Prenatal detection of an interstitial deletion in 4p15 in a fetus with an increased nuchal skin fold measurement.

Objectives: The detection of an increased nuchal translucency (NT) or nuchal fold (NF) measurement is associated with an increased risk of common aneuploidies. Only rarely is it associated with other types of chromosome abnormalities. We report the prenatal finding of an increased NF in a fetus with an interstitial 4p deletion. Methods: Standard karyotype analysis was followed by FISH with research generated BAC probes to precisely map the 4p deletion. Results: The karyotype of the fetus was determined to be 46,XX,del(4)(p15.2p16.1) by G-banding analysis and was refined to 46,XX,del(4) (p15.1p15.32) after FISH analysis. The breakpoints were narrowed to 150 kb regions on each side. The deletion is approximately 14.5 Mb, containing approximately 47 genes. Conclusions: We report a case of an increased NF measurement associated with a 4p deletion. A literature review revealed a previous case of a 4p deletion in a fetus with an increased NT. Since chromosome deletions are rarely associated with an increased NT or NF, we believe it is significant that a 4p deletion has now been found in two unrelated cases. We mapped the deletion with BAC probes, generating a list of possible candidate genes involved in the pathogenesis of increased nuchal skin folds.