3Bussani C,Cioni R,Mattei A,et al.Prenatal diagnosis of commonaneuploidies in transcervical samples using quantitative fluorescent PCRanalysis[J].Mol Diagn Ther,2007,11(2):117-121.
4Garcia-Sagredo J M.Fifty years of cytogenetics:a parallel view of theevolution of cytogenetics and genotoxicology[J].Biochim Biophys Ac-ta,2008,1779(6/7):363-375.
5Reeves R H,Baxter L L,Richtsmeier J T.Too much of a good thing:mechanisms of gene action in Down syndrome[J].Trends Genet,2001,17(2):83-88.
6Lo Y M,Corbetta N,Chamberlain P F,et al.Presence of fetal DNAin maternal plasma and serum[J].Lancet,1997,350(9076):485-487.
7Lun F M,Chiu R W,Allen-Chan K C,et al.Microfluidics digitalPCR reveals a higher than expected fraction of fetal DNA in maternalplasma[J].Clin Chem,2008,54(10):1664-1672.
8Chiu R W,Akolekar R,Zheng Y W,et al.Non-invasive prenatal as-sessment of trisomy 21 by multiplexed maternal plasma DNA sequen-cing:large scale validity study[J].BMJ,2011,342:c7401.
9Nicolaides K H,Snijders R J,Gosden C M,et al.Ultrasonographi-cally detectable markers of fetal chromosomal abnormalities[J].Lan-cet,1992,340(8821):704-707.
10Sismani C,Kitsiou-Tzeli S,Ioannides M,et al.Cryptic genomic im-balances in patients with de novo or familial apparently balanced trans-locations and abnormal phenotype[J].Mol Cytogenet,2008,1:15.