Deletion involving the TWIST locus and the HOXA cluster: a contiguous gene syndrome on 7p?

Deletion of TWIST on 7p21 leads to Saethre-Chotzen syndrome, whereas deletion of the HOXA cluster on 7p15.2 leads to hand-foot-genital syndrome. We report here a patient with 46,XY,del(7)(p15.2p21) who had craniosynostosis, maxillary hypoplasia, prominent ear crus, rectoperineal fistula, and hypoplastic fifth fingers. Using fluorescence in situ hybridization, we demonstrated the deletion to encompass the TWIST locus and the HOXA cluster. We suggest that many, if not all, of the features of this patient could be accounted for by combined haploinsufficiency of the TWIST and HOXA cluster. Hence, the patient's phenotype may define a new contiguous gene syndrome on 7p.