Michaela Hýblová, Jaroslav Budiš, František Ďuriš, Rastislav Hekel, Dagmar Landlová, Peter Križan, Alica Valachová, Miriam Vojvodová, Jana Kršiaková, František Cisárik, Iveta Mlkvá, Nadežda Mišovicová, Eleonóra Čmelová, Gabriel Minárik, Tomáš Szemes
NIPT500 - Prospective study in utilisation of multinomial distribution algorithm for non-invasive prenatal screening
of the most frequent aneuploidy
The prospective validation study NIPT 500 was running in the period from July 2015 to December 2016. The aim
of the study was to evaluate sensitivity and specificity of non-invasive prenatal detection of aneuploidy for chromosomes
21, 18 and 13 using the multinomial distribution model analysing the results of whole-genome sequencing
with low coverage in the group of pregnant women with increased risk of incidence in mentioned trisomies.
In the frame of the evaluated period, 447 samples were examined from pregnant women, in 381 a successful telephonic
survey was performed, with a sufficient time interval, aimed at confirmation of analysis results using
the multinomial algorithm. According to the information from the survey, 13 pregnancies were not discontinued.
In 65 samples the telephonic survey was not successful. One result of the analysis was non-informative also after
repeated blood sampling from a pregnant woman. The total number of samples positive for trisomy testing was
20. The test was positive for trisomy of the chromosome 21 in 13, for trisomy 18 in 3 and trisomy 13 in 4 pregnant
women. One test result was false positive for trisomy 21. In one case we detected partial monosomy of the
chromosome 18, which was confirmed postnatally (Picture 1). Sensitivity for all trisomies reached 100%. Specificity
for T21 was 99.71%, for T18 and T13 100%. The method „Multinomial” in combination with whole-genome
sequencing in the investigated cohort reached comparable values of sensitivity and specificity as in the other published
studies focused on the evaluation of other calculation models used in NIPT.