Non-Invasive Fetal Sex Determination Using SRY Specific Primers and Sybrgreen Real Time PCR
Presence of fetal cells and circulating free fetal DNA and RNA in maternal circulation represents the basic concept in developement of non-invasive prenatal diagnostic methods based on molecular biology and genetics. We introduced new methods for free fetal DNA isolation and detection in maternal circulation via DNA isolation from maternal plasma using real-time PCR SYBRGreen targeting and newly designed primers focused in SRY sequence. We determined gender in 46 singleton pregnancies, 22 boys and 24 girls and assessed the analytical and clinical validity. We reached 95.45% sensitivity and 95.83% specificity. We suggest improvements in molecular-biological procedures in the discussion, which could be used in studies of clinical utility of non-invasive prenatal diagnosis (NIPD) in decreasing amount of invasive procedures unnecessarily performed.
Tabor, A., Vestergaard CH., Lidegaard O. Fetal loss rate after chorionic villus sampling and amniocentesis: an 11 year national registry study. Ultrasound obstet gynecol 2009, 34: 12-13.
Lo YMD., Zhang J., Leung TN., Lau TK., Chang AMZ., Hjelm NM. Rapid clearance of fetal DNA from maternal plasma. Am J Hum Genet 1999, 64: 218-224.
Lo Y.M., Corbetta N., Chamberlain P.F. et al.: Presence of fetal DNA in maternal plasma and serum. Lancet 1997; 350: 485-487.
Avent ND., Chitty LS. Non - invasive diagnosis of fetal sex, utilisation of free fetal DNA in maternal plasma and ultrasound. Prenat Diagn 2006, 26: 598-603.
Lo Y.M., Tein M.S., Lau T.K., et al. Quantitative analysis of fetal DNA in maternal plasma and serum: implications for noninvasive prenatal diagnosis. Am. J. Hum. Genet. 1998; 62: 768-775.
Finnig K.M., Chitty L.S.: Non-invasive fetal sex determination: Impact on clinical practice. Seminars Fetal Noenatal Med 2008; 13: 69-75.
Lau T.W., Leung T.N., Chan L.Y., et al. Fetal clearance from maternal plasma is impaired in preeclampsia. Clin. Chem. 2002; 48: 2141-2146.
Hromadnikova I., Holubova B., Hridelova D. et al. Replicate real - time PCR testing of DNA in maternal plasma increases the sensitivity of non - invasive fetal sex determination. Prenat diagn 2003, 23: 235-238
Page-Christiaens GC, Bossers B, van der Schoot CE, de Haas M. Use of bi-allelic insertion/deletion polymorphisms as a positive control for fetal genotyping in maternal blood: first clinical experience. Ann N Y Acad Sci 2006. 1075: 123-129.
Hill M, Finning K, Mrtin P, Hogg J, Meaney C, Norbury G, Daniels G, Chitty LS. Non-invasive prenatal determination of fetal sex: translating research into clinical practice. Clin Genet 2010: 1-8.
Chan K.C., Ding C., Gerovasilli A, Yeung S.W., Chiu R., W.K., Leung T.N., Lau T.K., Chim S.S., Chung G.T., Nicolaides K.H., Lo Y.M.D. 2006. Hypermethylated RASSF1A in maternal plasma: a universal fetal DNA marker that improves the reliability of noninvasive prenatal diagnosis. Clin Chem. 52: 2211-2218
Chim S.S., Tong Y.K., Chiu R.W., Lau T.K., Leung T.N., Chan L.Y., Oudejans C.B., Ding C., Lo Y.M.D. 2005 Detection of the placental epigenetic signature of the maspin gene in maternal plasma. Proc. Natl. Acad. Sci. USA. 102(41): 14753-14758