Parental origin of chromosome 4p deletion in Wolf-Hirschhorn syndrome.

We report on molecular studies in 7 patients with Wolf-Hirschhorn syndrome (WHC) not showing an obvious chromosome 4p deletion. Analysis of a set of polymorphic probes mapping in the 4p16.3 region showed the absence of paternal haplotypes in 5 cases, and maternal haplotypes in 2. These observations corroborate evidence for preferential paternal origin of the de novo 4p chromosome deletion. The overall results of molecular studies suggest that the preponderance of paternally derived WHC could be due, rather than to imprinting of this region, to an excess of structural rearrangements in the male meiosis, related to differences between the mechanisms of sperm and egg production.