Expanded carrier screening for reproductive risk assessment: An evidence-based practice guideline from the National Society of Genetic Counselors

Abstract

Expanded carrier screening (ECS) intends to broadly screen healthy individuals to determine their reproductive chance for autosomal recessive (AR) and X-linked (XL) conditions with infantile or early-childhood onset, which may impact reproductive management (Committee Opinion 690, Obstetrics and Gynecology, 2017, 129, e35). Compared to ethnicity-based screening, which requires accurate knowledge of ancestry for optimal test selection and appropriate risk assessment, ECS panels consist of tens to hundreds of AR and XL conditions that may be individually rare in various ancestries but offer a comprehensive approach to inherited disease screening. As such, the term "equitable carrier screening" may be preferable. This practice guideline provides evidence-based recommendations for ECS using the GRADE Evidence to Decision framework (Guyatt et al., BMJ, 2008, 336, 995; Guyatt et al., BMJ, 2008, 336, 924). We used evidence from a recent systematic evidence review (Ramdaney et al., Genetics in Medicine, 2022, 20, 374) and compiled data from peer-reviewed literature, scientific meetings, and clinical experience. We defined and prioritized the outcomes of informed consent, change in reproductive plans, yield in identification of at-risk carrier pairs/pregnancies, perceived barriers to ECS, amount of provider time spent, healthcare costs, frequency of severely/profoundly affected offspring, incidental findings, uncertain findings, patient satisfaction, and provider attitudes. Despite the recognized barriers to implementation and change in management strategies, this analysis supported implementation of ECS for these outcomes. Based upon the current level of evidence, we recommend ECS be made available for all individuals considering reproduction and all pregnant reproductive pairs, as ECS presents an ethnicity-based carrier screening alternative which does not rely on race-based medicine. The final decision to pursue carrier screening should be directed by shared decision-making, which takes into account specific features of patients as well as their preferences and values. As a periconceptional reproductive risk assessment tool, ECS is superior compared to ethnicity-based carrier screening in that it both identifies more carriers of AR and XL conditions as well as eliminates a single race-based medical practice. ECS should be offered to all who are currently pregnant, considering pregnancy, or might otherwise biologically contribute to pregnancy. Barriers to the broad implementation of and access to ECS should be identified and addressed so that test performance for carrier screening will not depend on social constructs such as race.

Keywords: carrier testing; health equity; population screening; preconception; risk assessment.