BACKGROUND: Cell-free fetal DNA (cffDNA) constitutes approximately 10% of the cell-free DNA in maternal plasma and is a suitable source of fetal genetic material for @entity146 ( @entity146 ). The objective of this study was to determine the feasibility of using digital PCR for @entity146 in pregnancies at risk of @entity3458 . METHODS: Minor-groove binder (MGB) TaqMan probes were designed to discriminate between wild-type hemoglobin A and mutant (hemoglobin S) alleles encoded by the @entity5358 ( @entity5358 ) gene in cffDNA isolated from maternal plasma samples obtained from pregnancies at risk of @entity3458 . The fractional fetal DNA concentration was assessed in male-bearing pregnancies with a digital PCR assay for the Y chromosome-specific marker @entity16439 . In pregnancies with a female fetus, a panel of biallelic insertion/deletion polymorphism (indel) markers was developed for the quantification of the fetal DNA fraction. We used digital real-time PCR to analyze the dosage of the variant encoding hemoglobin S relative to that encoding wild-type hemoglobin A. RESULTS: The sickle cell genotype was correctly determined in 82% (37 of 45) of male fetuses and 75% (15 of 20) of female fetuses. Mutation status was determined correctly in 100% of the cases (25 samples) with fractional fetal DNA concentrations >7%. The panel of indels was informative in 65% of the female-bearing pregnancies. CONCLUSIONS: Digital PCR can be used to determine the genotype of fetuses at risk for @entity3458 . Optimization of the fractional fetal DNA concentration is essential. More-informative indel markers are needed for this assay's comprehensive use in cases of a female fetus.

Digital PCR analysis of maternal plasma for noninvasive detection of XXXX .

@entity16439 :: ('7258', 'Gene') :: ['DYS14'] @entity3458 :: ('MESH:D000755', 'Disease') :: ['sickle cell anemia'] @entity5358 :: ('3043', 'Gene') :: ['hemoglobin, beta', 'HBB'] @entity146 :: ('MESH:D001523', 'Disease') :: ['NIPD', 'noninvasive prenatal diagnosis']
@entity3458 :: (MESH:D000755,Disease) :: ['sickle cell anemia']
