Background

Hemolytic disease of the fetus and newborn and fetal/ neonatal alloimmune thrombocytopenia are caused by maternal antibodies against paternal inherited fetal alloantigens on red blood cells or platelets. Noninvasive fetal genotyping is required to determine whether the fetus is at risk. Next-generation sequencing (NGS) has shown to be a reliable method for the noninvasive determination of fetal blood groups for diagnostic purposes.kein

Methods

Cell-free DNA was isolated from plasma of pregnant women with different gestational age and proven irregular alloantibodies against red blood cell antigens or platelets. A primer panel was designed to target sequences flanking single-nucleotide polymorphisms (SNPs)/exonic regions of GYPA (MNS), GYPB (MNS), RHD, RHCE, BCAM (LU), KEL, ACKR1 (FY), SLC14A1 (JK), SLC4A1 (DI), AQP1 (CO), ITGB3 (HPA-1), ITGA2 (HPA-5), CD109 (HPA-15), SRY and autosomal SNPs for internal control. All samples were sequenced using next-generation sequencing.

Results

In all samples, sequencing of polymorphic regions coding for common blood group antigens, SRY, and of anonymous SNPs allowed quantification of the fractional fetal DNA concentration. Non-maternal sequences were correctly determined in all pregnancies with a fraction of cell free fetal DNA that reached the pre-defined cut-off value of 4 %. In some pregnancies, the fetal fraction was below 4% and thus follow-up testing was recommended. In most cases, typing results were verified by confirmatory typing after birth.

Conclusion

Next generation targeted sequencing is a sensitive and specific tool for non-invasive prenatal diagnosis of fetal blood groups.

Offenlegung Interessenkonflikt:

No conflict of interest.