Single Nucleotide Polymorphism-Based Analysis of Cell-Free Fetal DNA in 3000 Cases from Germany and Austria.
Data from 3 008 patients, who underwent single-nucleotide-polymorphism (SNP)-based noninvasive prenatal testing (NIPT) are presented.


METHODS
The PanoramaTM test (Natera, San Carlos, CA) was used to analyze cell-free fetal DNA from maternal blood for trisomies 21, 18, and 13, triploidy and sex-chromosome aneuploidies.


RESULTS
In 2 942 (97.8%) cases, a result was obtained. The average fetal fraction was 10.2%. A high-risk result for fetal aneuploidy was made for 65 (2.2%) cases. In 59 (90.8%) of these cases, invasive testing confirmed the aneuploidy. There were 6 false-positive cases. In the false-positive group, the fetal fraction was significantly lower. The overall positive predictive value was 90.8%. No false-negative cases were reported but many patients in this study have not delivered yet. Therefore, exact data cannot be given for potential false-negative cases.


CONCLUSIONS
SNP-based NIPT is a reliable screening method for evaluating the risk of aneuploidies of chromosomes 21, 18 and 13. By using NIPT, the number of invasive procedures may be reduced significantly compared to maternal age and first-trimester screening.
Institut für Klinische Genetik Nordrhein, Essen, Germany.
B
B
Eiben
amedes Hamburg, Zentrum für Endokrinologie, Kinderwunsch und Pränatale Medizin, Hamburg, Germany.
M
M
Krapp
Genetic Department, amedes Institut f. Labormedizin und Klinische Genetik Institut f. Labormedizin und Klinische Genetik Rhein/ Ruhr MVZ GmbH, Essen, Germany.
H
H
Borth
Genetic Department, amedes Institut f. Labormedizin und Klinische Genetik Rhein/ Ruhr MVZ GmbH, Essen, Germany.
N
N
Kutur
MVZ FCH, amedes Hamburg, Zentrum für Pränatale Medizin, Hamburg, Germany.
P
P
Kreiselmaier
amedes Labor, Human Genetics, Hannover, Germany.
R
R
Glaubitz
UFK Wien, Dep. for Prenatal Diagnostic and Therapy, Wien, Austria.
J
J
Deutinger
KH Nordwest, Obstetrics & Gynecology, Frankfurt/Main, Germany.
E
E
Merz
chromosomal aberration; down syndrome; laboratory tests; pregnancy; screening
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