Margriet J. Collee

Mutations in SMAD3 cause a syndromic form of aortic aneurysms and dissections with early-onset osteoarthritis

Thoracic aortic aneurysms and dissections are a main feature of connective tissue disorders, such as Marfan syndrome and Loeys-Dietz syndrome. We delineated a new syndrome presenting with aneurysms, dissections and tortuosity throughout the arterial tree in association with mild craniofacial features and skeletal and cutaneous anomalies. In contrast with other aneurysm syndromes, most of these affected individuals presented with early-onset osteoarthritis. We mapped the genetic locus to chromosome 15q22.2–24.2 and show that the disease is caused by mutations in SMAD3. This gene encodes a member of the TGF-β pathway that is essential for TGF-β signal transmission. SMAD3 mutations lead to increased aortic expression of several key players in the TGF-β pathway, including SMAD3. Molecular diagnosis will allow early and reliable identification of cases and relatives at risk for major cardiovascular complications. Our findings endorse the TGF-β pathway as the primary pharmacological target for the development of new treatments for aortic aneurysms and osteoarthritis.

Breast and ovarian cancer risks in a large series of clinically ascertained families with a high proportion of BRCA1 and BRCA2 Dutch founder mutations

Background BRCA1 or BRCA2 mutations confer increased risks of breast and ovarian cancer, but risks have been found to vary across studies and populations. Methods We ascertained pedigree data of 582 BRCA1 and 176 BRCA2 families and studied the variation in breast and ovarian cancer risks using a modified segregation analysis model. Results The average cumulative breast cancer risk by age 70 years was estimated to be 45% (95% CI 36 to 52%) for BRCA1 and 27% (95% CI 14 to 38%) for BRCA2 mutation carriers. The corresponding cumulative risks for ovarian cancer were 31% (95% CI 17 to 43%) for BRCA1 and 6% (95% CI 2 to 11%) for BRCA2 mutation carriers. In BRCA1 families, breast cancer relative risk (RR) increased with more recent birth cohort (pheterogeneity = 0.0006) and stronger family histories of breast cancer (pheterogeneity<0.001). For BRCA1, our data suggest a significant association between the location of the mutation and the ratio of breast to ovarian cancer (p<0.001). By contrast, in BRCA2 families, no evidence was found for risk heterogeneity by birth cohort, family history or mutation location. Conclusions BRCA1 mutation carriers conferred lower overall breast and ovarian cancer risks than reported so far, while the estimates of BRCA2 mutations were among the lowest. The low estimates for BRCA1 might be due to older birth cohorts, a moderate family history, or founder mutations located within specific regions of the gene. These results are important for a more accurate counselling of BRCA1/2 mutation carriers.

Rare variants in XRCC2 as breast cancer susceptibility alleles

Background Recently, rare germline variants in XRCC2 were detected in non-BRCA1/2 familial breast cancer cases, and a significant association with breast cancer was reported. However, the breast cancer risk associated with these variants needs further evaluation. Methods The coding regions and exon–intron boundaries of XRCC2 were scanned for mutations in an international cohort of 3548 non-BRCA1/2 familial breast cancer cases and 1435 healthy controls using various mutation scanning methods. Predictions on functional relevance of detected missense variants were obtained from three different prediction algorithms. Results The only protein-truncating variant detected was found in a control. Rare non-protein-truncating variants were detected in 20 familial cases (0.6%) and nine healthy controls (0.6%). Although the number of variants predicted to be damaging or neutral differed between prediction algorithms, in all instances these categories were evenly represented among cases and controls. Conclusions Our data do not confirm an association between XRCC2 variants and breast cancer risk, although a relative risk smaller than two could not be excluded. Variants in XRCC2 are unlikely to explain a substantial proportion of familial breast cancer.

The unfolding clinical spectrum of holoprosencephaly due to mutations in SHH, ZIC2, SIX3 and TGIF genes

Holoprosencephaly is a severe malformation of the brain characterized by abnormal formation and separation of the developing central nervous system. The prevalence is 1:250 during early embryogenesis, the live-born prevalence is 1:16 000. The etiology of HPE is extremely heterogeneous and can be teratogenic or genetic. We screened four known HPE genes in a Dutch cohort of 86 non-syndromic HPE index cases, including 53 family members. We detected 21 mutations (24.4%), 3 in SHH, 9 in ZIC2 and 9 in SIX3. Eight mutations involved amino-acid substitutions, 7 ins/del mutations, 1 frame-shift, 3 identical poly-alanine tract expansions and 2 gene deletions. Pathogenicity of mutations was presumed based on de novo character, predicted non-functionality of mutated proteins, segregation of mutations with affected family-members or combinations of these features. Two mutations were reported previously. SNP array confirmed detected deletions; one spanning the ZIC2/ZIC5 genes (approx. 100 kb) the other a 1.45 Mb deletion including SIX2/SIX3 genes. The mutation percentage (24%) is comparable with previous reports, but we detected significantly less mutations in SHH: 3.5 vs 10.7% (P=0.043) and significantly more in SIX3: 10.5 vs 4.3% (P=0.018). For TGIF1 and ZIC2 mutation the rate was in conformity with earlier reports. About half of the mutations were de novo, one was a germ line mosaic. The familial mutations displayed extensive heterogeneity in clinical manifestation. Of seven familial index patients only two parental carriers showed minor HPE signs, five were completely asymptomatic. Therefore, each novel mutation should be considered as a risk factor for clinically manifest HPE, with the caveat of reduced clinical penetrance.

The counselees' self-reported request for psychological help in genetic counseling for hereditary breast/ovarian cancer: not only psychopathology matters

Several studies have shown that counselees do not experience psychopathological levels of distress after DNA test result disclosure. However, it has not systematically been studied whether the absence of psychopathology also means that counselees do not want to receive help. Their self‐reported request for help may be related not only with psychopathology/distress but also with other psychological needs (e.g., surgery decisions), genetics‐specific needs (e.g., feeling vulnerable/stigmatized), and existential concerns (e.g., meaning in life).

RAD51B in Familial Breast Cancer

Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259) and population controls (n = 3586) from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR): 1.15, 95% confidence interval (CI): 1.11–1.19, P = 8.88 x 10−16) and among familial cases (OR: 1.24, 95% CI: 1.16–1.32, P = 6.19 x 10−11), compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk.

Variation in Mutation Spectrum Partly Explains Regional Differences in the Breast Cancer Risk of Female BRCA Mutation Carriers in the Netherlands

Background: We aimed to quantify previously observed relatively high cancer risks in BRCA2 mutation carriers (BRCA2 carriers) older than 60 in the Northern Netherlands, and to analyze whether these could be explained by mutation spectrum or population background risk. Methods: This consecutive cohort study included all known pathogenic BRCA1/2 carriers in the Northern Netherlands (N = 1,050). Carrier and general reference populations were: BRCA1/2 carriers in the rest of the Netherlands (N = 2,013) and the general population in both regions. Regional differences were assessed with HRs and ORs. HRs were adjusted for birth year and mutation spectrum. Results: All BRCA1 carriers and BRCA2 carriers younger than 60 had a significantly lower breast cancer risk in the Northern Netherlands; HRs were 0.66 and 0.64, respectively. Above age 60, the breast cancer risk in BRCA2 carriers in the Northern Netherlands was higher than in the rest of the Netherlands [HR, 3.99; 95% confidence interval (CI), 1.11–14.35]. Adjustment for mutational spectrum changed the HRs for BRCA1, BRCA2 <60, and BRCA2 ≥60 years by −3%, +32%, and +11% to 0.75, 0.50, and 2.61, respectively. There was no difference in background breast cancer incidence between the two regions (OR, 1.03; 95% CI, 0.97–1.09). Conclusions: Differences in mutation spectrum only partly explain the regional differences in breast cancer risk in BRCA2 carriers, and for an even smaller part in BRCA1 carriers. Impact: The increased risk in BRCA2 carriers older than 60 may warrant extension of intensive breast screening beyond age 60. Cancer Epidemiol Biomarkers Prev; 23(11); 2482–91. ©2014 AACR.

Abstract 2793: Not HOXB13 p.G84E, but p.R217C appears to be associated with increased breast cancer risk in the Dutch population

Recently, the germline mutation G84E in HOXB13 was shown to be associated with an increased risk for prostate cancer. In breast cancer, HOXB13 has been found to be overexpressed. Moreover, high expression of HOXB13 has been shown to mediate poor response to tamoxifen therapy by suppressing estrogen receptor α and inducing IL-6 expression. Based on these observations, the HOXB13 G84E mutation might also be associated with breast cancer risk. So far, the association between HOXB13 G84E and breast cancer risk has been investigated in three different studies and contradictory results were obtained. The goal of this study is to detect if HOXB13 gene mutations in general associate with breast cancer risk. To this end, we sequenced the whole HOXB13 coding region to find mutations in 1250 non-BRCA1&2 familial breast cancer cases and 800 controls. In total, thirteen variants were detected, including seven missense mutations. The G84E mutation was identified in 4 of 1215 cases (0.33%) and 6 of 759 controls (0.79%). Interestingly, we detected another mutation G217C in 6 of 1206 cases (0.50%) and 1 of 765 controls (0.13%). The other five missense mutations were only found once. Because both the HOXB13 G84E and R217C mutations were predicted to be probably damaging, we further evaluated if these two mutations were associated with breast cancer risk. Therefore we expanded our case-control study to include a total of 4520 non-BRCA1&2 familial breast cancer cases and 3127 controls by Taqman genotyping. Our preliminary results show that the HOXB13 G84E mutation was found in 22 of 4449 cases (0.49%) and 23 of 3089 controls (0.74%). The carrier allele frequency was higher in controls than in cases, but not significantly different (OR = 0.66, 95% CI = 0.37-1.19, p = 0.17). Our results indicate that the HOXB13 G84E mutation is not associated with breast cancer risk. The HOXB13 R217C mutation was identified in 15 of 4478 cases (0.33%) and 3 of 3077 controls (0.10%). This difference was borderline significant (OR = 3.44, 95% CI = 1.00-11.91, p = 0.052) most likely due to low population frequency in combination with a relatively small sample size. The HOXB13 R217C mutation could thus be a novel moderate-risk breast cancer susceptibility allele, however a larger study is needed to confirm these results. In conclusion, the R217C mutation rather than the G84E mutation in HOXB13 appears to be associated with breast cancer risk. Citation Format: Jingjing Liu, Wendy JC Prager-van der Smissen, Sten Cornelissen, Margriet J. Collee, Ans W.M. van den Ouweland, Marjanka K. Schmidt, John W.M. Martens, Antoinette Hollestelle. Not HOXB13 p.G84E, but p.R217C appears to be associated with increased breast cancer risk in the Dutch population. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2793. doi:10.1158/1538-7445.AM2015-2793

The counselees' self-reported request for psychological help in genetic counseling for hereditary breast/ovarian cancer: not only psychopathology matters: Self-reported need for psychological help in genetic counseling

Several studies have shown that counselees do not experience psychopathological levels of distress after DNA test result disclosure. However, it has not systematically been studied whether the absence of psychopathology also means that counselees do not want to receive help. Their self‐reported request for help may be related not only with psychopathology/distress but also with other psychological needs (e.g., surgery decisions), genetics‐specific needs (e.g., feeling vulnerable/stigmatized), and existential concerns (e.g., meaning in life).

The counselees' self-reported request for psychological help in genetic counseling for hereditary breast/ovarian cancer

Several studies have shown that counselees do not experience psychopathological levels of distress after DNA test result disclosure. However, it has not systematically been studied whether the absence of psychopathology also means that counselees do not want to receive help. Their self‐reported request for help may be related not only with psychopathology/distress but also with other psychological needs (e.g., surgery decisions), genetics‐specific needs (e.g., feeling vulnerable/stigmatized), and existential concerns (e.g., meaning in life).