2 research outputs found
Uncertainty of fetal fraction determination in Non-Invasive Prenatal Screening by highly polymorphic SNPs
Fetal fraction and the chromosome representation are the two key quantities used in Non-
Invasive Prenatal Screening (NIPS) to determine the aneuploidy status of a fetus. Several
methods for fetal fraction determination have been proposed in the literature, including a class
of the methods, denoted snpFF, based on high-coverage targeted sequencing of highly
polymorphic Single Nucleotide Polymorphisms (SNPs). The variant of snpFF, investigated here,
has similar properties as the other variants of snpFF. We point out that the variability of the
individual informative SNPs-based estimates of fetal fraction increases with the increase of fetal
fraction. At 4% fetal fraction the Inter-Quartile Range (IQR) of the individual estimates of fetal
fraction is around 3% and it increases to 6% at 15% fetal fraction. snpFF cannot detect fetal
fraction below 2.5% because the number of informative SNPs becomes too small, even zero