Mutations in WNT10A are present in more than half of isolated hypodontia cases van den Boogaard, Marie-Jose; Creton, Marijn; Bronkhorst, Yvon; van der Hout, Annemieke; Hennekam, Eric; Lindhout, Dick; Cune, Marco; van Amstel, Hans Kristian Ploos Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Results WNT10A mutations were identified in 56% of the cases with non-syndromic hypodontia. MSX1, PAX9 and AXIN2 mutations were present in 3%, 9% and 3% of the cases, respectively. Conclusion The authors identified WNT10A as a major gene in the aetiology of isolated hypodontia. By including WNT10A in the DNA diagnostics of isolated tooth agenesis, the yield of molecular testing in this condition was significantly increased from 15% to 71%.

BackgroundIn recent years, the amount of genomic data produced in clinical genetics services has increased significantly due to the advent of next-generation sequencing. This influx of genomic information leads to continuous changes in knowledge on how genetic variants relate to hereditary disease. These changes can have important consequences for patients who have had genetic testing in the past, as new information may affect their clinical management. When and how patients should be recontacted after new genetic information becomes available has been investigated extensively. However, the issue of how to handle the changing nature of genetic information remains underexplored in a laboratory setting, despite it being the first stage at which changes in genetic data are identified and managed.MethodsThe authors organized a 7-day online focus group discussion. Fifteen clinical laboratory geneticists took part. All (nine) Dutch clinical molecular genetics diagnostic laboratories were represented.ResultsLaboratories in our study reinterpret genetic variants reactively, e.g. at the request of a clinician or following identification of a previously classified variant in a new patient. Participants currently deemed active, periodic reinterpretation to be unfeasible and opinions differed on whether it is desirable, particularly regarding patient autonomy and the main responsibilities of the laboratory. The efficacy of reinterpretation was questioned in the presence of other strategies, such as reanalysis and resequencing of DNA. Despite absence of formal policy regarding when to issue a new report for clinicians due to reclassified genetic data, participants indicated similar practice across all laboratories. However, practice differed significantly between laboratory geneticists regarding the reporting of VUS reclassifications.ConclusionBased on the results, the authors formulated five challenges needing to be addressed in future laboratory guidelines: 1. Should active reinterpretation of variants be conducted by the laboratory as a routine practice? 2. How does reinterpretation initiated by the laboratory relate to patient expectations and consent? 3. When should reinterpreted data be considered clinically significant and communicated from laboratory to clinician? 4. Should reinterpretation, reanalysis or a new test be conducted? 5. How are reclassifications perceived and how might this affect laboratory practice?

Sarcomas, including the malignant fibrous histiocytomas (MFHs), are not known to be part of the tumour spectrum of hereditary non‐polyposis colorectal cancer (HNPCC) as epidemiologically established. Therefore, occurrence of MFH in an HNPCC family may very well be coincidental. HNPCC is associated with germline mutations in DNA mismatch repair genes, including the MSH2 gene. We analysed an MFH diagnosed in a 45‐year‐old male HNPCC patient carrying a germline MSH2 mutation for HNPCC‐associated molecular characteristics, to investigate a possible relationship between the tumour and that mutation. DNA analysis revealed microsatellite instability and loss of one MSH2 copy, and immunohistochemistry showed absence of nuclear MSH2 protein staining. To investigate whether this is a common finding in MFH, microsatellite instability and nuclear MSH2 protein staining was tested for in 5 and 6 sporadic MFHs, respectively. None showed microsatellite instability and all stained positively for MSH2. Together, these findings show that in rare cases, MFH may be part of the HNPCC tumour spectrum. © 2000 Wiley‐Liss, Inc.

Background. In recent years, the amount of genomic data produced in clinical genetics services has increased significantly due to the advent of next-generation sequencing. This influx of genomic information leads to continuous changes in knowledge on how genetic variants relate to hereditary disease. These changes can have important consequences for patients who have had genetic testing in the past, as new information may affect their clinical management. When and how patients should be recontacted after new genetic information becomes available has been investigated extensively.However, the issue of how to handle the changing nature of genetic information is significantly underexplored in a laboratory setting, despite it being the first stage at which changes in genetic data are identified and managed. Methods. The authors organized a 7-day online focus group discussion in which all Dutch molecular genetics diagnostic laboratories were represented. Results. Laboratories in our study reinterpret genetic variants reactively, e.g. at the request of a clinician or following identification of a previously classified variant in a new patient. Participants currently deemed active, periodic reinterpretation to be unfeasible and opinions differed on whether it is desirable, particularly in regard to patient autonomy and the main responsibilities of the laboratory. The efficacy of reinterpretation was questioned in the presence of other strategies, such as reanalysis and resequencing of DNA. Despite absence of formal policy regarding when to issue a new report for clinicians due to reclassified genetic data, participants indicated similar practice across all laboratories. However, practice differed significantly between laboratory geneticists regarding the reporting of VUS reclassifications. Conclusion. Based on the results, the authors formulated five challenges needing to be addressed in future laboratory guidelines: 1. Should active reinterpretation of variants be conducted by the laboratory as a routine practice? 2. How does reinterpretation initiated by the laboratory relate to patient expectations and consent? 3. When should reinterpreted data be considered clinically significant and communicated from laboratory to clinician? 4. Should reinterpretation, reanalysis or a new test be conducted? 5. How are reclassifications perceived and how might this affect laboratory practice?

This observational study aimed to investigate whether the reported association between family history (FH) of breast cancer (BC) or ovarian cancer (OC) and OC risks in BRCA1/2 mutation carriers can be explained by mutation position on the gene. In total, 3310 female BRCA1/2 mutation carriers participating in a nationwide prospective cohort (Hereditary Breast and Ovarian Cancer in the Netherlands) were included. FH was classified according to cancer occurrence in first-degree relatives (BC only, OC only, both, neither) and mutations were classified according to their position on the gene (OC cluster region (OCCR), BC cluster region, neither). The main outcome was OC occurrence. Cox proportional-hazard models were applied to investigate the association between FH and OC risks before and after adjusting for mutation position. Of all women included, 202 were diagnosed with OC. A BC-only FH tended to be associated with lower OC risks when compared with a FH without BC/OC (HR: 0.79, 95% CI: 0.52-1.17; HR: 0.59, 95% CI: 0.33-1.07 for BRCA1 and BRCA2, respectively) while an OC-only FH tended to be associated with higher risks (HR: 1.58, 95% CI: 0.90-2.77; HR: 1.75, 95% CI: 0.70-4.37 for BRCA1 and BRCA2, respectively). After adjusting for mutation position, association between FH and OC risks was slightly smaller in magnitude (HR: 0.85, 95% CI: 0.55-1.30; HR: 0.64, 95% CI: 0.34-1.21 for BC-only FH in BRCA1 and BRCA2, respectively; HR: 1.46, 95% CI: 0.80-2.68; HR: 1.49, 95% CI: 0.44-4.02 for OC-only FH in BRCA1 and BRCA2, respectively), indicating that mutation position explains only part of the association. Considering the magnitude of the observed trend, we do not believe FH should be used to change counseling regarding OC prevention.