Ultrasound findings in prenatal diagnosis of trisomy 18 associated with elevated levels of maternal serum alpha-fetoprotein

Abstract

Rationale: Trisomy 18, also referred to as Edwards syndrome, is the second most common autosomal trisomy syndrome. Trisomy 18 can be identified during prenatal screening by the detection of abnormal maternal serum results and one or more structural abnormalities on ultrasound. Previous studies confirmed that levels of pregnancy-related plasma protein A, alpha-fetoprotein, and free β-subunit of human chorionic gonadotropin in the serum of pregnant women carrying fetuses with trisomy 18 were lower than those in women with normal pregnancies. Patient concerns: A 29-year-old pregnant woman with a high risk of trisomy 18 underwent maternal serum screening at 16 weeks of gestation. The patient exhibited an elevated level of maternal serum alpha-fetoprotein (125 U/mL; 3.5225-fold higher than the multiple of the median). Ultrasonography revealed multiple abnormalities. Diagnoses: Culture of amniotic fluid cells revealed a karyotype of 47, XY, +18. Interventions and outcomes: The pregnancy was terminated. Lessons: Trisomy 18 can be identified prenatally by detection of abnormal levels of key proteins in the maternal serum, and detection of one or more structural abnormalities by ultrasound screening. Prenatal serological screening combined with ultrasound can effectively diagnose fetuses with trisomy 18 in the second trimester.