Trisomy 21 Syndrome – Challenges of Prenatal Diagnosis

Abstract

The trisomy 21 syndrome is one of the most common chromosomal diseases. Prenatal testing play an important role in diagnosing trisomy 21. Each stage of prenatal screening has its own limitations. This work demonstrates the challenges of diagnosis using first trimester screening, noninvasive prenatal test (NIPT), and invasive prenatal testing (IPT). The medical documentation of 29 children with diagnosed trisomy 21 was analyzed. First-trimester screening was conducted in 25 cases, with a high risk identified for 13 fetuses. NIPT was conducted in 10 cases, and high risk was identified in 9 cases. Ultrasound signs of fetal defects were detected in 24 cases. IPT was performed in 8 cases, and in three of them, trisomy 21 was not detected using the cytogenetic method on a chorionic villus sample. Thus, the most informative method was NIPT. Optimization of the use of laboratory methods and the timing of invasive diagnostics is required.