• Noninvasive and invasive techniques in the prenatal screening of Down syndrome: a review
  • Arezu Karimpur zahmatkesh,1,*
    1. Molecular Genetics Department, natural sciences college, University of Tabriz / Medical Genetics Department, medicine college Shahid Beheshti of Medical Sciences University


  • Introduction: Down syndrome is a chromosomal disorder that is attributed to the extra genetic material of chromosome 21. This is included a portion or total of this chromosome. Down syndrome is the most common cause of mild to moderate intellectual disability. As well, patients present characteristic facial features and growth problems. Different methods have been used in prenatal screening for Down syndrome (DS) which developed significantly over the recent years with the upgrading the serum screening in the first- and second trimester and the introduction of cell-free fetal DNA. In this review, we discuss the various methods of prenatal screening and diagnosis and their importance in down syndrome.
  • Methods: This review article has been written by gathering information from articles published in Pubmed about Down syndrome and prenatal screening methods.
  • Results: The focus of prenatal screening has been on the detection of trisomy 21 (Down syndrome) since the 1980s. Multiple markers are used for risk screening of DS including pregnancy-associated plasma protein (PAPP)-A, inhibin A, human chorionic gonadotrophin (hCG), the free-β subunit of hCG, unconjugated estriol (uE3), inhibin A and AFP, ultrasound nuchal translucency (NT) and more specialized studies with molecular methods, including non-invasive and invasive sampling, respectively, including NIPT and CVS, amniocentesis, etc. More studies on the sensitivity and specificity of these screening techniques, and knowing the optimal time to perform each of them will be beneficial for the effective use of these methods.
  • Conclusion: This review presents all currently accessible noninvasive and invasive techniques for the screening and diagnosis of Down syndrome. By introducing these methods and the probable alternatives, the health care providers will be able to provide their patients with all the information essential to make an informed decision about their medical management.
  • Keywords: Down syndrome, prenatal screening, Noninvasive, invasive