Further phenotype description, genotype characterization in patients with de novo interstitial deletion on...

Interstitial deletions of the distal part of chromosome 2p seem to be rarely identified or reported: to date, only nine distinct patients have been published. The last three patients were diagnosed with the use of more recent molecular karyotyping technology (SNP array). We report on the natural history of an 8-year-old boy with dysmorphic features, postnatal overgrowth, microcephaly, generalized hypotonia, and global developmental delay. The diagnosis was accomplished by SNP array investigation that led to the identification of a de novo 7.4 Mb deletion of 2p23.2-p24.1. The present patient also developed a nonsyndromic auditory neuropathy. Since the deletion encompassed the OTOF gene, this haploinsufficiency suggests second allele sequencing as a possible cause (DFNB9). We describe the phenotype of the patient and review reports in patients with del 2p23 subsequent to the advent of the genomic era. At the time of identification of "new" micro- deletion and -duplication syndromes, the present report adds to the description of phenotype in patients with del(2)p(23.2;24.1) and the 2p23.2 region in particular.