FetalQuantSD: accurate quantification of fetal DNA fraction by shallow-depth sequencing of maternal plasma DNA

A technique developed by Chinese researchers will allow clinicians to accurately quantify the fetal DNA in a blood sample from the mother. The team, led by Peiyong Jiang of The Chinese University of Hong Kong, used genotype data derived from mothers' blood cells to filter high-throughput sequencing data from their plasma in order to identify non-maternal sequences which might come from the fetus. Some of these are sequencing errors, so the team developed a model to estimate how many of the non-maternal sequences are fetal DNA with a deviation from the true value rate of less than 1%. Determining the fraction of fetal DNA in maternal samples is important for accurately diagnosing genetic abnormalities during noninvasive prenatal testing. The technique requires very little sequence data, opening to the door to cheap and accurate quantification of fetal DNA fraction for noninvasive prenatal genetic tests.