TRISOMY-2 - CONFINED PLACENTAL MOSAICISM IN A FETUS WITH INTRAUTERINEGROWTH-RETARDATION

In a pregnancy that was monitored due to increased risk for Down syndr ome in the triple test, a normal karyotype was found in amniocentesis. Follow-up by serial ultrasound examinations revealed intrauterine gro wth retardation (IUGR) at 20 weeks of gestation. The parents decided t o terminate the pregnancy and the karyotype of the placental fibroblas ts was 47,XX,+2. Analysis of polymorphic markers of chromosome 2 demon strated (a) that trisomy 2 was confined to the placenta (CPM), (b) tha t the trisomy 2 cell line was a result of a meiotic I error of paterna l origin, and (c) that the fetal tissues with a normal karyotype were biparental disomy 2. (C) 1997 by John Wiley & Sons, Ltd.