title: Recent advances in the analysis of fetal nucleic acids in maternal plasma.
abstract: OBJECTIVE
  Noninvasive prenatal diagnosis can be achieved by analyzing cell-free fetal DNA in maternal plasma. The fact that circulating fetal DNA represents only a minor fraction of the DNA that is present in maternal plasma has presented analytical challenges for a number of applications. In this review, we discuss such challenges and how they have been resolved by recent developments in the field.
  
  
  RESULTS
  Digital molecular counting methods, such as digital PCR and massively parallel sequencing, have enabled high quantitative precision for maternal plasma DNA analysis. Noninvasive prenatal analysis of monogenic disease mutations has been achieved by identifying small quantitative differences between the mutant and wild-type alleles in maternal plasma. By measuring the small increment in the fractional concentrations of DNA derived from potentially aneuploid chromosomes in maternal plasma, fetal chromosomal aneuploidies have been detected with high diagnostic accuracies.
  
  
  CONCLUSIONS
  Recently, advances in molecular technologies have enhanced the diagnostic applications of maternal plasma DNA analysis for noninvasive prenatal diagnosis. We foresee that this technology could play an increasingly important role in prenatal investigations.
authors.affiliation: Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, Hong Kong, China. nancytsui@cuhk.edu.hk
authors.forename: Nancy Bo Yin
authors.initials: NB
authors.lastname: Tsui
authors.forename: Yuk Ming Dennis
authors.initials: YM
authors.lastname: Lo
mesh_terms: D004247:DNA / Q000097:blood / Q000235:genetics; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005315:Fetal Diseases / Q000097:blood* / Q000235:genetics*; D006801:Humans; D008431:Maternal-Fetal Exchange; D009696:Nucleic Acids / Q000097:blood*; D011247:Pregnancy / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D009696:Nucleic Acids; D004247:DNA