UNILATERAL RENAL HYPOPLASIA AND CONTRALATERAL RENAL AGENESIS - A NEW ASSOCIATION WITH 45,X 46,XY MOSAICISM/

The association of urinary anomalies with Turner's syndrome is well es tablished. This report describes an unusual antenatal presentation of this cytogenetic disorder and the first reported case of unilateral re nal hypoplasia and contralateral renal agenesis in a 45,X/46,XY fetus. The fetus presented with severe third trimester oligohydramnios and s ymmetrical intrauterine growth retardation at 29 weeks and 2 days' ges tation. Chorionic villus cultures revealed a 45,X karyotype. A phenoty pically male infant weighing 1833 g was delivered at 35 weeks and 2 da ys. Chromosomal analysis of the newborn showed a 45,X/46,XY mosaicism, and surgical exploration revealed absence of the left kidney and a hy poplastic right kidney. The infant died at 11 months of age from renal failure and peritonitis. This case demonstrates that monosomy X may b e encountered in fetuses with marked growth delay and oligohydramnios. The etiology of the oligohydramnios in this case was a fetal renal ma lformation net previously described in Turner's syndrome. Antenatal cy togenetic findings should be confirmed postnatally, with a search for mosaicism, when monosomy X is encountered.