SEVERE FETAL MALFORMATIONS ASSOCIATED WITH TRISOMY-16 CONFINED TO THEPLACENTA

Chorionic villus sampling (CVS) and amniocentesis were performed on a pregnant woman during her 24th week of amenorrhoea following an ultras ound scan which showed a fetus with hydrocephaly, intrauterine growth retardation (IUGR), and a single umbilical artery. The direct karyotyp e from the cytotrophoblast was non-mosaic 47,XX,+16, while in amniotic fluid and several fetal tissues, studied post-mortem, a normal 46,XX karyotype was found in more than 400 cells. Uniparental disomy (UPD) w as excluded by molecular genetic studies. Autopsy confirmed the echogr aphic findings; in addition, agenesis of the corpus callosum and polys plenia were observed. This is the second example of congenital abnorma lity associated with confined placental mosaicism (CPM) for trisomy 16 , without evidence of either UPD or an apparent contribution of abnorm al cells to the fetus. (C) 1997 by John Wiley & Sons Ltd.