Cell-free DNA screening for fetal aneuploidy as a clinical service.
Non-invasive prenatal testing (NIPT) through the analysis of cell free (cf)DNA is revolutionizing prenatal screening for fetal aneuploidy. Current methods used in clinical practice include shotgun massively parallel sequencing (s-MPS); targeted (t-MPS); and an approach that takes advantage of single nucleotide polymorphism (SNP) differences between mother and fetus. Efficacy of cfDNA testing for the common autosomal trisomies far exceeds that of conventional screening. Depending on the methodology used, reasons for discordancy between cfDNA results and fetal karyotype can include true fetal mosaicism, confined placental mosaicism, presence of a maternal karyotype abnormality, insufficient counting due to low fetal fraction, and a vanishing twin. Among the possible cfDNA strategies a Primary test has the highest performance but is expensive, while a Contingent cfDNA test can achieve high performance at a relatively low cost. Practicalities to be considered in the provision of testing include pretest counseling about the scope and accuracy of the testing, the interpretation of results when there is a low fetal fraction and follow-up studies for positive test results. The role of first trimester nuchal translucency measurement and conventional biochemical testing needs to be reassessed in the context of the use of cfDNA.
Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA. Electronic address: hsc2121@columbia.edu.
Howard
H
Cuckle
Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
Peter
P
Benn
Northwestern Reproductive Genetics, Chicago, IL 60611, USA.
Eugene
E
Pergament
D000782:Aneuploidy; D015415:Biomarkers / Q000097:blood; D025063:Chromosome Disorders / Q000097:blood / Q000175:diagnosis* / Q000191:economics / Q000196:embryology; D003362:Cost-Benefit Analysis; D004247:DNA / Q000097:blood*; D005189:False Positive Reactions; D005260:Female; D005820:Genetic Testing / Q000191:economics / Q000639:trends; D017048:Health Care Costs; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000191:economics / Q000639:trends; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000009:adverse effects / Q000191:economics / Q000639:trends
D015415:Biomarkers; D004247:DNA
Discordant; Fetal fraction; Non-invasive prenatal testing; Practicality; Screening strategy; cfDNA