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Knowledge of population specific BRCA1/2 founder mutations provides a valuable and cost‐effective genetic testing strategy. Twenty‐three recurrent BRCA1 mutations have been identified previously in 100 Pakistani breast and/or ovarian cancer families. These accounted for 72.5% of all BRCA1 mutations identified. In our study, we investigated whether these mutations (identified in ≥2 unrelated patients) have a common ancestral origin and estimated the ages of these mutations. Haplotype analyses were performed in 188 individuals (100 index patients, 88 relatives) from Pakistani breast/ovarian cancer families, all harboring one of the 23 recurrent BRCA1 mutations, and 90 healthy controls. Six microsatellite markers (D17S800, D17S1801, D17S855, D17S1322, D17S1323, and D17S951) were analyzed. Mutation ages were estimated using DMLE+2.3 software. An identical haplotype of different length was found in families harboring the same BRCA1 mutation and suggested founder effects for all 23 mutations. Sixteen founder mutations were ethnicity‐specific: 15 occurred in families of Punjabi background and one in a family of Pathan background. The remaining seven mutations occurred in families with two ethnic backgrounds. All BRCA1 founder mutations were estimated to have arisen approximately 147 to 159 generations ago. Our findings suggest founder effects for all 23 recurrent BRCA1 mutations. This knowledge allows the design and development of a cost effective local genetic testing strategy in Pakistan. [ABSTRACT FROM AUTHOR]

Purpose: The co-occurrence or double heterozygosity of pathogenic/likely pathogenic sequence variants (P/LPSVs) in major cancer susceptibility genes has rarely been reported. Such co-occurrence raises the issues of accurate genetic counseling, preferred recommended surveillance scheme, and the use of preimplantation genetic diagnosis (PGD). Methods: A clinical report of an Ashkenazi Jewish (AJ) family with co occurrence of two PSVs in BRCA1 and TP53 and a literature search. Results: In an AJ family with a substantial history of cancer limited to the maternal side, two siblings co-harbored TP53 (c.733C>A; p.G245S) and the predominant 5266dup BRCA1 mutation, originating from the mother and the father, respectively. PGD is ongoing. Four families were thus far reported as double heterozygotes for both BRCA1/BRCA2 and TP53. Based on the limited available data, it seems that the phenotype in double PSV heterozygotes is not more severe than in single PSV carrier in either gene. Conclusions: This family highlights the need to genotype both parents, especially in populations with founder mutations, when a BRCA1 mutation is detected in an offspring, regardless of family history. The combination of mutations in these two genes presents a challenge for PGD since both genes are located on chromosome 17. [ABSTRACT FROM AUTHOR]

Abstract Background Founder mutations in the two breast cancer genes, BRCA1 and BRCA2, have been described in many populations, among these are Ashkenazi-Jewish, Polish, Norwegian and Icelandic. Founder mutation testing in patients with relevant ancestry has been a cost-efficient approach in such populations. Four Norwegian BRCA1 founder mutations were defined by haplotyping in 2001, and accounted for 68% of BRCA1 mutation carriers at the time. After 15 more years of genetic testing, updated knowledge on the mutation spectrum of both BRCA1 and BRCA2 in Norway is needed. In this study, we aim at describing the mutation spectrum and frequencies in the BRCA1/2 carrier population of the largest clinic of hereditary cancer in Norway. Methods A total of 2430 BRCA1 carriers from 669 different families, and 1092 BRCA2 carriers from 312 different families were included in a quality of care study. All variants were evaluated regarding pathogenicity following ACMG/ENIGMA criteria. The variants were assessed in AlaMut and supplementary databases to determine whether they were known to be founder mutations in other populations. Results There were 120 different BRCA1 and 87 different BRCA2 variants among the mutation carriers. Forty-six per cent of the registered BRCA1/2 families (454/981) had a previously reported Norwegian founder mutation. The majority of BRCA1/2 mutations (71%) were rare, each found in only one or two families. Fifteen per cent of BRCA1 families and 25% of BRCA2 families had one of these rare variants. The four well-known Norwegian BRCA1 founder mutations previously confirmed through haplotyping were still the four most frequent mutations in BRCA1 carriers, but the proportion of BRCA1 mutation carriers accounted for by these mutations had fallen from 68 to 52%, and hence the founder effect was weaker than previously described. Conclusions The spectrum of BRCA1 and BRCA2 mutations in the carrier population at Norway’s largest cancer genetics clinic is diverse, and with a weaker founder effect than previously described. As a consequence, retesting the families that previously have been tested with specific tests/founder mutation tests should be a prioritised strategy to find more mutation positive families and possibly prevent cancer in healthy relatives.

Screening programmes for BRCA1/2 Jewish Founder mutations (JFM) in the Jewish community have been advocated internationally. Implementation of these programmes could decrease morbidity and mortality of BRCA1/2 JFM carriers through the uptake of cancer screening strategies and risk-reducing surgery. An online programme offered to the Sydney Jewish community that delivers pre-test information and collects consent for BRCA1/2 JFM testing via a website is currently being evaluated (JeneScreen). Forty-three participants from JeneScreen were invited to participate in a sub-study, of semi-structured pre- and post-result telephone interviews. Eleven participants consented to the sub-study. The interviews explored their experiences regarding the online model of obtaining pre-test genetic information, giving consent and receiving results. Inductive thematic analysis was carried out on the interviews. Overarching themes identified include (1) embracing online testing, (2) the online pre-test experience, (3) the result notification experience, (4) concerns associated with online testing and (5) testing as a responsibility. Overall, participants were highly satisfied with online BRCA1/2 JFM testing, an indication that the a website for pre-test information provision is an acceptable alternative to in-person genetic counselling for BRCA1/2 JFM screening and represents a feasible model for future community screening efforts. [ABSTRACT FROM AUTHOR]

Purpose. To characterize the spectrum of BRCA1 and BRCA2 pathogenic germline variants in women from south-west Poland and west Ukraine affected with breast or ovarian cancer. Testing in women at high risk of breast and ovarian cancer in these regions is currently mainly limited to founder mutations. Methods. Unrelated women affected with breast and/or ovarian cancer from Poland (n = 337) and Ukraine (n = 123) were screened by targeted sequencing. Excluded from targeted sequencing were 34 Polish women who had previously been identified as carrying a founder mutation in BRCA1. No prior testing had been conducted among the Ukrainian women. Thus, this study screened BRCA1 and BRCA2 in the germline DNA of 426 women in total. Results. We identified 31 and 18 women as carriers of pathogenic/likely pathogenic (P/LP) genetic variants in BRCA1 and BRCA2, respectively. We observed five BRCA1 and eight BRCA2 P/LP variants (13/337, 3.9%) in the Polish women. Combined with the 34/337 (10.1%) founder variants identified prior to this study, the overall P/LP variant frequency in the Polish women was thus 14% (47/337). Among the Ukrainian women, 16/123 (13%) women were identified as carrying a founder mutation and 20/123 (16.3%) were found to carry non-founder P/LP variants (10 in BRCA1 and 10 in BRCA2). Conclusions. These results indicate that genetic testing in women at high risk of breast and ovarian cancer in Poland and Ukraine should not be limited to founder mutations. Extended testing will enhance risk stratification and management for these women and their families. [ABSTRACT FROM AUTHOR]

Background: Historically, three founder mutations in the BRCA1/2 (OMIM 113705; OMIM 600185) genes have been the focus of cancer risks within the Ashkenazi Jewish (AJ) population. However, there are several additional mutations associated with increased susceptibility to cancer in individuals of AJ ancestry. Methods: We report three patients who exemplify the need to keep these additional founder mutations in mind when pursuing hereditary cancer genetic testing of individuals in this population. All gene sequences in this paper were aligned to reference sequences based on human genome build GRCh37/UCSC hg19. Results: review of the literature discusses that the combined risk is 12.36%–20.83% forhaving 1 of the 10 hereditary cancer AJ founder mutations in the BRCA1, BRCA2, CHEK2 (OMIM 604373), APC (OMIM 611731), MSH2 (OMIM 609309), MSH6 (OMIM 600678), and GREM1 (OMIM 603054) genes for individuals of AJ ancestry. Conclusion: We recommend testing for all 10 of these AJ founder cancer susceptibility mutations for individuals within this population as standard screening in order to ensure appropriate cancer risk management and cascade testing. Historically, three founder mutations in the BRCA1/2 genes have been the focus of cancer risks within the Ashkenazi Jewish (AJ) population. However, there are several additional mutations associated with increased susceptibility to cancer in individuals of AJ ancestry. We report three patients who exemplify the need to keep these additional founder mutations in mind when pursuing hereditary cancer genetic testing in this population. A review of the literature discusses that the combined risk of having 1 of the 10 hereditary cancer AJ founder mutations in the BRCA1, BRCA2, CHEK2, APC, MSH2, MSH6, and GREM1 genes for individuals of AJ ancestry is 12.36%–20.83%. We recommend testing for all 10 of these AJ founder cancer susceptibility mutations for individuals within this population as standard screening in order to ensure appropriate cancer risk management and cascade testing. [ABSTRACT FROM AUTHOR]

Background: Founder mutations in the two breast cancer genes, BRCA1 and BRCA2, have been described in many populations, among these are Ashkenazi-Jewish, Polish, Norwegian and Icelandic. Founder mutation testing in patients with relevant ancestry has been a cost-efficient approach in such populations. Four Norwegian BRCA1 founder mutations were defined by haplotyping in 2001, and accounted for 68% of BRCA1 mutation carriers at the time. After 15 more years of genetic testing, updated knowledge on the mutation spectrum of both BRCA1 and BRCA2 in Norway is needed. In this study, we aim at describing the mutation spectrum and frequencies in the BRCA1/2 carrier population of the largest clinic of hereditary cancer in Norway. Methods: A total of 2430 BRCA1 carriers from 669 different families, and 1092 BRCA2 carriers from 312 different families were included in a quality of care study. All variants were evaluated regarding pathogenicity following ACMG/ENIGMA criteria. The variants were assessed in AlaMut and supplementary databases to determine whether they were known to be founder mutations in other populations. Results: There were 120 different BRCA1 and 87 different BRCA2 variants among the mutation carriers. Forty-six per cent of the registered BRCA1/2 families (454/981) had a previously reported Norwegian founder mutation. The majority of BRCA1/2 mutations (71%) were rare, each found in only one or two families. Fifteen per cent of BRCA1 families and 25% of BRCA2 families had one of these rare variants. The four well-known Norwegian BRCA1 founder mutations previously confirmed through haplotyping were still the four most frequent mutations in BRCA1 carriers, but the proportion of BRCA1 mutation carriers accounted for by these mutations had fallen from 68 to 52%, and hence the founder effect was weaker than previously described. Conclusions: The spectrum of BRCA1 and BRCA2 mutations in the carrier population at Norway's largest cancer genetics clinic is diverse, and with a weaker founder effect than previously described. As a consequence, retesting the families that previously have been tested with specific tests/founder mutation tests should be a prioritised strategy to find more mutation positive families and possibly prevent cancer in healthy relatives. [ABSTRACT FROM AUTHOR]

Prostate cancer (PrCa) is one of the most common cancers diagnosed worldwide and 5-10 % of all cases are estimated to be associated with inherited predisposition. Even though there is strong evidence that the genetic component is significant in PrCa, the genetic etiology of familial and early-onset disease is largely unknown. Although it has been suggested that men from families with hereditary breast/ovarian cancer (HBOC) and, more recently, with Lynch syndrome may have an increased risk for PrCa, the contribution of these syndromes to PrCa predisposition in families ascertained for early-onset and/or familial PrCa, independently of the presence of other cancers in the family, is uncertain. To quantify the contribution of genes associated with HBOC and Lynch syndromes to PrCa predisposition, we have tested for germline mutations 460 early-onset and/or familial PrCa patients. All patients were screened for the six mutations that are particularly common in Portugal and 38 of them were selected for complete sequencing of BRCA1/ 2 and/or MLH1, MSH2 and MSH6. Two patients were found to harbor the same MSH2 mutation and a third patient carried a Portuguese BRCA2 founder mutation. None of the alterations were identified in 288 control subjects. Furthermore, we reviewed the 62 PrCa diagnoses in all HBOC (n = 161) and Lynch syndrome (n = 124) families previously diagnosed at our department, and found five other BRCA2 mutation carriers and two additional MSH2 mutation carriers. The clinicopathological characteristics of mutation carriers are in concordance with earlier data suggesting an aggressive PrCa phenotype and support the hypothesis that mutation carriers might benefit from targeted screening according to the gene mutated in the germline. [ABSTRACT FROM AUTHOR]

An estimated 1:40 individuals of Ashkenazi Jewish (AJ) ancestry carry one of three common founder mutations in BRCA1 or BRCA2, resulting in the inherited cancer condition, Hereditary Breast and Ovarian Cancer (HBOC) syndrome. Targeted testing for these three mutations ( BRCA1 187delAG, BRCA1 5385insC, and BRCA2 6174delT) is therefore recommended for all AJ breast and ovarian cancer patients, regardless of age of diagnosis or family history. Comprehensive analysis of both genes is recommended for a subset of AJ patients in whom founder mutations are not identified, but estimates of the yield from comprehensive analysis in this population vary widely. We sought to determine the proportion of non-founder mutations as a percentage of all mutations in BRCA1 and BRCA2 among AJ patients to inform decisions about HBOC testing strategies in this population. We analyzed the genetic testing results for 37,952 AJ patients for whom clinical testing of BRCA1 and BRCA2 was performed at Myriad Genetic Laboratories from January 2006 through August 2013. Analysis was limited to AJ-only patients for whom the initial test order was either (1) comprehensive testing, or (2) founder mutation testing with instructions to automatically 'reflex' to comprehensive analysis if negative. Cases were excluded if a separate follow-up order was placed to reflex to comprehensive analysis only after the founder mutation testing was reported out as negative. Among all BRCA1 and BRCA2 mutations detected in these groups, the percentage of non-founder mutations was 13 % (104/802) and 7.2 % (198/2,769). One-hundred and eighty-nine unique non-founder mutations were detected, 76 in BRCA1 and 113 in BRCA2. Non-founder mutations make up between 7.2 and 13.0 % of all BRCA1 and BRCA2 mutations in Ashkenazi Jews. A wide range of mutations are present, most of which are also seen in non-AJ individuals. [ABSTRACT FROM AUTHOR]

BRCA1-associated breast cancer is considered an unique clinical entity with its own specific histopathological characteristics. Several recently published large studies have shown that overall survival of BRCA1 mutation carriers having breast cancer is similar to sporadic breast cancer patients. It was also suggested that better response to chemotherapy is one of the most important factors that improves the clinical outcome of breast cancers with unfavorable histopathological subtypes in BRCA1 mutation carriers. Adjuvant! Online and PREDICT are web-based prognostic tools that estimate the survival benefit of adjuvant chemotherapy in primary breast cancer patients. These tools have been extensively validated in different populations; however, the accuracy of the predictions made by Adjuvant! Online and PREDICT among BRCA1 mutation carriers has not yet been investigated. In this study we have found, that predictions of overall and breast cancer-specific survival obtained from Adjuvant! Online and PREDICT were significantly lower than the observed survival percentages in the study population [predicted—observed difference for 10–year overall survival: −9.75 %, P < 0.0001 (Adjuvant! Online); −10.21 %, P < 0.0001 (PREDICT)]. Thus this study suggests that Adjuvant! Online and PREDICT should be used with caution in this group of patients. Further updating of adjuvant therapy benefit calculation tools by inclusion of the information about inherited genetic alterations should be considered to improve the performance of the prognostic programs among hereditary breast cancer patients. [ABSTRACT FROM AUTHOR]

Abstract: Uncertainty exists about the origin of BRCA1 c.4035delA mutation which is prevalent in Baltic countries, with the highest frequency being in Lithuania (53% of all BRCA1 mutations), although formal founder mutation analysis by haplotype has not yet been undertaken. In this study we genotyped 78 unrelated BRCA1 c.4035delA mutation carriers families from Lithuania, Latvia, Poland and Russia. The results from the haplotype analyses were used to estimate the age of the mutation. Using maximum likelihood methods we estimated that the mutation arose approximately 1550 years (62 generations of 25 years) ago (ca. 5th century) somewhere in the present territory of Lithuania, in the area inhabited by ancient Baltic tribes at that time. Our results show that this mutation gradually entered the gene pool in the neighboring countries. [Copyright &y& Elsevier]

Bogdanova NV, Antonenkova NN, Rogov YI, Karstens JH, Hillemanns P, Dörk T. High frequency and allele-specific differences of BRCA1 founder mutations in breast cancer and ovarian cancer patients from Belarus. Breast cancer and ovarian cancer are common malignancies in Belarus accounting for about 3500 and 800 new cases per year, respectively. For breast cancer, the rates and age of onset appear to vary significantly in regions differentially affected by the Chernobyl accident. We assessed the frequency and distribution of three BRCA1 founder mutations 5382insC, 4153delA and Cys61Gly in two hospital-based series of 1945 unselected breast cancer patients and of 201 unselected ovarian cancer patients from Belarus as well as in 1019 healthy control females from the same population. Any of these mutations were identified in 4.4% of the breast cancer patients, 26.4% of the ovarian cancer patients and 0.5% of the controls. In the breast cancer patients, BRCA1 mutations were strongly associated with earlier age at diagnosis, with oestrogen receptor (ER) negative tumours and with a first-degree family history of breast cancer, although only 35% of the identified BRCA1 mutation carriers had such a family history. There were no marked differences in the regional distribution of BRCA1 mutations, so that the significant differences in age at diagnosis and family history of breast cancer patients from areas afflicted by the Chernobyl accident could not be explained by BRCA1. We next observed a higher impact and a shifted mutational spectrum of BRCA1 in the series of Byelorussian ovarian cancer patients where the three founder mutations accounted for 26.4% (53/201). While the Cys61Gly mutation appeared underrepresented in ovarian cancer as compared with breast cancer cases from the same population (p = 0.01), the 4153delA mutation made a higher contribution to ovarian cancer than to breast cancer (p < 0.01). BRCA1 mutations were significantly enriched among ovarian cancer cases with a first-degree family history of breast or ovarian cancer, whereas the median age at ovarian cancer diagnosis was not different between mutation carriers and non-carriers. Taken together, these results identify three BRCA1 founder mutations as key components of inherited breast and ovarian cancer susceptibility in Belarus and might have implications for cancer prevention, treatment and genetic counselling in this population. [ABSTRACT FROM AUTHOR]

The mutation spectrum of BRCA1 and BRCA2 presents a wide range of unique mutations in breast/ovarian cancer patients but recurrent mutations with founder effects have also been described. BRCA2 5344delAATA and 9538delAA are recurrent mutations in Castilla-León (Spain) representing 10.6% of BRCA2 positive families. By genotyping eleven chromosome 13 markers (4.3 Mb) we demonstrate that each mutation shows core haplotypes of 1.66 and 0.87 Mb, respectively, supporting a common ancestor in Castilla-León. Furthermore, both mutations are associated with earlier onset of breast cancer (5344delAATA: 37.4 years, P = 0.033; 9538delAA: 39.4 years, P = 0.008). The identification of founder effects improves the genetic screening strategy to be followed and facilitates the clinical management of asymptomatic carriers [ABSTRACT FROM AUTHOR]

Infante M, Durán M, Acedo A, Pérez-Cabornero L, Sanz DJ, García-González M, Beristain E, Esteban-Cardeñosa E, de la Hoya M, Teulé A, Vega A, Tejada M-I, Lastra E, Miner C, Velasco EA. BRCA1 5272-1G>A and BRCA2 5374delTATG are founder mutations of high relevance for genetic counselling in breast/ovarian cancer families of Spanish origin. The distribution of BRCA1 and BRCA2 germ line mutations in breast/ovarian cancer families varies among different populations, which typically present a wide spectrum of unique mutations. Splicing mutation 5272-1G>A of BRCA1 and frameshift mutation 5374delTATG of BRCA2 are highly prevalent mutations in Castilla-León (Spain), accounting for 18.4% and 13.6% of BRCA1 and BRCA2 positive families, respectively. To test the presence of founder effects, 9 Spanish 5272-1G>A and 13 5374delTATG families were genotyped with polymorphic markers linked to BRCA1 or BRCA2. All the 5272-1G>A families shared a common haplotype in eight markers (1.1 Mb region) and the mutation age was estimated in 15 generations (∼380 years). A conserved haplotype associated to 5374delTATG was observed in four markers (0.82 Mb). The mutation occurred approximately 48 generations ago (∼1200 years). Each mutation likely arose from a common ancestor that could be traced to a small area of Castilla-León and expanded to other Spanish regions. They can have a significant impact on the clinical management of asymptomatic carriers as well as on the genetic screening strategy to be followed in populations with Spanish ancestries. [ABSTRACT FROM AUTHOR]

Abstract: Ten BRCA mutations were demonstrated to be frequent in the Norwegian population. We present maps verifying the uneven distribution of prevalences according to municipality. We tested incident breast cancer cases treated in Mid-Norway from 1999 onwards for these mutations. Uptake of testing was 97% and 2.5% were demonstrated to be mutation carriers. Ten (77%) were outside families previously known to carry a mutation. Ten (77%) did not meet clinical criteria to be selected for mutation testing. We tested incident ovarian cancer cases in South-West Norway from 2001 onwards. Uptake of testing was 80% and 23% were mutation carriers. Twenty-one (88%) were outside families previously known. Twelve (67%) did not meet clinical criteria to be selected for testing. All patients with mutation collaborated actively to give our offer of predictive genetic testing to their relatives. No complaint on the activity was received. [Copyright &y& Elsevier]

The frequency of BRCA1 and BRCA2 mutations in women with breast cancer varies according to the age at diagnosis, family history of cancer, and ethnicity/country of origin. We set out to estimate the frequency of seven previously described founder mutations in BRCA1 and BRCA2 in all eligible French Canadian women diagnosed with invasive breast cancer at one Montreal hospital over a 20-month period. One hundred and ninety-two patients were eligible and 127 (66.2%) provided blood for genetic testing. We identified 4 women who carried a founder mutation (3.1%, 95% confidence interval 0.9–7.9%) in this population. Interestingly, all the mutations were in BRCA2. The mean age at diagnosis for mutation carriers was 51.2 years (range 49.1–53.5). Two of these 4 cases were lobular invasive carcinomas and 2 were ductal carcinomas, histological grade 1 or 2. Despite a small tumor size (≤20 mm), axillary nodal involvement was present in 3 women. Estrogen receptors were strongly expressed in all cases. Two of the 4 cases reported a strong family history of breast cancer, but a family history of site-specific breast cancer was a relatively poor indicator of the presence of BRCA2 mutations. The absence of BRCA1 mutations may be a result of chance, but may also reflect different geographical origins of the most common BRCA1 mutations within the French Canadian population. [ABSTRACT FROM AUTHOR]

Abstract Background Relatives of BRCA1 and BRCA2 mutation carriers have long been proposed by epidemiological studies to have an increased risk of developing prostate cancer. In the Ashkenazi Jewish (AJ) population, the existence of 3 frequent founder mutations, 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 greatly facilitates screening for carriers. Methods We tested 146 AJ men with confirmed diagnoses of invasive prostate cancer. Thirteen had at least one first degree relative with prostate cancer. The median age at diagnosis of participants was 67.9 years (range 48.6–84.2 years). Subjects were screened for the BRCA1:185delAG, BRCA1:5382insC and BRCA2:6174delT mutations simultaneously using a multiplex sizing assay detecting band shifts in the presence of the variant sequence. Results Two out of 146 individuals were found to carry the germline BRCA2 mutation 6174delT (1.4%); the previously reported population frequency for this mutation is ~1% in AJ. We found no BRCA1 mutations. One carrier had 2 uncles affected with prostate cancer, while the other had an uncle and daughter with breast cancer. We combined our results with previously published data examining these 3 founder AJ mutations in men with prostate cancer and in population controls. Including our results, studies to date reported 5/463 (1.1%), 2/293 (0.68%) and 7/461 (1.3%) carriers for the BRCA1:185delAG, BRCA1:5382insC and BRCA2:6174delT mutations in prostate cancer cases, respectively. This compares with combined reported frequencies of 85/9371 (0.91%), 24/8867 (0.27%) and 119/9514 (1.3%) for the same mutations in control individuals. There was no statistically significant excess of mutations in cases compared to controls in either gene. Conclusions Our observations remain preliminary. By combining all studies published to date, we have an 80% power to detect ORs of 2.7, 6.6 and 2.5 (185delAG, 5382insC and 6174 delT, respectively) while the values we observed range between 1.0 and 2.5. However, the contribution of rare mutations with such low odds ratios to the population prostate cancer burden is unlikely to be large enough to be clinically useful. Thus, contrary to suggestions from some previous epidemiological data, our observations do not support an important role for AJ founder BRCA1/2 mutations in prostate cancer risk.