Mosaic 7q31 deletion involving FOXP2 gene associated with language impairment.

We report on a 10-year-old patient with childhood apraxia of speech (CAS) and mild dysmorphic features. Although multiple karyotypes were reported as normal, a bacterial artificial chromosome array comparative genomic hybridization revealed the presence of a de novo 14.8-Mb mosaic deletion of chromosome 7q31. The deleted region involved several genes, including FOXP2, which has been associated with CAS. Interestingly, the deletion reported here was observed in about 50% of cells, which is the first case of mosaicism in a 7q31 deletion. Despite the presence of the deletion in only 50% of cells, the phenotype of the patient was not milder than other published cases. To date, 6 cases with a deletion of 9.1-20 Mb involving the FOXP2 gene have been reported, suggesting a new contiguous gene deletion syndrome characterized mainly by CAS caused by haploinsufficiency of the genes encompassed in the 7q critical region. This report suggests that children found with a deletion involving the FOXP2 region should be evaluated for CAS and that analysis of the FOXP2 gene including array comparative genomic hybridization should be considered in selected patients with CAS. Mosaic deletions in this area may also be considered as causative of CAS.