A rec(4) dup 4p inherited from a maternal inv(4)(p15q35): case report and review.

A rec(4) dup 4p inherited from a maternal inv(4)(p15q35) was detected in a four-year-old girl with malformations, developmental delay, and behavioral problems that resemble those for trisomy 4p. A review of eight other liveborns with rec(4) dup 4p shows that about 40% of them also have manifestations in common with trisomy 4p, but the rest have a variable spectrum of malformations. Overall, the rec(4) dup 4p phenotype is not specific, and a diagnosis would not have been feasible without cytogenetic studies. This lack of a clinically recognizable phenotype could reflect the effects of the variable sizes of deletions of 4q, molecular differences in the break points, or the known variable expression of trisomy 4p. The fact that 79% of the recombinants in the offspring of inv(4)(p13-p15q35) carriers are rec(4) dup 4p suggests that meiotic recombination favors its generation or that rec(4) dup 4q are more lethal in utero. Copyright 2002 Wiley-Liss, Inc.