The Uptake of Partner Participation in Sequential Preconception Carrier Screening
Authors: Wagner Andrew , Duncan Jeffrey , Fiddler Morry , Shulman Lee 
Published: July 2024

Introduction: Carrier screening that is performed in the preconception period allows for couples at risk for having children affected with certain single gene (Mendelian) conditions to be identified. This is the most optimal timeframe to perform such screening. Most obstetric providers utilize a sequential process in which the patient first undergoes screening and their partner is only offered testing if the initial results reveal that the first is a carrier for one or more autosomal recessive (AR) deleterious variants. If the partner fails to undergo screening, the couple cannot obtain meaningful and actionable risk information for future or current pregnancies. In this study, we sought to assess the frequency of completed carrier screening risk assessment among individuals and couples who were undergoing preconception screening at two prenatal screening programs staffed by genetic counselors and geneticists. Materials and Methods: We reviewed the screening outcomes for individuals and couples who presented for preconception carrier screening from January 1, 2020 through December 30, 2021 at Insight Medical Genetics and the clinical genetics program at Northwestern Medicine. All individuals received pretest genetic counseling prior to screening and posttest counseling after results were available. We evaluated individuals who were found to be a carrier of at least one deleterious variant and whether the partner of that person underwent carrier screening, and, if so, which type of screening. Results: 548 patients who identified as women underwent preconception carrier screening during the study period, along with 3 men presenting for initial screening. These screens consisted of a panel containing primarily autosomal recessive conditions with a few X-linked conditions. 247 individuals (45.1%) were positive for at least one pathogenic variant; of these, 244 (98.8%) were variants in genes associated with autosomal recessive conditions. A total of 219 partners (88.7%) underwent carrier screening, including the 3 female partners of the men who initiated carrier screening. Of note, 4 of the patients who underwent carrier screening reported not having a partner at the time of screening; accordingly, the partners who underwent screening represent 89.8% of individuals eligible for partner screening following an initial positive result. Of the 219 partners who underwent carrier screening, 201 (91.8%) chose a carrier screening panel of 150+ conditions, while 18 chose a more limited panel that included the gene(s) of relevance based on their partner’s results, with or without additional genes relevant to their learned/self-identified ethnicity or race. Conclusions: Approximately 10% of couples presenting for preconception genetic counseling and carrier screening found to be at potential risk for a child with an autosomal recessive condition did not obtain the requisite information to fully assess their risk of having an affected child. It is possible that the frequency of couples who do not obtain complete and actionable screening information is even higher when carrier screening is provided without the assistance of certified genetic counselors or geneticists. Recently, cell free DNA-based maternal screening has been introduced that assesses the risk for a limited number of genetic conditions in the fetus that may not require assessment of the partner. Nonetheless, providers must communicate to their patients that meaningful risk information can only be obtained when the partner undergoes screening in cases where the initial member of the couple is found to be a carrier of at least one autosomal recessive condition. Laboratories and professional societies need to develop effective educational outreach to patients and providers alike to improve the screening process for couples who want to determine if they are at risk to have a child with an inherited condition.