5.9 Mb microdeletion in chromosome band 17q22-q23.2 associated with tracheo-esophageal fistula and conductive hearing loss.
Only eight cases involving deletions of chromosome 17 in the region q22-q24 have been reported previously. We describe an additional case, a 7-year-old boy with profound mental retardation, severe microcephaly, facial dysmorphism, symphalangism, contractures of large joints, hyperopia, strabismus, bilateral conductive hearing loss, genital abnormality, psoriasis vulgaris and tracheo-esophageal fistula. Analysis with whole-genome SNP genotyping assay detected a 5.9 Mb deletion in chromosome band 17q22-q23.2 with breakpoints between 48,200,000-48,300,000 bp and 54,200,000-54,300,000 bp (according to NCBI 36). The aberration was confirmed by real-time quantitative PCR analysis. Haploinsufficiency of NOG gene has been implicated in the development of conductive hearing loss, skeletal anomalies including symphalangism, contractures of joints, and hyperopia in our patient and may also contribute to the development of tracheo-esophageal fistula and/or esophageal atresia.