Trisomy 9 confined to the placenta: Prenatal diagnosis and neonatal follow-up

Chorionic villus sampling (CVS), performed on a woman in the 23rd menstrual week because of bilateral fetal hydronephrosis and suspected intrauterine growth retardation (IUGR), documented trisomy 9 in all cells examined. Chromosomes of amniocytes and fetal blood lymphocytes were normal. The ongoing pregnancy was monitored closely, and at 37 weeks, a phenotypic normal male infant was delivered. Multiple placental biopsies showed 47,XY,+9, while a repeat chromosome analysis of the infant and biopsies from the amniotic membrane were normal (46,XY). This case further emphasizes the association between placental aneuploidy and IUGR. To our knowledge, nonmosaic trisomy 9 in CVS confined to the chorionic villi and later confirmed in the placenta has not been reported previously.