Population screening for BRCA1/BRCA2 mutations: lessons from qualitative analysis of the screening experience

PurposePopulation screening for BRCA1/BRCA2. mutations is being considered for Ashkenazi Jews (AJ) because 2.5% carry recurrent deleterious mutations and effective cancer prevention exists. This study aimed to provide a qualitative focus on perspectives of individuals, particularly carriers, who were tested through a screening trial. In this trial, the pretest process included only written information.MethodsInterviews were performed with 26 carriers and 10 noncarriers who participated in a BRCA population screening trial for AJ.ResultsAttitudes toward screening were generally positive. The main motivator for testing was knowledge of BRCA status to enable cancer risk reduction. Knowledge of carrier status, although challenging, was thus viewed as health-empowering. The screening paradigm was sensed as increasing awareness and as overcoming access, referral, and familial barriers. Streamlining the pretest process was positively perceived as offering gradual, stepwise knowledge commensurate with test results. Participants were concerned that health systems provide the necessary conceptual and infrastructural framework and that individual autonomy be maintained.ConclusionsBRCA screening in AJ is viewed favorably, even by carriers. Stepwise acquisition of knowledge based on test results was viewed as most relevant to the screening context. Screening program development should account for safeguarding autonomy and providing requisite post-test services.Genet Med advance online publication 01 December 2016     

Haplotype analysis of the 185delAG BRCA1 mutation in ethnically diverse populations

The 185delAG* BRCA1 mutation is encountered primarily in Jewish Ashkenazi and Iraqi individuals, and sporadically in non-Jews. Previous studies estimated that this is a founder mutation in Jewish mutation carriers that arose before the dispersion of Jews in the Diaspora ∼2500 years ago. The aim of this study was to assess the haplotype in ethnically diverse 185delAG* BRCA1 mutation carriers, and to estimate the age at which the mutation arose. Ethnically diverse Jewish and non-Jewish 185delAG*BRCA1 mutation carriers and their relatives were genotyped using 15 microsatellite markers and three SNPs spanning 12.5 MB, encompassing the BRCA1 gene locus. Estimation of mutation age was based on a subset of 11 markers spanning a region of ∼5 MB, using a previously developed algorithm applying the maximum likelihood method. Overall, 188 participants (154 carriers and 34 noncarriers) from 115 families were included: Ashkenazi, Iraq, Kuchin-Indians, Syria, Turkey, Iran, Tunisia, Bulgaria, non-Jewish English, non-Jewish Malaysian, and Hispanics. Haplotype analysis indicated that the 185delAG mutation arose 750–1500 years ago. In Ashkenazim, it is a founder mutation that arose 61 generations ago, and with a small group of founder mutations was introduced into the Hispanic population (conversos) ∼650 years ago, and into the Iraqi–Jewish community ∼450 years ago. The 185delAG mutation in the non-Jewish populations in Malaysia and the UK arose at least twice independently. We conclude that the 185delAG* BRCA1 mutation resides on a common haplotype among Ashkenazi Jews, and arose about 61 generations ago and arose independently at least twice in non-Jews.     

Founder mutations in <Emphasis Type="Italic">BRCA1/2</Emphasis> are not frequent in Canadian Ashkenazi Jewish men with prostate cancer

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.     

Experiences from a pilot program bringing BRCA1/2 genetic screening to the

PurposeThe notion of offering population-based screening to the Ashkenazi Jewish (AJ) population for the BRCA1/2 founder mutations continues to gain support. A program called the BRCAcommunity initiative was designed to identify the benefits and barriers associated with implementing this screening in a clinical setting.MethodsInterested AJ individuals were stratified into high-risk (HR) and low-risk (LR) groups based on self-reported cancer histories. Those at HR were offered traditional genetic counseling/testing; those at LR were offered group genetic counseling and subsidized AJ BRCA founder mutation testing.ResultsDuring the pilot year, 62% of initial registrants and 53% of ultimate study participants were classified into the HR group. Among the 101 HR and 88 LR study participants, 8 and 2 BRCA carriers were identified, respectively. The LR carriers would have been missed by current mechanisms. Survey responses provided insight into the motivations and fears associated with pursuing testing, the efficacy of the initiative design, and challenges that exist on multiple levels, including the community, health-care providers, and insurance coverage.ConclusionAlthough the medical value of identifying presymptomatic BRCA carriers in Ashkenazi Jews is evident, further measures need to be taken before this effort can be accomplished on a large scale.Genet Med advance online publication 13 October 2016     

Common MEFV mutations among Jewish ethnic groups in Israel: High frequency of carrier and phenotype III states and absence of a perceptible biological advantage for the carrier state*

Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent attacks of fever and inflammation of serosal membranes and gradual development of nephropathic amyloidosis. The recent cloning of the FMF gene (MEFV) and identification of disease‐associated mutations in most patients made the direct determination of FMF carrier frequency feasible. The aim of the present study was to investigate the carrier rate of the most common MEFV mutations among different Jewish ethnic groups in Israel. Further, an attempt was made to elucidate the possible biological advantage that the heterozygote state may confer. Three hundred Ashkenazi, 101 Iraqi, and 120 Moroccan Jews were screened for the E148Q, V726A, and M694V mutations (at least two most common mutations per group), with a resulting overall carrier frequency in the respective ethnic group of 14%, 29%, and 21%. No difference in morbidity between Ashkenazi carriers and non‐carriers of MEFV mutations was discerned, although an excess of febrile episodes in carriers of the V726A and in carriers of either V726A or E148Q was evident (P < 0.02 and P < 0.05, respectively). The frequency of subjects with two MEFV mutations but not expressing FMF (phenotype III) was 1:300 in Ashkenazi Jews and 1:25 in Iraqi Jews, exceeding the reported rate of overt FMF in these ethnic groups by 40–240 fold. These results affirm the high carrier rate among the studied Jewish ethnic groups in Israel and suggest that most subjects with FMF mutations are unaffected. © 2001 Wiley‐Liss, Inc.     

Similar prevalence of founder BRCA1 and BRCA2 mutations among Ashkenazi and non-Ashkenazi men with breast cancer: evidence from 261 cases in Israel, 1976-1999

To evaluate the potential contribution of mutations in the BRCA1 and BRCA2 genes to male breast cancer (MBC), we expanded a previous study to screen a total of 261 Israeli men diagnosed with breast carcinoma. A total of 21 BRCA2 6174delT and 8 BRCA1 185delAG mutations were found. Similar frequencies of BRCA1 and BRCA2 mutation carriers were found among Ashkenazi (12.8%) and non-Ashkenazi Jews (9.1%). The combined prevalence of BRCA1/BRCA2 founder mutations among Ashkenazi Jewish men is slightly higher than for women, due to a higher frequency of BRCA2 mutations.     

Parity, oral contraceptives, and the risk of ovarian cancer among carriers and noncarriers of a BRCA1 or BRCA2 mutation

BACKGROUND: Multiparity and the use of oral contraceptives reduce the risk of ovarian cancer, but their effects on this risk in women with a BRCA1 or BRCA2 mutation are unclear. METHODS: We conducted a population-based case-control study of ovarian cancer among Jewish women in Israel. Women were tested for the two founder mutations in BRCA1 and the one founder mutation in BRCA2 that are known to be common among Jews. We estimated the effects of parity and oral-contraceptive use on the risk of ovarian cancer in carriers and noncarriers in separate analyses that included all control women, who did not have ovarian cancer. RESULTS: Of 751 controls who underwent mutation analysis, 13 (1.7 percent) had a BRCA1 or BRCA2 mutation, whereas 244 of 840 women with ovarian cancer (29.0 percent) had a BRCA1 or BRCA2 mutation. Overall, each additional birth and each additional year of use of oral contraceptives were found to lower the risk of ovarian cancer, as expected. Additional births were protective in separate analyses of carriers and noncarriers, but oral-contraceptive use appeared to reduce the risk only in noncarriers; among carriers, the reduction in the odds of ovarian cancer was 12 percent per birth (95 percent confidence interval, 2.3 to 21 percent) and 0.2 percent per year of oral-contraceptive use (-4.9 to 5.0 percent). CONCLUSIONS: The risk of ovarian cancer among carriers of a BRCA1 or BRCA2 mutation decreases with each birth but not with increased duration of use of oral contraceptives. These data suggest that it is premature to use oral contraceptives for the chemoprevention of ovarian cancer in carriers of such mutations.     

Cost-effectiveness of population-based BRCA1/2 testing and ovarian cancer prevention for Ashkenazi Jews: A call for dialogue

PurposeAbout half of unaffected BRCA1/2 carriers have a negative family history, confounding efforts toward presymptomatic carrier identification. Ovarian cancer is preventable for known carriers but is otherwise highly lethal. Cost-effectiveness and gains in life expectancy are important factors in evaluating the desirability of population-based genetic screening, currently the only viable strategy to identify carriers with unrevealing family histories.MethodsCost-utility analysis for a population-based genetic screening program offered to American Ashkenazi Jewish women aged 35–55 years measuring cancer incidence, life expectancy, and cost.ResultsOur model predicts that a genetic screening program would result in 2811 fewer cases of ovarian cancer, with a life expectancy gain of 1.83 quality-adjusted life years among carriers. At a cost of $460 for founder mutation testing, the cost of the program is $8300 (discounted) per year of quality-adjusted life gained.ConclusionIn populations with a high prevalence of BRCA1/2 founder mutations, genetic screening may be cost-effective when compared with recommended public health interventions such as mammographic screening. We advocate the initiation of a dialogue among Jewish stakeholders, genetics professionals, and public health leaders to determine whether a population-based BRCA1/2 genetic screening program should be pursued.     

BRCA1 and sex ratio

Two recent papers suggest distorted sex and transmission ratios associated with BRCA1 mutations. If real, these would provide novel insights into the normal biological function of this gene and have implications for genetic epidemiologic methods used to estimate penetrance. We addressed these observations in two settings: offspring of 283 mutation carriers and 471 mutation negative subjects from BRCA1/2 mutation-positive families with multiple cases of breast and ovarian cancer (NCI families); and relatives of 115 BRCA1/2 mutation carriers from the Washington Ashkenazi Study (WAS). The male:female ratio was below one in both BRCA1 (0.85, 95% CI 0.7-1.1 in NCI families; 0.90, 95% CI 0.6-1.4 in WAS) and BRCA2 families (0.77, 95% CI 0.5-1.3 and 0.80, 95% CI 0.5-1.2, in the NCI and WAS study groups, respectively). None of the sex ratios deviated significantly from one, and there was no significant difference between BRCA1 and BRCA2 families. The reduced sex ratio was due largely to the offspring of males, a distortion that is probably an artifact of ascertainment biases. Among adult daughters without breast or ovarian cancer born to mutation carriers, as expected, fewer than 50% were mutation carriers (39% in BRCA1 families and 44% in BRCA2 families). It is difficult, due to ascertainment biases, to draw firm conclusions regarding sex ratios in studies of a sex-limited phenotype. Nonetheless, these observations do not support the idea that BRCA1 mutation carriers have a lower ratio of male offspring than BRCA2 mutation carriers.     

BRCA genetic testing of individuals from families with low prevalence of cancer: experiences of carriers and implications for population screening

PurposeBRCA genes are associated with hereditary breast and ovarian cancers. Guidelines worldwide currently recommend BRCA genetic testing in asymptomatic individuals only if they belong to “high-risk” families. However, population screening for BRCA1/2 may be the logical next step in populations with a high prevalence of founder mutations, such as Ashkenazi Jews. This study aimed to explore (i) the impact of a positive BRCA genetic test result on individuals who have neither a personal history nor a familial history of cancer and (ii) their attitudes toward the concept of population screening.MethodsSemistructured in-depth interviews were carried out with 14 Ashkenazi Jewish women who were asymptomatic BRCA carriers and who belonged to families with low prevalence of cancer.ResultsThree main findings emerged: (i) having no family history of cancer was a source of optimism but also confusion; (ii) engaging in intensified medical surveillance and undergoing preventive procedures was perceived as health-promoting but also tended to induce a sense of physical and psychological vulnerability; and (iii) there was overall support for BRCA population screening, with some reservations.ConclusionWomen belonging to low-cancer-prevalence families within a “high-risk” ethnic community view BRCA genetic testing positively despite the difficulties entailed, because it allows prevention or early detection of cancer. However, implementing a BRCA population screening program should be carried out with proper pre- and post-testing preparation and support for the individuals undergoing testing.Genet Med advance online publication 5 April 2012     

Tay-Sachs disease and HEXA mutations among Moroccan Jews

Moroccan Jewry (N>750,000) is the only non-Ashkenazi Jewish community in which Tay-Sachs disease (TSD) is not extremely rare. Previous studies among Moroccan Jewish TSD families identified three HEXA mutations. In this study, extended to enzyme-defined and new obilgate TSD carriers, we found four additional mutations. One of them is a novel, IVS5-2(A→G) substitution, resulting in exon skipping, and it was found only among enzyme-defined carriers. The seven HEXA identified mutations among Moroccan Jews are: ΔF^304/305, R170Q, IVS-2(A→G), Y180X, E482K, 1278+TATC, and IVS12+1(G→C). Their respective distribution among 51 unrelated enzyme-defined and obligate carriers is 22:19:6:1:1:1:1. The mutation(s) remain unknown in only three enzyme-defined carriers. Five of the seven Moroccan mutations, including the three most common ones, were not found among Ashkenazi Jews. Compared with the much larger and relatively homogeneous Ashkenazi population, the finding among Moroccan Jews probably reflects their much longer history. Hum Mutat 10:295–300, 1997. © 1997 Wiley-Liss, Inc.     

Breast and ovarian cancer risks to carriers of the BRCA1 5382insC and 185delAG and BRCA2 6174delT mutations: a combined analysis of 22 population based studies

A recent report estimated the breast cancer risks in carriers of the three Ashkenazi founder mutations to be higher than previously published estimates derived from population based studies. In an attempt to confirm this, the breast and ovarian cancer risks associated with the three Ashkenazi founder mutations were estimated using families included in a previous meta-analysis of populatrion based studies. The estimated breast cancer risks for each of the founder BRCA1 and BRCA2 mutations were similar to the corresponding estimates based on all BRCA1 or BRCA2 mutations in the meta-analysis. These estimates appear to be consistent with the observed prevalence of the mutations in the Ashkenazi Jewish population.     

BRCA1/2 mutations and FMR1 alleles are randomly distributed: a case control study

BRCA mutation carriers were reported to display a skewed distribution of FMR1 genotypes, predominantly within the low normal range (CGG repeat number <26). This observation led to the interpretation that BRCA1/2 mutations are embryo-lethal, unless rescued by ‘low FMR1 alleles''. We undertook to re-explore the distribution of FMR1 alleles subdivided into low, normal and high (<26, 26–34, and >34 CGG repeats, respectively) subgenotypes, on a cohort of 125 Ashkenazi women, carriers of a BRCA1/2 founder mutation. Ashkenazi healthy females (n=368), tested in the frame of the Israeli screening population program, served as controls. BRCA1/2 carriers and controls demonstrated a comparable and non-skewed FMR1 subgenotype distribution. Taken together, using a homogeneous ethnic group of Ashkenazi BRCA1/2 mutation carriers, we could not confirm the reported association between FMR1 low genotypes and BRCA1/2 mutations. The notion that BRCA1/2 mutations are embryo-lethal unless rescued by the low FMR1 subgenotypes is hereby refuted.     

Common MEFV mutations among Jewish ethnic groups in Israel: high frequency of carrier and phenotype III states and absence of a perceptible biological advantage for the carrier state

Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent attacks of fever and inflammation of serosal membranes and gradual development of nephropathic amyloidosis. The recent cloning of the FMF gene (MEFV) and identification of disease-associated mutations in most patients made the direct determination of FMF carrier frequency feasible. The aim of the present study was to investigate the carrier rate of the most common MEFV mutations among different Jewish ethnic groups in Israel. Further, an attempt was made to elucidate the possible biological advantage that the heterozygote state may confer. Three hundred Ashkenazi, 101 Iraqi, and 120 Moroccan Jews were screened for the E148Q, V726A, and M694V mutations (at least two most common mutations per group), with a resulting overall carrier frequency in the respective ethnic group of 14%, 29%, and 21%. No difference in morbidity between Ashkenazi carriers and non-carriers of MEFV mutations was discerned, although an excess of febrile episodes in carriers of the V726A and in carriers of either V726A or E148Q was evident (P < 0.02 and P < 0.05, respectively). The frequency of subjects with two MEFV mutations but not expressing FMF (phenotype III) was 1:300 in Ashkenazi Jews and 1:25 in Iraqi Jews, exceeding the reported rate of overt FMF in these ethnic groups by 40-240 fold. These results affirm the high carrier rate among the studied Jewish ethnic groups in Israel and suggest that most subjects with FMF mutations are unaffected.     

Carrier screening of RTEL1 mutations in the Ashkenazi Jewish population

Hoyeraal–Hreidarsson syndrome (HH) is a clinically severe variant of dyskeratosis congenita (DC), characterized by cerebellar hypoplasia, microcephaly, intrauterine growth retardation, and severe immunodeficiency in addition to features of DC. Germline mutations in the RTEL1 gene have recently been identified as causative of HH. In this study, the carrier frequency for five RTEL1 mutations that occurred in individuals of Ashkenazi Jewish descent was investigated in order to advise on including them in existing clinical mutation panels for this population. Our screening showed that the carrier frequency for c.3791G>A (p.R1264H) was higher than expected, 1% in the Ashkenazi Orthodox and 0.45% in the general Ashkenazi Jewish population. Haplotype analyses suggested the presence of a common founder. We recommend that the c.3791G>A RTEL1 mutation be considered for inclusion in carrier screening panels in the Ashkenazi population.     

Sleep disturbances in asymptomatic BRCA1/2 mutation carriers: women at high risk for breast–ovarian cancer

This study investigated the association between positive genetic diagnosis for BRCA1/2 mutations and sleep quality in Ashkenazi asymptomatic women. Seventy‐three women, including 17 asymptomatic BRCA1/2 carriers and 20 non‐carriers from the oncogenetic clinic, and 36 community controls, participated in a cross‐sectional design. Women completed sociodemographic, clinical, general psychological distress, cancer‐related worry (CRW), fatigue and sleep questionnaires in their homes, and wore actigraphs for 5–7 nights. Impaired global subjective sleep quality was demonstrated in BRCA1/2 carriers compared to non‐carriers and controls [mean Pittsburgh sleep quality index (PSQI) total scores 7.29 ± 4.34; 3.94 ± 2.49; 4.21 ± 2.80, respectively, P = 0.021] and poor sleep quality (PSQI total score >5) was significantly higher in carriers (53%) compared to non‐carriers (20%) and controls (28%, P = 0.03). Based on actigraphic measures, sleep latency tended to be longer in carriers compared to counterparts, albeit not significantly. Increased sleep disturbance was related significantly to increased fatigue in the entire sample and in the control group; to psychological distress in the entire sample and in non‐carriers; and to CRW in the entire sample. In carriers, sleep disturbance was related strongly but non‐significantly to fatigue, psychological distress and CRW. Fatigue and carrier status were significant predictors of sleep quality, accounting for 15.7% of the variance. In conclusion, asymptomatic BRCA1/2 carriers experience poor sleep quality compared to non‐carriers and controls. Our study design is unique in that it offers insight regarding the nature of being an asymptomatic carrier, and affords the opportunity to examine factors that may contribute to the development of insomnia in women at risk for breast–ovarian cancer.     

Differences in BRCA counseling and testing practices based on ordering provider type

PurposeThe purpose of this study was to assess potential differences in genetic counseling services delivered by board-certified genetic health-care providers versus non–genetic health-care providers. We evaluated (i) patient recall and content of pretest genetic counseling for hereditary breast and ovarian cancer and (ii) whether full BRCA1 and 2 gene sequencing was performed when less expensive single-site or Ashkenazi Jewish founder mutation testing may have been sufficient.MethodsParticipants completed a questionnaire and provided BRCA test reports that included testing provider and type of test. Chi-square tests and logistic regression were used for analysis.ResultsOf 473 participants, >90% were white, female, and BRCA mutation carriers. Of the 276 (58%) with genetic health-care provider involvement, 97% recalled a pretest discussion as compared with 59% of those without genetic health-care provider involvement (P < 0.001). Among the subgroup who recalled a pretest discussion (n = 385), those with genetic health-care provider involvement indicated higher adherence to eight recognized genetic counseling elements, four of which were statistically significant. Furthermore, involvement of a genetic health-care provider halved the likelihood that comprehensive BRCA testing was ordered among the 266 for whom single-site or multisite-3 testing may have been sufficient (P = 0.02).ConclusionOur results suggest that genetic health-care provider involvement is associated with adherence to nationally recommended genetic counseling practices and could potentially reduce costs of BRCA genetic testing.Genet Med advance online publication 12 June 2014     

Risk factors for detecting germline BRCA1 and BRCA2 founder mutations in Ashkenazi Jewish women with breast or ovarian cancer

We ascertained 184 Ashkenazi Jewish women with breast/ovarian cancer (171 breast and 13 ovarian cancers, two of the former also had ovarian cancer) in a self-referral study. They were tested for germline founder mutations in BRCA1 (185delAG, 5382insC, 188del11) and BRCA2 (6174delT). Personal/family histories were correlated with mutation status. Logistic regression was used to develop a model to predict those breast cancer cases likely to be germline BRCA1/BRCA2 mutation carriers in this population. The most important factors were age at diagnosis, personal/family history of ovarian cancer, or breast cancer diagnosed before 60 years in a first degree relative. A total of 15.8% of breast cancer cases, one of 13 ovarian cancer cases (7.7%), and both cases with ovarian and breast cancer carried one of the founder mutations. Age at diagnosis in carriers (44.6 years) was significantly lower than in non-carriers (52.1 years) (p<0.001), and was slightly lower in BRCA1 than BRCA2 carriers. Thirty three percent of carriers had no family history of breast or ovarian cancer in first or second degree relatives. Conversely, 12% of non-mutation carriers had strong family histories, with both a first and a second degree relative diagnosed with breast or ovarian cancer. The predicted values from the logistic model can be used to define criteria for identifying Ashkenazi Jewish women with breast cancer who are at high risk of carrying BRCA1 and BRCA2 mutations. The following criteria would identify those at approximately 10% risk: (1) breast cancer <50 years, (2) breast cancer <60 years with a first degree relative with breast cancer <60 years, or (3) breast cancer <70 years and a first or second degree relative with ovarian cancer.     

Haplotype analysis of a BRCA1: 185delAG mutation in a Chilean family supports its Ashkenazi origins

At least 25% of Ashkenazi Jewish families with two or more cases of premenopausal breast cancers are attributable to one of three founder mutations in BRCA1 or BRCA2. As these three founder mutations are common in the Ashkenazi Jewish population ( approximately 2.5%) and can easily be tested for in a multiplex assay, establishing ethnicity can expedite genetic testing. It is not always possible, however, to conclusively establish ethnicity before offering testing. We report here the occurrence of a founder Ashkenazi Jewish BRCA1 mutation, 185delAG (also known as 187delAG), in a non-Jewish Chilean family with no reported Jewish ancestry. The linked haplotype present in this family was identical to that identified in the Ashkenazi Jewish population. This case report not only illustrates the problem of the definition of ethnicity but also points to the possibility of further studies of the frequency of founder Ashkenazi Jewish mutations in populations not generally considered to be of Ashkenazi Jewish origin.