Premium
Evolution in screening for Down syndrome
Author(s) -
Ashoor Al Mahri Ghalia,
Nicolaides KH
Publication year - 2019
Publication title -
the obstetrician and gynaecologist
Language(s) - English
Resource type - Journals
eISSN - 1744-4667
pISSN - 1467-2561
DOI - 10.1111/tog.12534
Subject(s) - trisomy , cell free fetal dna , false positive rate , down syndrome , prenatal screening , prenatal diagnosis , obstetrics , aneuploidy , medicine , computational biology , fetus , biology , computer science , pregnancy , genetics , artificial intelligence , chromosome , gene
Key content This article describes how screening for fetal trisomy 21 has evolved from advanced maternal age, with a detection rate of 30% at a false positive rate (FPR) of 5%, to second trimester serum biochemistry, with a detection rate of 60–75% at an FPR of 5%, and then to the first trimester combination of fetal nuchal translucency and serum biochemistry, with a detection rate of 90% at an FPR of 5%. The introduction of cell‐free DNA analysis of maternal blood is outlined. This method has improved detection rate to 99% with a reduction in FPR to 0.1%. As this test is currently expensive, it may be difficult to offer it to all patients as a first‐line method of screening. A feasible approach to the introduction of the cell‐free DNA test is discussed, which is to offer it contingent on the results of first‐line screening with the combined test.Learning objectives To understand the different methods available for screening for fetal trisomy 21. To learn about the performance of different methods of screening. To be able to describe the new method of screening by cell‐free DNA testing. To understand the issues related to clinical implementation of cell‐free DNA testing.Ethical issues Should the cell‐free DNA test be offered solely based on health economic considerations or on individual patient interests? Should screening be carried out for conditions other than trisomy 21?