Inv dup del(4)(:p14 → p16.3::p16.3 → qter) with manifestations of partial duplication 4p and Wolf‐Hirschhorn syndrome

An 8‐year‐old girl with a combination of clinical manifestations of partial duplication 4p and the Wolf–Hirschhorn syndrome was studied. Chromosomal G‐banding and FISH analyses showed a 33.2‐Mb segment of inverted duplication at 4p14‐p16.3 and a 2.8‐Mb segment of deletion at 4p16.3‐pter (including the Wolf–Hirschhorn syndrome critical region). The chromosomes of the parents were normal. Her karyotype was thus 46,XX, inv dup del(4)(:p14 → p16.3::p16.3 → qter) de novo. The inverted duplication deletion was assumed to have arisen through chromatid breakage at 4p16.3, U‐type reunion at the breakpoints to produce a dicentric intermediate, breakage of the dicentric to result in a monocentric, and telomere capture/healing of the broken end. Olfactory receptor gene clusters at 4p16.3 were ruled out as an intermediary of the duplication deletion process. © 2003 Wiley‐Liss, Inc.