De novo deletion of chromosome 2q24.2 region in a mentally retarded boy with muscular hypotonia.

To date, more than 100 cases with a deletion of chromosome 2q have been identified, although studies reporting small interstitial deletions involving the 2q24.2-q24.3 region are still rare. Here, we have described the genotype and the phenotype of a boy with a 5.3 Mb de novo deletion in this region, identified by SNP array analysis. The selected region included 20 genes, of which 4 are prominently expressed in the brain. Their combined haplo-insufficiency could explain the main clinical features of this patient which included mental retardation, severe hypotonia, joint laxity and mild dysmorphic traits.