language disorders.
• This study investigates the hypothesis that neural pathways regulated by FOXP2 contribute to more common language phenotypes, such as specific language impairment (SLI).

Purpose of the Study:

• To identify downstream targets of FOXP2 involved in language.
• To investigate the association between the FOXP2 pathway and specific language impairment.

Main Methods:

• Chromatin immunoprecipitation was used to identify genomic regions bound by FOXP2.
• Single-nucleotide polymorphisms (SNPs) within a candidate gene, CNTNAP2, were tested for association with language deficits in 184 families affected by SLI.

Main Results:

• FOXP2 was found to bind and down-regulate CNTNAP2, a gene encoding a neurexin expressed in the developing human cortex.
• Significant associations were detected between CNTNAP2 polymorphisms and nonsense-word repetition, a key marker of SLI (peak association P=5.0x10(-5) at rs17236239).
• The identified region showed overlap with genetic associations for language delays in autism spectrum disorder.

Conclusions:

• The FOXP2-CNTNAP2 pathway establishes a mechanistic link between FOXP2 and CNTNAP2.
• This pathway connects clinically distinct syndromes characterized by disrupted language development, including SLI and potentially autism-related language delays.