Prenatal diagnosis and genetic analysis of double trisomy 48,XXX,+18

Prenatal diagnosis of simultaneous occurrence of double trisomy involving c hromosomes 18 and X is extremely rare. We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a fetus with both trisomy 18 and trisomy X. A 26-year-old, para 1 woman was referred for genetic coun selling at 36 weeks' gestation with the sonographic findings of intrauterin e growth retardation (IUGR), polyhydramnios, ventricular septal defect, and an enlarged cisterna magna. Both cordocentesis and amniocentesis revealed a consistent karyotype of 48,XXX,+18. Quantitative fluorescent polymerase c hain reaction using polymorphic small tandem repeat markers specific for ch romosomes 18 and X rapidly determined that both aneuploidies arose as a res ult of non-disjunction in maternal meiosis II. Our case shows that two nond isjunction events can occur not only in the same parent, but also in the sa me cell division. Our case also shows that double trisomy, 48,XXX,+18, can demonstrate an enlarged cisterna magna, IUGR and polyhydramnios in prenatal ultrasound. Copyright (C) 2000 John Wiley & Sons, Ltd.