Carrier screening has historically assessed a relatively small number of autosomal recessive and X-linked conditions selected based on frequency in a specific subpopulation and association with severe morbidity or mortality. Advances in genomic technologies enable simultaneous screening of individuals for several conditions. The American College of Medical Genetics and Genomics recently published a clinical practice resource that presents a framework when offering screening for autosomal recessive and X-linked conditions during pregnancy and preconception and recommends a tier-based approach when considering the number of conditions to screen for and their frequency within the US population in general. This laboratory technical standard aims to complement the practice resource and to put forth considerations for clinical laboratories and clinicians who offer preconception/prenatal carrier screening. <<<

Taila Hartley, Deborah Marshall, Meryl Acker, Katharine Fooks, Meredith K Gillespie, E Magda Price, Ian D Graham, Alexandre White-Brown, Layla MacKay, Stella K Macdonald, Lauren Brady, Angela Y Hui, Joseph D Andrews, Ashfia Chowdhury, Erika Wall, Élisabeth Soubry, Grace U Ediae, Samantha Rojas, Daniel Assamad, David Dyment, Mark Tarnopolsky, Sarah L Sawyer, Caitlin Chisholm, Gabrielle Lemire, Kimberly Amburgey, Joanna Lazier, Roberto Mendoza-Londono, James J Dowling, Tugce B Balci, Christine M Armour, Priya T Bhola, Gregory Costain, Lucie Dupuis, Melissa Carter, Lauren Badalato, Julie Richer, Christie Boswell-Patterson, Peter Kannu, Dawn Cordeiro, Jodi Warman-Chardon, Gail Graham, Victoria Mok Siu, Cheryl Cytrynbaum, Alison Rusnak, Ritu B Aul, Grace Yoon, Hernan Gonorazky, Vanda McNiven, Saadet Mercimek-Andrews, Andrea Guerin, Ashish R Deshwar, Ashish Marwaha, Rosanna Weksberg, Natalya Karp, Maggie Campbell, Sarah Al-Qattan, Andrew Y Shuen, Michal Inbar-Feigenberg, Ronald Cohn, Anna Szuto, Cara Inglese, Myriam Poirier, Lauren Chad, Beth Potter, Kym M Boycott, Robin Hayeems, Care4Rare Canada Consortium <<<

PURPOSE: To evaluate the diagnostic utility of publicly funded clinical exome sequencing (ES) for patients with suspected rare genetic diseases.METHODS: We prospectively enrolled 297 probands who met eligibility criteria and received ES across 5 sites in Ontario, Canada, and extracted data from medical records and clinician surveys. Using the Fryback and Thornbury Efficacy Framework, we assessed diagnostic accuracy by examining laboratory interpretation of results and assessed diagnostic thinking by examining the clinical interpretation of results and whether clinical-molecular diagnoses would have been achieved via alternative hypothetical molecular tests.RESULTS: Laboratories reported 105 molecular diagnoses and 165 uncertain results in known and novel genes. Of these, clinicians interpreted 102 of 105 (97%) molecular diagnoses and 6 of 165 (4%) uncertain results as clinical-molecular diagnoses. The 108 clinical-molecular diagnoses were in 104 families (35% diagnostic yield). Each eligibility criteria resulted in diagnostic yields of 30% to 40%, and higher yields were achieved when >2 eligibility criteria were met (up to 45%). Hypothetical tests would have identified 61% of clinical-molecular diagnoses.CONCLUSION: We demonstrate robustness in eligibility criteria and high clinical validity of laboratory results from ES testing. The importance of ES was highlighted by the potential 40% of patients that would have gone undiagnosed without this test. <<<

Kimberly Martin, Pe'er Dar, Cora MacPherson, Melissa Egbert, Zachary Demko, Sheetal Parmar, Katelyn Hashimoto, Sina Haeri, Fergal Malone, Ronald J Wapner, Ashley S Roman, Asma Khalil, Revital Faro, Rajeevi Madankumar, Noel Strong, Robert M Silver, Nidhi Vohra, Jon Hyett, Matt Rabinowitz, Charlly Kao, Hakon Hakonarson, Bo Jacobsson, Mary E Norton <<<

PURPOSE: The aim of this study was to assess the performance of cell-free DNA (cfDNA) screening to detect sex chromosome aneuploidies (SCAs) in an unselected obstetrical population with genetic confirmation.METHODS: This was a planned secondary analysis of the multicenter, prospective SNP-based Microdeletion and Aneuploidy RegisTry (SMART) study. Patients receiving cfDNA results for autosomal aneuploidies and who had confirmatory genetic results for the relevant sex chromosomal aneuploidies were included. Screening performance for SCAs, including monosomy X (MX) and the sex chromosome trisomies (SCT: 47,XXX; 47,XXY; 47,XYY) was determined. Fetal sex concordance between cfDNA and genetic screening was also evaluated in euploid pregnancies.RESULTS: A total of 17,538 cases met inclusion criteria. Performance of cfDNA for MX, SCTs, and fetal sex was determined in 17,297, 10,333, and 14,486 pregnancies, respectively. Sensitivity, specificity, and positive predictive value (PPV) of cfDNA were 83.3%, 99.9%, and 22.7% for MX and 70.4%, 99.9%, and 82.6%, respectively, for the combined SCTs. The accuracy of fetal sex prediction by cfDNA was 100%.CONCLUSION: Screening performance of cfDNA for SCAs is comparable to that reported in other studies. The PPV for the SCTs was similar to the autosomal trisomies, whereas the PPV for MX was substantially lower. No discordance in fetal sex was observed between cfDNA and postnatal genetic screening in euploid pregnancies. These data will assist interpretation and counseling for cfDNA results for sex chromosomes. <<<

Noura S Abul-Husn, Priya N Marathe, Nicole R Kelly, Katherine E Bonini, Monisha Sebastin, Jacqueline A Odgis, Avinash Abhyankar, Kaitlyn Brown, Miranda Di Biase, Katie M Gallagher, Saurav Guha, Nicolette Ioele, Volkan Okur, Michelle A Ramos, Jessica E Rodriguez, Atteeq U Rehman, Amanda Thomas-Wilson, Lisa Edelmann, Randi E Zinberg, George A Diaz, John M Greally, Vaidehi Jobanputra, Sabrina A Suckiel, Carol R Horowitz, Melissa P Wasserstein, Eimear E Kenny, Bruce D Gelb <<<

PURPOSE: Adoption of genome sequencing (GS) as a first-line test requires evaluation of its diagnostic yield. We evaluated the GS and targeted gene panel (TGP) testing in diverse pediatric patients (probands) with suspected genetic conditions.METHODS: Probands with neurologic, cardiac, or immunologic conditions were offered GS and TGP testing. Diagnostic yield was compared using a fully paired study design.RESULTS: A total of 645 probands (median age 9 years) underwent genetic testing, and 113 (17.5%) received a molecular diagnosis. Among 642 probands with both GS and TGP testing, GS yielded 106 (16.5%) and TGPs yielded 52 (8.1%) diagnoses (P < .001). Yield was greater for GS vs TGPs in Hispanic/Latino(a) (17.2% vs 9.5%, P < .001) and White/European American (19.8% vs 7.9%, P < .001) but not in Black/African American (11.5% vs 7.7%, P = .22) population groups by self-report. A higher rate of inconclusive results was seen in the Black/African American (63.8%) vs White/European American (47.6%; P = .01) population group. Most causal copy number variants (17 of 19) and mosaic variants (6 of 8) were detected only by GS.CONCLUSION: GS may yield up to twice as many diagnoses in pediatric patients compared with TGP testing but not yet across all population groups. <<<

Desheng Liang, David S Cram, Hu Tan, Siyuan Linpeng, Yingdi Liu, Huaiyu Sun, Yu Zhang, Feng Tian, Hongmin Zhu, Mengnan Xu, Hua Wang, Fuli Yu, Lingqian Wu <<<

PURPOSE: To assess the clinical performance of an expanded noninvasive prenatal screening (NIPS) test ("NIPS-Plus") for detection of both aneuploidy and genome-wide microdeletion/microduplication syndromes (MMS).METHODS: A total of 94,085 women with a singleton pregnancy were prospectively enrolled in the study. The cell-free plasma DNA was directly sequenced without intermediate amplification and fetal abnormalities identified using an improved copy-number variation (CNV) calling algorithm.RESULTS: A total of 1128 pregnancies (1.2%) were scored positive for clinically significant fetal chromosome abnormalities. This comprised 965 aneuploidies (1.026%) and 163 (0.174%) MMS. From follow-up tests, the positive predictive values (PPVs) for T21, T18, T13, rare trisomies, and sex chromosome aneuploidies were calculated as 95%, 82%, 46%, 29%, and 47%, respectively. For known MMS (n = 32), PPVs were 93% (DiGeorge), 68% (22q11.22 microduplication), 75% (Prader-Willi/Angleman), and 50% (Cri du Chat). For the remaining genome-wide MMS (n = 88), combined PPVs were 32% (CNVs ≥10 Mb) and 19% (CNVs <10 Mb).CONCLUSION: NIPS-Plus yielded high PPVs for common aneuploidies and DiGeorge syndrome, and moderate PPVs for other MMS. Our results present compelling evidence that NIPS-Plus can be used as a first-tier pregnancy screening method to improve detection rates of clinically significant fetal chromosome abnormalities. <<<

PURPOSE: This workgroup aimed to develop an evidence-based clinical practice guideline for the use of noninvasive prenatal screening (NIPS) for pregnant individuals at general risk for fetal trisomy 21, trisomy 18, or trisomy 13 and to evaluate the utility of NIPS for other chromosomal disorders.METHODS: The NIPS Evidence-Based Guideline Work Group (n = 7) relied on the results from the recent American College of Medical Genetics and Genomics (ACMG) systematic review to form the evidentiary basis of this guideline. Workgroup members used the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework to draft recommendations. The guideline underwent extensive internal and external peer review with a public comment period before approval by the ACMG Board of Directors.RESULTS: Evidence consistently demonstrated improved accuracy of NIPS compared with traditional screening methods for trisomies 21, 18, and 13 in singleton and twin gestations. Identification of rare autosomal trisomies and other microdeletion syndromes with NIPS is an emerging area of interest.CONCLUSION: ACMG strongly recommends NIPS over traditional screening methods for all pregnant patients with singleton and twin gestations for fetal trisomies 21, 18, and 13 and strongly recommends NIPS be offered to patients to screen for fetal sex chromosome aneuploidy. <<<

Genomic microarrays used to assess DNA copy number are now recommended as first-tier tests for the postnatal evaluation of individuals with intellectual disability, autism spectrum disorders, and/or multiple congenital anomalies. Application of this technology has resulted in the discovery of widespread copy number variation in the human genome, both polymorphic variation in healthy individuals and novel pathogenic copy number imbalances. To assist clinical laboratories in the evaluation of copy number variants and to promote consistency in interpretation and reporting of genomic microarray results, the American College of Medical Genetics has developed the following professional guidelines for the interpretation and reporting of copy number variation. These guidelines apply primarily to evaluation of constitutional copy number variants detected in the postnatal setting. <<<

Erin Rooney Riggs, Erica F Andersen, Athena M Cherry, Sibel Kantarci, Hutton Kearney, Ankita Patel, Gordana Raca, Deborah I Ritter, Sarah T South, Erik C Thorland, Daniel Pineda-Alvarez, Swaroop Aradhya, Christa Lese Martin <<<

PURPOSE: Copy-number analysis to detect disease-causing losses and gains across the genome is recommended for the evaluation of individuals with neurodevelopmental disorders and/or multiple congenital anomalies, as well as for fetuses with ultrasound abnormalities. In the decade that this analysis has been in widespread clinical use, tremendous strides have been made in understanding the effects of copy-number variants (CNVs) in both affected individuals and the general population. However, continued broad implementation of array and next-generation sequencing-based technologies will expand the types of CNVs encountered in the clinical setting, as well as our understanding of their impact on human health.METHODS: To assist clinical laboratories in the classification and reporting of CNVs, irrespective of the technology used to identify them, the American College of Medical Genetics and Genomics has developed the following professional standards in collaboration with the National Institutes of Health (NIH)-funded Clinical Genome Resource (ClinGen) project.RESULTS: This update introduces a quantitative, evidence-based scoring framework; encourages the implementation of the five-tier classification system widely used in sequence variant classification; and recommends "uncoupling" the evidence-based classification of a variant from its potential implications for a particular individual.CONCLUSION: These professional standards will guide the evaluation of constitutional CNVs and encourage consistency and transparency across clinical laboratories. <<<

Yajie Zhao, Eugene J Gardner, Marcus A Tuke, Huairen Zhang, Maik Pietzner, Mine Koprulu, Raina Y Jia, Katherine S Ruth, Andrew R Wood, Robin N Beaumont, Jessica Tyrrell, Samuel E Jones, Hana Lango Allen, Felix R Day, Claudia Langenberg, Timothy M Frayling, Michael N Weedon, John R B Perry, Ken K Ong, Anna Murray <<<

PURPOSE: The study aimed to systematically ascertain male sex chromosome abnormalities, 47,XXY (Klinefelter syndrome [KS]) and 47,XYY, and characterize their risks of adverse health outcomes.METHODS: We analyzed genotyping array or exome sequence data in 207,067 men of European ancestry aged 40 to 70 years from the UK Biobank and related these to extensive routine health record data.RESULTS: Only 49 of 213 (23%) of men whom we identified with KS and only 1 of 143 (0.7%) with 47,XYY had a diagnosis of abnormal karyotype on their medical records or self-report. We observed expected associations for KS with reproductive dysfunction (late puberty: risk ratio [RR] = 2.7; childlessness: RR = 4.2; testosterone concentration: RR = -3.8 nmol/L, all P < 2 × 10-8), whereas XYY men appeared to have normal reproductive function. Despite this difference, we identified several higher disease risks shared across both KS and 47,XYY, including type 2 diabetes (RR = 3.0 and 2.6, respectively), venous thrombosis (RR = 6.4 and 7.4, respectively), pulmonary embolism (RR = 3.3 and 3.7, respectively), and chronic obstructive pulmonary disease (RR = 4.4 and 4.6, respectively) (all P < 7 × 10-6).CONCLUSION: KS and 47,XYY were mostly unrecognized but conferred substantially higher risks for metabolic, vascular, and respiratory diseases, which were only partially explained by higher levels of body mass index, deprivation, and smoking. <<<

PURPOSE: The study aimed to determine the diagnostic yield, optimal timing, and methodology of next generation sequencing data reanalysis in suspected Mendelian disorders.METHODS: We conducted a systematic review and meta-analysis of studies that conducted data reanalysis in patients with suspected Mendelian disorders. Random effects model was used to pool the estimated outcome with subgroup analysis stratified by timing, sequencing methodology, sample size, segregation, use of research validation, and artificial intelligence (AI) variant curation tools.RESULTS: A search of PubMed, Embase, Scopus, and Web of Science between 2007 and 2021 yielded 9327 articles, of which 29 were selected. Significant heterogeneity was noted between studies. Reanalysis had an overall diagnostic yield of 0.10 (95% CI = 0.06-0.13). Literature updates accounted for most new diagnoses. Diagnostic yield was higher after 24 months, although this was not statistically significant. Increased diagnoses were obtained with research validation and data sharing. AI-based tools did not adversely affect reanalysis diagnostic rate.CONCLUSION: Next generation sequencing data reanalysis can improve diagnostic yield. Owing to the heterogeneity of the studies, the optimal time to reanalysis and the impact of AI-based tools could not be determined with confidence. We propose standardized guidelines for future studies to reduce heterogeneity and improve the quality of the conclusions. <<<