Prenatal diagnosis of nonmosaic trisomy 9 in a fetus with severe renal disease.

We report a case of nonmosaic trisomy 9 presenting at 21 weeks of gestation with polycystic, echogenic horseshoe kidney, collapsed bladder, absent amniotic fluid, and intrauterine growth restriction. Color Doppler imaging demonstrated no blood flow signals from renal vessels. Fetal blood sampling confirmed a 47,XX,+9 karyotype, with no evidence of mosaicism, and increased serum beta2-microglobulin levels of 10.7 mg/l, consistent with severe renal failure. A repeat scan at 23 weeks also revealed a dysmorphic face, bilateral microphthalmia, and a cerebellar vermian defect. Follow-up examinations showed progressive growth restriction leading to fetal death at 33 weeks of gestation. This report demonstrates that fetuses with nonmosaic trisomy 9 may present with severe renal abnormalities and confirms that cases seen in the second and third trimesters usually have a dismal outcome.