A Novel Targeted Approach for Noninvasive Detection of Paternally Inherited Mutations in Maternal Plasma

The challenge in noninvasive prenatal diagnosis for monogenic disorders lies in the detection of low levels of fetal variants in the excess of maternal cell-free plasma DNA. Next-generation sequencing, which is the main method used for noninvasive prenatal testing and diagnosis, can overcome this challenge. However, this method may not be accessible to all genetic laboratories. Moreover, shotgun next-generation sequencing as, for instance, currently applied for noninvasive fetal trisomy screening may not be suitable for the detection of inherited mutations. We have developed a sensitive, mutation-specific, and fast alternative for next-generation sequencing-mediated noninvasive prenatal diagnosis using a PCR-based method. For this proof-of-principle study, noninvasive fetal paternally inherited mutation detection was performed using cell-free DNA from maternal plasma. Preferential amplification of the paternally inherited allele was accomplished through a personalized approach using a blocking probe against maternal sequences in a high-resolution melting curve analysis-based assay. Enhanced detection of the fetal paternally inherited mutation was obtained for both an autosomal dominant and a recessive monogenic disorder by blocking the amplification of maternal sequences in maternal plasma.