Detection of short tandem repeats at 5 loci and amelogenin with cell-free fetal DNA as a specimen in the development of prenatal paternity diagnostic tests

Introduction: A prenatal paternity test is one widely-used method of determining the paternity of an unborn child. Such tests using chorionic villus or amniocentesis may increase the risk of harm to both mother and foetus. In the present day, a prenatal paternity test using circulating cell-free fetal Deoxyribonucleic Acid (DNA) is one alternative method due to it being non-invasive and safe for both mother and foetus. Aim: The aim of this study is to detect Short Tandem Repeat (STR) at 5 Loci (vWA, TH01, D13S317, D18S51, and D21S11) and amelogenin genes in circulating cell-free fetal DNA in paternity tests. Materials and methods: Forty-one samples of maternal blood were obtained from pregnant woman. Circulating free fetal DNA was subsequently extracted. A paternity test was conducted using an STR test at loci vWA, TH01, D13S317, D18S51, D21S11 in circulating free fetal DNA. An analysis of the paternity test between loci > 200 bp and < 200 bp was also conducted to establish the sensitivity of the test. Results: There was a significant difference between maternal blood DNA and circulating cell-free fetal DNA (p = 0.000 D13S317; p = 0.000 D21S11; p = 0.000 D18S51; p = 0.000 vWA; p = 0.000 TH01; and p = 0.000 amelogenin genes). The locus < 200 bp also had a higher sensitivity than locus > 200 bp. Conclusion: Circulating free fetal DNA can be used as an alternative sample for prenatal paternity tests because of its similarity with maternal DNA.