TY - CHAP M1 - Book, Section TI - Prenatal Testing, Noninvasive Screening, Invasive Testing, and Carrier Screening A1 - Savage, Melissa A1 - Hanson, Karen A1 - Wapner, Ronald A1 - Faucett, W. Andrew A2 - Murray, Michael F. A2 - Babyatsky, Mark W. A2 - Giovanni, Monica A. A2 - Alkuraya, Fowzan S. A2 - Stewart, Douglas R. Y1 - 2014 N1 - T2 - Clinical Genomics: Practical Applications in Adult Patient Care AB - Summary:Pregnancies found to be at greater than population (high) risk for a genetic disorder are offered invasive diagnostic testing by chorionic villus sampling (CVS) or amniocentesis. These diagnostic tests have a small risk of inducing a pregnancy loss but will diagnose a specific genetic disorder with greater than 99% accuracy.Karyotype, FISH, or microarray are testing options for diagnosis of fetal genetic disorders on chorionic villus or amniotic fluid specimens.Ancestry and family history are tools used to determine which pregnancies are at risk for specific genetic disorders and should help guide carrier screening.The carrier state of some Mendelian disorders is frequent enough in the general population that offering screening to all pregnant couples and those presenting preconception is recommended.Screening tests can be used during pregnancy, at as early as 10 weeks, to identify pregnancies at increased risk for common fetal trisomies such as those causing Down syndrome and Edwards syndrome (trisomy 21 and 18).Uses:Invasive testing—CVS and amniocentesisProvide a definitive diagnosis for pregnancies identified as having an increased risk of a genetic disorder.Invasive testing is most commonly performed on women who are at an increased risk for a chromosome abnormality based on age-related risk, abnormal noninvasive screening results, and/or abnormal ultrasound findings.Invasive testing is offered for disease-specific testing when the parent(s) are confirmed carrier(s), affected with a dominant genetic disorder, or known to carry a balanced translocation.American College of Obstetrics and Gynecology, Guidelines, 2007All women, regardless of age, should have the option of invasive testing.Maternal age of 35 years alone should no longer be used as a cutoff to determine who is offered screening versus who is offered invasive testing. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accessmedicine.mhmedical.com/content.aspx?aid=1102703614 ER -