From Blood Test to Genome Sequencing: The Professional Guide to Genetic Tests in Pregnancy

Prof. Yuval Yaron presents a professional guide to genetic tests in pregnancy, distinguishing between screening tests (NIPT, nuchal translucency) and diagnostic tests (CVS, amniocentesis). The article reviews the genetic chip, exome sequencing, and emphasizes the importance of genetic counseling in making informed decisions.

Prof. Yuval Yaron, an expert in medical genetics and director of the Prenatal Genetic Diagnosis Unit at Ichilov, presents a professional guide to genetic tests in pregnancy. The article distinguishes between screening tests, which calculate probability (nuchal translucency, biochemical screening, NIPT), and diagnostic tests based on direct sampling of fetal cells (CVS, amniocentesis). It explains that NIPT is highly sensitive for trisomy 21 but does not replace diagnostic testing due to the possibility of false-positive results from placental mosaicism. The genetic chip (CMA) identifies quantitative changes at high resolution and has replaced karyotyping in most cases. Exome sequencing is intended for cases of abnormal structural findings with a normal chip, and is usually performed in a trio format including the parents. The article addresses the challenge of variants of uncertain significance (VUS) and emphasizes the importance of genetic counseling before and after testing. The information is presented as general enrichment and is not a substitute for personal medical advice.