Molecular cytogenetic and clinical characterization of a patient with a 5.6-Mb deletion in 7p15 including HOXA cluster.

Here, we describe the clinical features of a boy with a 5.6-Mb deletion at chromosome 7p15.1-p15.3. He has mild facial anomalies, hand-foot abnormalities, hypospadias, congenital heart defects, and supernumerary nipples. This deletion was detected by array comparative genomic hybridization and verified by fluorescence in situ hybridization using BACs selected from the USCS genome browser. This deletion was not found in subsequent FISH analysis of the parental chromosomes. The deleted region contains several genes, including contiguous developmental genes on the HOXA cluster, which play a role in regulating aspects of morphogenesis during normal embryonic development. The patient's limb and urogenital features were similar to those observed in hand-foot-genital syndrome, which is caused by haploinsufficiency of HOXA13, whereas the congenital heart defect may reflect the deletion of HOXA3. We hypothesized that many clinical features of the patient were due to combined haploinsufficiency of the HOXA cluster. Our study also demonstrates the clinical usefulness of a molecular cytogenetic tool that is capable of detecting imbalances in the genome.