X pentasomy in an intracytoplasmic sperm injection pregnancy detected by nuchal translucency testing.

Althoughmaternally derived X pentasomy following intracytoplasmic sperm injection (ICSI) is rare, prenatal detection of a case offers insight into etiology and diagnosis. A 29-year-old gravida 1 whose pregnancy resulted from ICSI was referred for ultrasound screening at 11 weeks' gestation. Nuchal translucency thickness was 3.2 mm, and the fetal nasal bone was absent. Subsequent evaluation revealed karyotype 49,XXXXX. DNA microsatellite analysis showed the extra X chromosomes were maternal in origin. Termination of pregnancy was performed at 15 weeks. Because of the increased risk of sex chromosomal abnormalities in ICSI pregnancies, patients should be counseled prior to fertilization and standard prenatal care should include nuchal translucency measurement and any other elements necessary for indicated pregnancies to obtain a diagnosis.