Prenatal ultrasound detection of congenital cataract in trisomy 21.

A 45-year-old woman underwent serial ultrasound screening procedures during late first and second trimesters of pregnancy for advanced maternal age. Cultured amniocytes karyotype indicated full trisomy 21. Subsequently, the fetus developed congenital cataract diagnosed at 24 weeks. This is the first antenatal diagnosis of this complication of Down syndrome.