Prenatal examination on Hb Bart's hydrops fetalis syndrome with cffDNA from maternal plasma by high-throughput sequencing

Objective To perform the noninvasive genetic typing of α-thalassemia (--SEA) by deep sequencing of cell-free fetal DNA (cffDNA) in maternal plasma using high-throughput sequencing technology. Methods α-thalassemia genotyping was performed on cffDNA maternal plasma of 34 pregnant women was isolated from bloods.It was performed that a series of next generation sequencing operations based on Ion Proton platform, including cffDNA extraction, library construction and hybridization, template preparation and enrichment, and sequencing.Multivariate Bayesian probability model was used to evaluate the probability of Hb Bart's hydrops fetalis syndrome of fetus.Subsequently, fetal DNA was extracted from amniotic fluids of pregnant women.Gap-PCR was performed to genotype α-thalassemia, and the coincidence rate of cffDNA from maternal plasma was compared with that of the fetal DNA from amniotic fluids. Results The results of cffDNA genotyping in plasma of 34 pregnant women were compared with those of amniotic fluid DNA.Twenty-eight cases were consistent, 4 cases were inconsistent, and 2 cases were unknown because the pregnant women did not receive prenatal diagnosis.The ultimate coincidence rate was 87.5%. Conclusion The identification of Hb Bart's hydrops fetalis syndrome (--SEA/--SEA) is successful with a high level of coincidence rate through cffDNA in plasma of pregnant women.