Familial Cancer最新文献

Some 50% of Finnish Lynch Syndrome (LS) cases are caused by a founder variant in MLH1, in which the entire exon 16 has been lost due to an Alu-mediated recombination event. We piloted detecting the variant in FinnGen, a large genotyped cohort comprising approximately 10% of the current Finnish population, and validated the MLH1 founder variant status of identified individuals residing in the Central Finland Biobank catchment area. A consensus sequence flanking the deletion was identified in whole genome sequences of six LS individuals with the founder variant. Genotype data of 212,196 individuals was queried for regional matches to the consensus sequence. Enrichment of cancer and age at cancer onset was compared between matching and non-matching individuals. Variant status was validated for a subset of the identified individuals using a polymerase chain reaction assay. Allelic matches in a chosen target region was detected in 348 individuals, with 89 having a cancer diagnosis (Bonferroni-adjusted p-value = 1), 20 a familial cancer history (p-adj. < .001), with mean age of onset of cancer being 53.6 years (p-adj. = .002). Eighteen of potential variant carriers had been sampled by the Central Finland Biobank, of which four (22%) were validated as true variant carriers. The workflow we have employed identifies MLH1 exon 16 deletion variant carriers from population-wide SNP genotyping data. An alternative design will be sought to limit false positive findings. Large genotyped cohorts provide a potential resource for identification and prevention of hereditary cancer.

Background: Birt-Hogg-Dubé (BHD) syndrome is a genetic condition caused by pathogenic variants in the FLCN gene resulting in benign skin lesions, spontaneous pneumothorax, and increased risk for a variety of renal tumors. Skin manifestations of BHD include trichodiscoma (TD) and fibrofolliculoma (FF), which may represent the same pathologic entity. These lesions can identify BHD patients, who upon positive genetic testing can be considered for life-long surveillance for renal neoplasms.

Objective: To characterize patients diagnosed with TD and FF including rates and outcomes of genetics referral.

Methods: Retrospective chart reviews of patients with confirmed or possible diagnosis of TD or FF at the University of Michigan from September 2002 through October 2020 to assess pathologic findings, personal and family history of BHD manifestations, referral for genetic evaluation, and genetic testing results.

Results: 64 patients had a pathologic diagnosis of TD or FF, 16 of whom (25%) were referred to cancer genetics. Fourteen patients completed genetic evaluation, 9 of whom were diagnosed with BHD (64%), with 6 unique pathogenic variants in FLCN.

Conclusion: Providers should consider referral for genetic evaluation for patients with biopsy-proven TD or FF, as early diagnosis of BHD provides the opportunity for early detection and treatment of other BHD-associated conditions.

Germline genetic sequencing is now at the forefront of cancer treatment and preventative medicine. Cascade genetic testing, or the testing of at-risk relatives, is extremely promising as it offers genetic testing and potentially life-saving risk-reduction strategies to a population exponentially enriched for the risk of carrying a cancer-associated pathogenic variant. However, many relatives do not complete cascade testing due to barriers that span individual, relationship, healthcare community, and societal/policy domains. We have reviewed the published research on cascade testing. Our aim is to evaluate barriers to cascade genetic testing for hereditary cancer syndromes and explore strategies to mitigate these barriers, with the goal of promoting increased uptake of cascade genetic testing.

In the 33 years since the first diagnostic cancer predisposition gene (CPG) tests in the Manchester Centre for Genomic Medicine, there has been substantial changes in the identification of index cases and cascade testing for at-risk family members. National guidelines in England and Wales are usually determined from the National Institute of healthcare Evidence and these have impacted on the thresholds for testing BRCA1/2 in Hereditary Breast Ovarian Cancer (HBOC) and in determining that all cases of colorectal and endometrial cancer should undergo screening for Lynch syndrome. Gaps for testing other CPGs relevant to HBOC have been filled by the UK Cancer Genetics Group and CanGene-CanVar project (web ref. https://www.cangene-canvaruk.org/ ). We present time trends (1990-2020) of identification of index cases with germline CPG variants and numbers of subsequent cascade tests, for BRCA1, BRCA2, and the Lynch genes (MLH1, MSH2, MSH6 and PMS2). For BRCA1/2 there was a definite increase in the proportion of index cases with ovarian cancer only and pre-symptomatic index tests both doubling from 16 to 32% and 3.2 to > 8% respectively. A mean of 1.73-1.74 additional family tests were generated for each BRCA1/2 index case within 2 years. Overall close to one positive cascade test was generated per index case resulting in > 1000 risk reducing surgery operations. In Lynch syndrome slightly more cascade tests were performed in the first two years potentially reflecting the increased actionability in males with 42.2% of pre-symptomatic tests in males compared to 25.8% in BRCA1/2 (p < 0.0001).

Lynch syndrome is an underdiagnosed genetic condition that increases lifetime colorectal, endometrial, and other cancer risk. Cascade testing in relatives is recommended to increase diagnoses and enable access to cancer prevention services, yet uptake is limited due to documented multi-level barriers. Individual barriers such as feelings of fear, guilt, and anxiety and limited knowledge about Lynch syndrome as well as interpersonal barriers including complex family dynamics and language barriers limit family communication about Lynch syndrome and prevent uptake of genetic screening for relatives. Organizational and environmental barriers including a shortage of genetics professionals, high costs, and fears of discrimination also reduce cascade testing. These multi-level barriers may disproportionately impact underserved populations in the United States, such as individuals with lower incomes, limited English-speaking proficiency, lower educational attainment, and inadequate access to health systems. Multi-level facilitators of cascade testing include interpersonal support from family members, peers, and healthcare providers, educational resources, and motivation to improve family health. Taken together, these barriers and facilitators demonstrate a need for interventions and strategies that address multi-level factors to increase cascade testing in families with Lynch syndrome and other hereditary cancer conditions. We provide an example of a cascade testing intervention that has been developed for use in individuals diagnosed with Lynch syndrome and discuss the variety of current approaches to addressing these multi-level barriers.

Inherited cardiovascular diseases cover the inherited cardiovascular disease familial hypercholesterolemia and inherited cardiac diseases, like inherited cardiomyopathies and inherited arrhythmia syndromes. Cascade genetic counseling and testing in inherited cardiovascular diseases have had three decades of academic attention. Inherited cardiovascular diseases affect around 1-2% of the population worldwide and cascade genetic counseling and testing are considered valuable since preventive measures and/or treatments are available. Cascade genetic counseling via a family-mediated approach leads to an uptake of genetic counseling and testing among at-risk relatives of around 40% one year after identification of the causal variant in the proband, with uptake remaining far from complete on the long-term. These findings align with uptake rates among relatives at-risk for other late onset medically actionable hereditary diseases, like hereditary cancer syndromes. Previous interventions to increase uptake have focused on optimizing the process of informing relatives through the proband and on contacting relatives directly. However, despite successful information dissemination to at-risk relatives, these approaches had little or no effect on uptake. The limited research into the barriers that impede at-risk relatives from seeking counseling has revealed knowledge, attitudinal, social and practical barriers but it remains unknown how these factors contribute to the decision-making process for seeking counseling in at-risk relatives. A significant effect on uptake of genetic testing has only been reached in the setting of familial hypercholesterolemia, where active information provision was accompanied by a reduction of health-system-related barriers. We propose that more research is needed on barriers -including health-system-related barriers- and how they hinder counseling and testing in at-risk relatives, so that uptake can be optimized by (adjusted) interventions.

Genomic sequencing has emerged as a powerful tool with significant implications for patients and their relatives, however, empirical evidence suggests that effective dissemination of risk information within families remains a challenge. Policy responses to address this issue vary across countries, with Belgium notably lacking specific regulations governing nondisclosure of genetic risk. In this study, we conducted semi-structured interviews with clinicians from Belgian clinical genetics centers to gain insight into their perspectives on policy approaches to the disclosure of genetic risk within families. Using real-world examples of legislation and court rulings from France, Australia, and the UK, we explored clinician viewpoints on the roles and responsibilities of both patients and clinicians in the family communication process. Clinicians expressed confusion regarding what was legally permissible regarding contacting at-risk relatives. While there was a consensus among participants that patients have a responsibility to inform their at-risk relatives, participants were hesitant to support the legal enforcement of this duty. Clinicians mostly recognized some responsibility to at-risk relatives, but the extent of this responsibility was a subject of division. Our findings highlight the need for a comprehensive policy that clarifies the roles and responsibilities of clinicians and patients to inform at-risk relatives. Furthermore, the study underscores the practical challenges clinicians face in supporting patients through the complex process of family communication, suggesting a need for additional resources and the exploration of alternative approaches to communication.

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder, caused by germline variants in the serine/threonine kinase 11 (STK11) gene. However, mosaic variants in STK11 gene have been rarely described. A 25-year-old woman diagnosed with PJS due to multiple hamartomatous polyps in the gastrointestinal tract was referred to our clinic. In the molecular diagnosis, the patient was evaluated using the STK11 gene sequence analysis and multiplex ligation-dependent probe amplification (MLPA) method, which suggested no pathogenic variant to account for the clinical picture. Given that the clinical findings of the patient were consistent with those of PJS, the raw data from next-generation sequencing (NGS) were re-examined for mosaicism which led to the detection of a novel mosaic c.920 + 1G > T variant in STK11 gene with a rate of 23% (1860x). Deep read-level NGS was performed on buccal mucosa and polyp samples to determine mosaicism levels in other tissues. Variant frequencies were 29% (710x) and 31% (1301x), respectively. Mosaicism should be considered in cases with clear clinical diagnostic criteria, such as PJS, where the pathogenic variant cannot be detected by sequence analysis and MLPA methods. Identification of mosaicism in these patients is very important as it can have an impact on patient follow-up and genetic counseling for relatives.