The capillary electrophoresis ability to distinguish and analyse free foetal DNA in maternal plasma using STR loci
Background: Real-time PCR systems are mostly used to distinguish the foetal genotype in maternal plasma in pregnant women. In this case, the Y- chromosome specific probes from the male specific region (MSY) are used to distinguish male foetus. This work, supported by the grant agency IGA MZCR NR/7817-3, describes the possibilities in free foetal DNA detection and STR quantification on capillary electrophoresis.
Methods/Results: Artificial genotype mixtures ranging from 0,2 % to 100 % to simulate maternal and paternal genotypes and 65 DNA samples from pregnant women in different stage of pregnancy were used for DNA quantification and detection. Foetal genotype was confirmed by biological father genotyping. The detection was performed in STR from the 21st chromosome Down syndrome (DS) responsible region by innovated Refined Quantitative Fluorescent PCR which allows the revealing and quantification of even very rare DNA mosaics.
The STR quantification was assessed in artificial mixtures of genotypes and discriminability of particular genotypes was at the few percent level. Foetal DNA was detected in 60 % of thetested samples. The precise statistics will be displayed on the poster.
Conclusions: The RQF PCR application in quantification and differentiation between maternal and foetal genotypes by STR loci could be of importance in noninvasive prenatal diagnostics as another possible marker for DS risk assessment.