Two cases of 16q12.1q21 deletions and refinement of the critical region.

Interstitial deletions of 16q chromosome including 16q12.1q21 region are very rare, with only three cases reported to date. Main clinical features include dysmorphisms, short stature, microcephaly, eye abnormalities, epilepsy, development delay, intellectual disability, and autism spectrum disorder. We report two independent subjects with 16q12.1q21 deletion syndrome presenting with dysmorphic facial features, developmental delay, strabismus, and aggressive behavior. A minimal region of overlap spanning 1.7 Mb on chromosome 16, including IRX5, GNAO1, and NUDT21 genes was shared among these two cases and those previously reported. This minimal region of overlap suggests the potential pathogenic role of these genes, previously implicated in diseases of the central nervous system.