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Deciphering the spectrum and founder disease-causing variants (DCVs) in specific populations can shape and facilitate the diagnostic process of Lynch Syndrome (LS). The aim of this report was to comprehensively update on the genetic landscape of LS in the ethnically diverse Israeli-Jewish population. The cohort included 1080 carriers from 588 families; some from underrepresented, understudied Israeli ethnic groups recruited from 8 genetic institutes and high-risk clinics throughout the country. Variant classification was performed according to the American College of Medical Genetics criteria. A total of 157 DCVs were identified, 12 are reported here for the first time, and 9 reclassified. MSH2 DCVs were identified in 286 families (49%). Most DCVs (125/157, 80%) were noted in one or two families only. Sixteen DCVs, each detected in ≥ 5 families, and accounted for LS in 378/588 (64%) families. Constitutional mismatch repair deficiency (CMMRD) was diagnosed in 7 families. Twenty-five carriers (2.3%) had an additional DCV or risk alleles in another cancer susceptibility gene. In conclusion, MMR gene variant distribution in Israel is diverse. MSH2 is most commonly mutated due to founder DCVs. Though the 16 prevalent LS-associated DCVs were frequently detected in our cohort, none of them is frequently reported in the general population. These data should facilitate variant interpretation, spouse and cascade testing., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Surveillance of high-risk individuals for pancreatic ductal adenocarcinoma (PDAC) is recommended. This study aimed to determine the prevalence and outcomes of PDAC and its precursor lesions in BRCA1/2 pathogenic variants (PVs) carriers undergoing pancreatic surveillance., Methods: A retrospective multicenter cohort study of pancreatic surveillance outcomes in Israeli BRCA1/2 carriers preferably with a family history of PDAC., Results: A total of 180 asymptomatic carriers participated in the screening programs, including 57 (31.7%) with BRCA1 PVs, 121 (67.2%) with BRCA2 PVs, and 12 (6.6%) with PVs in BRCA1/2 and other genes, for a median follow-up period of 4 years. Ninety-one individuals (50.5%) fulfilled the International Cancer of the Pancreas Screening (CAPS) criteria for surveillance whereas 116 (64.4%) fulfilled the American College of Gastroenterology (ACG) criteria. There were four cases of adenocarcinoma and four cases of grade 1-neuroendocrine tumor (G1-NET). All were BRCA2 carriers, and two had no family history of PDAC. Three cancer patients were at resectable stages (IA, IIA, IIB) whereas one had a stage IIIB tumor. Of the G1-NET cases, one had surgery and the others were only followed. Success rate for detection of confined pancreatic carcinoma was thus 1.6% (three of 180) in the whole cohort, 1.6% (two of 116) among individuals who fulfilled ACG criteria and 2.2% (two of 91) in those fulfilling CAPS criteria for surveillance., Conclusions: Despite the low detection rate of PDAC and its' high-risk neoplastic precursor lesions among BRCA1/2 carriers undergoing pancreatic surveillance, 75% of cancer cases were detected at a resectable stage., (© 2023 American Cancer Society.)

Purpose: BRCA1/2 founder pathogenic variants (PVs) occur in various populations, but data on the mutational spectrum in Africans are limited. We examined BRCA1/2 PVs in breast cancer patients of Ethiopian Jewish (EJ) origin., Methods: We retrospectively analyzed BRCA1/2 test results and clinical features of EJ breast cancer patients from seven medical institutions. We obtained heterozygote carrier rates in affected individuals from the laboratories of the largest Israeli HMO (Clalit). Population carrier frequency was determined in EJ controls., Results: We identified three recurrent BRCA2 PVs in 11 EJ breast cancer patients (9 females, 2 males): c.7579delG, c.5159C > A, and c.9693delA. Only c.5159C > A was previously reported in Africans. In women, mean age at diagnosis was 35.7y; 8/9 were diagnosed with advanced disease. All tumors were invasive, 4/9 were triple negative. Only 3/11 carriers had relevant family history. Carrier rate in high-risk breast cancer patients was 11% (3/28; 95%CI [2.3%, 28.2%]). Combined carrier rate among controls was 1.8% (5/280; 95%CI [0.6%, 4.1%])., Conclusion: EJs harbor 3 recurrent BRCA2 PVs presenting with relatively severe breast cancer morbidity. Combined with the high BRCA2 carrier rate in the EJ population, these findings merit increasing awareness in this community and suggest that a culturally adapted population screening approach may be warranted., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Lynch syndrome is an inherited cancer predisposition syndrome caused by germline defects in any of the mismatch repair (MMR) genes. Diagnosis of carriers makes precision prevention, early detection, and tailored treatment possible. Herein we report a novel founder deletion of 18,758 bp, mediated by Alu repeats on both sides, detected in Ethiopian Jews. The deletion, which encompasses exon 9-10 of the MSH2 coding sequence, is associated mainly with early-onset MSH2/MSH6-deficient colorectal cancer (CRC) and liposarcoma. Testing of 35 members of 5 seemingly unrelated families of Ethiopian origin yielded 10/21 (48%) carriers, of whom 9 had CRC. Age at first tumor diagnosis ranged from 16 to 89 years. Carriers from the oldest generations were diagnosed after age 45 years (mean 57), and carriers from the younger generation were diagnosed before age 45 years (mean 30). Awareness of this founder deletion is important to improve patient diagnosis, institute surveillance from an early age, and refer patients for genetic counseling addressing the risk of bi-allelic constitutional MMR deficiency syndrome., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Carriers of pathogenic variants (PVs) in moderate-high-penetrance cancer susceptibility genes are offered tailored surveillance schemes for early cancer diagnosis. The clinical implications of low-penetrance variant carriers are less clear., Methods: Clinical and demographic data were retrieved for a cohort of Israeli individuals who underwent oncogenetic testing by the 30-gene cancer panel at Color Genomics laboratory, between 04/2013 and 12/2018., Results: Of 758 genotyped individuals, 504 had been diagnosed with cancer prior to testing: 283 (56%) had breast cancer and 106 (21%) colorectal cancer. Pathogenic or likely pathogenic (P/LP) variants were detected in 123 (16%) individuals. Overall, 44 different P/LP variants were detected in 18/30 cancer susceptibility genes; 20 of them were founder/recurrent mutations. Of the carriers, 39 (32%), 10 (8%), and 74 (60%) carried high-, moderate-, or low-penetrance variants, respectively. After excluding low-penetrance variants, 7% (33/504) of all cancer patients, 6% of breast or ovarian cancer patients were found to be carriers, as well as 7% (14/203) of individuals with colonic polyps, and 4% (11/254) of cancer-free individuals., Conclusions: The diagnostic yield of moderate- and high-penetrance PVs using multigene panel testing was 6%, with 3.7% carriers of non-recurrent PVs. This yield should be discussed during pre-test counseling, and emphasizes the need for harmonized recommendations regarding clinical implications of low-penetrance variants.