Complex rearrangement of chromosomes 7q21.13-q22.1 confirms the ectrodactyly-deafness locus and suggests new candidate genes

Abstract

Complex chromosomal rearrangements with more than two breakpoints are rare. We report on a 5-year-old girl, evaluated because of psychomotor delay, ectrodactyly of right hand and feet, craniofacial dysmorphic features, cleft palate, deafness, and tetralogy of Fallot. A standard karyotype suggested a small intrachromosomal duplication of chromosome 7q. The chromosomal rearrangement was characterized by mBAND, which disclosed a reciprocal interstitial translocation t(7;8)(q21q22;q23q24). FISH analysis and array-CGH analysis showed a paracentric inversion of 7q and a microdeletion of 7q21.13. The parents had normal chromosomes. The deletion found in the present patient confirms that candidate region of ectrodactyly-deafness (OMIM 220600) maps to 7q21 and suggests new candidate genes for that disorder. This patient also had facial features reminiscent of tricho-rhino-phalangeal syndrome and one chromosome breakpoint involved band 8q24, a locus for this disorder. In addition, FOG1 gene maps to 8q23 and has been implicated in a subset of subjects with tretralogy of Fallot. We suggest that the aberration of 8q may have contributed to her facial and cardiac findings.