Wolf-Hirschhorn and Pitt-Rogers-Danks syndromes caused by overlapping 4p deletions

Wolf-Hirschhorn syndrome (WHS), a multiple congenital malformation syndrome, and Pitt-Rogers-Danks syndrome (PRDS), a rare condition with similar anomalies, were previously thought to be clinically distinct conditions. While WHS has long been associated with deletions near the terminus of 4p, several recent studies have shown PRDS is associated with deletions in 4p16.3. In this paper we evaluate three patients, two described as PRDS and one diagnosed as WHS. We demonstrate that the molecular defects associated with the two syndromes show a considerable amount of overlap. We conclude that both of these conditions result from the absence of similar, if not identical, genetic segments and propose that the clinical differences observed between these two syndromes are likely the result of allelic variation in the remaining homologue.