ERN GENTURIS clinical practice guidelines for the diagnosis, surveillance and management of people with Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé syndrome (BHD syndrome) is an autosomal dominant multisystem disorder with variable expression due to pathogenic constitutional variants in the FLCN gene. Patients with BHD syndrome are predisposed to benign cutaneous fibrofolliculomas/trichodischomas, pulmonary cysts with an associated risk of spontaneous pneumothorax, and renal cell carcinoma. A requirement for updated International consensus recommendations for the diagnosis and management of BHD syndrome was identified. Based on a comprehensive literature review and expert consensus within the fields of respiratory medicine, urology, radiology, dermatology, clinical oncology and clinical genetics, updated recommendations for diagnosis, surveillance and management in BHD syndrome were developed. With the widespread availability of FLCN genetic testing, clinical scenarios in which a diagnosis should be considered and criteria for genetic testing were defined. Following a clinical and/or molecular diagnosis of BHD syndrome, a multidisciplinary approach to disease management is required. Regular renal cancer surveillance is recommended in adulthood and life-long, but the evidence base for additional tumour surveillance is limited and further research warranted. Recommendations for the treatment of cutaneous, pulmonary and renal manifestations are provided. Awareness of BHD syndrome needs to be raised and better knowledge of the clinical settings in which the diagnosis should be considered should enable earlier diagnosis. Further details, including areas for future research topics are available at: https://www.genturis.eu/l=eng/Guidelines-and-pathways/Clinical-practice-guidelines.html .

Does a proactive procedure lead to a higher uptake of predictive testing in families with a pathogenic BRCA1/BRCA2 variant? A family cancer clinic evaluation.

The uptake of genetic counseling and predictive genetic testing by family members at risk for hereditary tumor syndromes is generally below 50%. To address this issue, a new guideline was introduced in the Netherlands in 2019 that aims to improve the sharing of information within families. In addition to cascade screening supported by follow-up telephone calls with the proband, municipal records were accessed to allow the geneticist to contact at-risk family members directly. We evaluated this procedure in 32 families with a (likely) pathogenic germline BRCA1/BRCA2 variant diagnosed at our hospital between May 1, 2020, and July 31, 2021, comparing current uptake with outcomes achieved for 33 families diagnosed in 2014. Fifteen months after diagnostic testing of the proband, the uptake was 43% (120/277), comparable to the 44% (87/200) registered previously. Among a subgroup of women at 50% risk aged 25-75 years, 71% (47/66) were tested, comparable to an earlier uptake of 69% (59/86). Of the 34 at-risk relatives we contacted directly, 17 (50%) underwent predictive testing. In conclusion, we found no evidence that the new procedure leads to a substantially increased uptake. Future research should be primarily aimed at understanding intrafamilial communication barriers.

Update of penetrance estimates in Birt-Hogg-Dubé syndrome.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome is a rare genetic syndrome caused by pathogenic or likely pathogenic germline variants in the FLCN gene. Patients with BHD syndrome have an increased risk of fibrofolliculomas, pulmonary cysts, pneumothorax and renal cell carcinoma. There is debate regarding whether colonic polyps should be added to the criteria. Previous risk estimates have mostly been based on small clinical case series. METHODS: A comprehensive review was conducted to identify studies that had recruited families carrying pathogenic or likely pathogenic variants in FLCN. Pedigree data were requested from these studies and pooled. Segregation analysis was used to estimate the cumulative risk of each manifestation for carriers of FLCN pathogenic variants. RESULTS: Our final dataset contained 204 families that were informative for at least one manifestation of BHD (67 families informative for skin manifestations, 63 for lung, 88 for renal carcinoma and 29 for polyps). By age 70 years, male carriers of the FLCN variant have an estimated 19% (95% CI 12% to 31%) risk of renal tumours, 87% (95% CI 80% to 92%) of lung involvement and 87% (95% CI 78% to 93%) of skin lesions, while female carriers had an estimated 21% (95% CI 13% to 32%) risk of renal tumours, 82% (95% CI 73% to 88%) of lung involvement and 78% (95% CI 67% to 85%) of skin lesions. The cumulative risk of colonic polyps by age 70 years old was 21% (95% CI 8% to 45%) for male carriers and 32% (95% CI 16% to 53%) for female carriers. CONCLUSIONS: These updated penetrance estimates, based on a large number of families, are important for the genetic counselling and clinical management of BHD syndrome.

Familial multiple discoid fibromas is linked to a locus on chromosome 5 including the FNIP1 gene.

Previously, we reported a series of families presenting with trichodiscomas, inherited in an autosomal dominant pattern. The phenotype was named familial multiple discoid fibromas (FMDF). The genetic cause of FMDF remained unknown so far. Trichodiscomas are skin lesions previously reported to be part of the same spectrum as the fibrofolliculoma observed in Birt-Hogg-Dubé syndrome (BHD), an inherited disease caused by pathogenic variants in the FLCN gene. Given the clinical and histological differences with BHD and the exclusion of linkage with the FLCN locus, the phenotype was concluded to be distinct from BHD. We performed extensive clinical evaluations and genetic testing in ten families with FMDF. We identified a FNIP1 frameshift variant in nine families and genealogical studies showed common ancestry for eight families. Using whole exome sequencing, we identified six additional rare variants in the haplotype surrounding FNIP1, including a missense variant in the PDGFRB gene that was found to be present in all tested patients with FMDF. Genome-wide linkage analysis showed that the locus on chromosome 5 including FNIP1 was the only region reaching the maximal possible LOD score. We concluded that FMDF is linked to a haplotype on chromosome 5. Additional evaluations in families with FMDF are required to unravel the exact genetic cause underlying the phenotype. When evaluating patients with multiple trichodisomas without a pathogenic variant in the FLCN gene, further genetic testing is warranted and can include analysis of the haplotype on chromosome 5.

Challenges in breast cancer genetic testing. A call for novel forms of multidisciplinary care and long-term evaluation.

Current methods of next generation sequencing may simultaneously detect multiple germline breast cancer susceptibility variants. However, it is a challenge to maximize the clinical benefit of genetic analysis for patients and family members while minimizing potentially harmful effects. Relevant issues include criteria for referral, the choice of gene panel, handling of variants of unknown significance, cancer risk counselling in clinical context including family history data, risks of tumours other than breast cancer, handling of potential germline findings revealed by tumour testing and the clinical management of gene variant carriers, including surveillance, targeted therapy, radiotherapy and risk-reducing surgery. We outline current challenges in the field of breast cancer genetics and call for novel forms of multidisciplinary care and long-term evaluation.

Oral contraceptive use and ovarian cancer risk for BRCA1/2 mutation carriers: an international cohort study.

BACKGROUND: Ovarian cancer risk in BRCA1 and BRCA2 mutation carriers has been shown to decrease with longer duration of oral contraceptive use. Although the effects of using oral contraceptives in the general population are well established (approximately 50% risk reduction in ovarian cancer), the estimated risk reduction in mutation carriers is much less precise because of potential bias and small sample sizes. In addition, only a few studies on oral contraceptive use have examined the associations of duration of use, time since last use, starting age, and calendar year of start with risk of ovarian cancer. OBJECTIVE: This study aimed to investigate in more detail the associations of various characteristics of oral contraceptive use and risk of ovarian cancer, to provide healthcare providers and carriers with better risk estimates. STUDY DESIGN: In this international retrospective study, ovarian cancer risk associations were assessed using oral contraceptives data on 3989 BRCA1 and 2445 BRCA2 mutation carriers. Age-dependent-weighted Cox regression analyses were stratified by study and birth cohort and included breast cancer diagnosis as a covariate. To minimize survival bias, analyses were left truncated at 5 years before baseline questionnaire. Separate analyses were conducted for each aspect of oral contraceptive use and in a multivariate analysis, including all these aspects. In addition, the analysis of duration of oral contraceptive use was stratified by recency of use. RESULTS: Oral contraceptives were less often used by mutation carriers who were diagnosed with ovarian cancer (ever use: 58.6% for BRCA1 and 53.5% BRCA2) than by unaffected carriers (ever use: 88.9% for BRCA1 and 80.7% for BRCA2). The median duration of use was 7 years for both BRCA1 and BRCA2 carriers who developed ovarian cancer and 9 and 8 years for unaffected BRCA1 and BRCA2 carriers with ovarian cancer, respectively. For BRCA1 mutation carriers, univariate analyses have shown that both a longer duration of oral contraceptive use and more recent oral contraceptive use were associated with a reduction in the risk of ovarian cancer. However, in multivariate analyses, including duration of use, age at first use, and time since last use, duration of oral contraceptive use proved to be the prominent protective factor (compared with <5 years: 5-9 years [hazard ratio, 0.67; 95% confidence interval, 0.40-1.12]; >10 years [hazard ratio, 0.37; 95% confidence interval, 0.19-0.73]; Ptrend=.008). The inverse association between duration of use and ovarian cancer risk persisted for more than 15 years (duration of ≥10 years; BRCA1 <15 years since last use [hazard ratio, 0.24; 95% confidence interval, 0.14-0.43]; BRCA1 >15 years since last use [hazard ratio, 0.56; 95% confidence interval, 0.18-0.59]). Univariate results for BRCA2 mutation carriers were similar but were inconclusive because of limited sample size. CONCLUSION: For BRCA1 mutation carriers, longer duration of oral contraceptive use is associated with a greater reduction in ovarian cancer risk, and the protection is long term.

The uptake of predictive DNA testing in 40 families with a pathogenic BRCA1/BRCA2 variant. An evaluation of the proband-mediated procedure.

When hereditary breast and ovarian cancer (HBOC) due to a BRCA1/BRCA2 germline pathogenic variant is diagnosed, the proband will be asked to inform other at-risk family members. In the Netherlands, a guideline was introduced in 2012 which provided detailed recommendations regarding this proband-mediated procedure. We now evaluated the uptake of predictive BRCA1/BRCA2 testing in 40 consecutive HBOC families diagnosed in our centre in 2014. We performed a retrospective observational study of all 40 families in which a pathogenic BRCA1/BRCA2 germline variant was identified during 2014. We scored the uptake of predictive and confirmatory testing by the end of 2018 and explored factors associated with the level of uptake. Two families were excluded. In the remaining 38 families, among 239 family members ≥18 years at 50% risk of being a mutation carrier or at 25% risk if the family member at 50% risk was deceased, 102 (43%) were tested. Among 108 females 25-75 years of age at 50% risk, 59 (55%) underwent predictive or confirmatory testing, and among 43 males at 50% risk with daughters ≥18 years, 22 (51%) were tested. Factors which complicated cascade screening included family members living abroad, probands not wanting to share information and limited pedigree information. In conclusion, the standard proband-mediated procedure of informing relatives seems to be far from optimal. We suggest a tailored approach for each family, including the option of a direct approach to at-risk family members by the geneticist. In addition, we suggest detailed monitoring and follow-up of families.

Do Preferred Risk Formats Lead to Better Understanding? A Multicenter Controlled Trial on Communicating Familial Breast Cancer Risks Using Different Risk Formats.

PURPOSE: Counselees' preferences are considered important for the choice of risk communication format and for improving patient-centered care. We here report on counselees' preferences for how risks are presented in familial breast cancer counseling and the impact of this preferred format on their understanding of risk. PATIENTS AND METHODS: As part of a practice-based randomized controlled trial, 326 unaffected women with a family history of breast cancer received their lifetime risk in one of five presentation formats after standard genetic counseling in three Dutch familial cancer clinics: 1) in percentages, 2) in frequencies ("X out of 100"), 3) in frequencies plus graphical format (10×10 human icons), 4) in frequencies and 10-year age-related risk and 5) in frequencies and 10-year age-related risk plus graphical format. Format preferences and risk understanding (accuracy) were assessed at 2-week follow-up by a questionnaire, completed by 279/326 women. RESULTS: The most preferred risk communication formats were numbers combined with verbal descriptions (37%) and numbers only (26%). Of the numerical formats, most (55%) women preferred percentages. The majority (73%) preferred to be informed about both lifetime and 10-year age-related risk. Women who had received a graphical display were more likely to choose a graphical display as their preferred format. There was no significant effect between the intervention groups with regard to risk accuracy. Overall, women given risk estimates in their preferred format had a slightly better understanding of risk. CONCLUSION: The results suggest that the accuracy of breast cancer risk estimation is slightly better for women who had received this information in their preferred format, but the risk format used had no effect on women's risk accuracy. To meet the most frequent preference, counselors should consider providing a time frame of reference (eg, risk in the next 10 years) in a numerical format, in addition to lifetime risk.

[BRCAmutations more frequent in people of Jewish ancestry]. / VakerBRCA-mutaties bij mensen van Joodse komaf.

Three BRCA1/BRCA2 mutations occur more frequently in the Jewish population than in the general population. In Jewish patients with breast cancer about 10% of cases are caused by one of these mutations; consequently, all patients with breast cancer and who are of Jewish ancestry, or their healthy family members, are eligible for genetic testing.