High rates of "atypical" single nucleotide polymorphism-based noninvasive prenatal screening results among consanguineous Arab American patients: A single center retrospective study.

Noninvasive prenatal screening (NIPS), using placental cell-free DNA from a maternal blood sample, is currently the most sensitive and specific screening tool for detecting common fetal aneuploidies. The aim of this study was to compare the rates of "atypical" single nucleotide polymorphism (SNP)-based NIPS results and subsequent pregnancy outcomes between Arab American and non-Arab American patients. We conducted a retrospective cohort study of pregnant Arab and non-Arab American patients who had SNP-based NIPS performed between September 2018 and January 2021 at an urban health system in Michigan. The rate of "atypical" results and other perinatal outcomes were compared between groups using descriptive statistics. "Atypical" results due to multifetal gestations, either undisclosed or unknown at time of ordering, were excluded. Five thousand eight hundred and seventy-three patients underwent SNP-based NIPS: 771 (13.1%) were identified as Arab American, 5102 (86.9%) were non-Arab American, and 49 (0.8%) patients received "atypical" results. Arab patients represented only 13.1% of patients screened (771/5873) but had a significantly higher rate of "atypical" results than non-Arab American patients (17/771 [2.2%] vs. 32/5102 [0.6%]; p < 0.001). Of the 17 Arab patients with "atypical" results, 9 (52.9%) were in known consanguineous relationships. No major congenital anomalies or chromosomal aberrations were identified for any patients who had "atypical" results, and no significant differences in other perinatal outcomes were observed between Arab and non-Arab American patients. A better understanding of the association between consanguinity and "atypical" SNP-based NIPS results would aid in appropriate test selection and interpretation and may help physicians and genetic counselors provide better perinatal counseling and follow-up care for patients in consanguineous relationships.

Clinical genetic counseling and translation considerations for polygenic scores in personalized risk assessments: A Practice Resource from the National Society of Genetic Counselors.

Polygenic scores (PGS) are primed for use in personalized risk assessments for common, complex conditions and population health screening. Although there is growing evidence supporting the clinical validity of these scores in certain diseases, presently, there is no consensus on best practices for constructing PGS or demonstrated clinical utility in practice. Despite these evidence gaps, individuals can access their PGS information through commercial entities, research programs, and clinical programs. This prompts the immediate need for educational resources for clinicians encountering PGS information in clinical practice. This practice resource is intended to increase genetic counselors' and other healthcare providers' understanding and comfort with PGS used in personalized risk assessments. Drawing on best practices in clinical genomics, we discuss the unique considerations for polygenic-based (1) testing, (2) clinical genetic counseling, and (3) translation to population health services. This practice resource outlines the emerging uses of PGS, as well as the critical limitations of this technology that need to be addressed before wide-scale implementation.

Clinical outcomes of preimplantation genetic testing for hereditary cancer syndromes: A systematic review.

OBJECTIVE: To conduct a systematic review of the published literature on clinical outcomes following preimplantation genetic testing for monogenic disorders (PGT-M) for hereditary cancer syndromes (HCS). METHODS: Three electronic databases (PubMed, Cochrane, and EMBASE) were searched for publications related to PGT-M for HCS. When appropriate, weighted means were used to calculate clinical and live birth rates. RESULTS: We identified 22 publications that reported on clinical and/or psychosocial outcomes of PGT-M for HCS. The weighted mean clinical pregnancy rate (CPR) per embryo was 33.5% (11 studies, 95% CI: 29.1%, 38.2%), and the CPR per cycle with embryonic transfer was 40.1% (14 studies, 95% CI: 36.1%, 44.3%). The weighted mean live birth rate (LBR) per embryo was 28.9% (11 studies, 95% CI: 24.7%, 33.4%) and the LBR per cycle with embryonic transfer was 33.2% (13 studies, 95% CI: 29.2%, 37.4%). The limited literature regarding the psychosocial outcomes of PGT-M for HCS suggests reproductive decision-making is difficult and additional support may be desired. CONCLUSION: These findings suggest that CPR and LBR following PGT-M for HCS are comparable to other monogenic disorders. Heterogeneity across studies suggests the overall CPR and LBR found may not be applicable to all HCS indications and PGT-M methodologies.