Length of FMR1 repeat alleles within the normal range does not substantially affect the risk of early menopause.

STUDY QUESTION: Is the length of FMR1 repeat alleles within the normal range associated with the risk of early menopause? SUMMARY ANSWER: The length of repeat alleles within the normal range does not substantially affect risk of early menopause. WHAT IS KNOWN ALREADY: There is a strong, well-established relationship between length of premutation FMR1 alleles and age at menopause, suggesting that this relationship could continue into the normal range. Within the normal range, there is conflicting evidence; differences in ovarian reserve have been identified with FMR1 repeat allele length, but a recent population-based study did not find any association with age at menopause as a quantitative trait. STUDY DESIGN, SIZE, DURATION: We analysed cross-sectional baseline survey data collected at recruitment from 2004 to 2010 from a population-based, prospective epidemiological cohort study of >110 000 women to investigate whether repeat allele length was associated with early menopause. PARTICIPANTS/MATERIALS, SETTING, METHOD: We included 4333 women from the Breakthrough Generations Study (BGS), of whom 2118 were early menopause cases (menopause under 46 years) and 2215 were controls. We analysed the relationship between length of FMR1 alleles and early menopause using logistic regression with allele length as continuous and categorical variables. We also conducted analyses with the outcome age at menopause as a quantitative trait as well as appropriate sensitivity and exploratory analyses. MAIN RESULTS AND THE ROLE OF CHANCE: There was no association of the shorter or longer FMR1 allele or their combined genotype with the clinically relevant end point of early menopause in our main analysis. Likewise, there were no associations with age at menopause as a quantitative trait in our secondary analysis. LIMITATIONS, REASONS FOR CAUTION: Women with homozygous alleles in the normal range may have undetected FMR1 premutation alleles, although there was no evidence to suggest this. We estimate minor dilution of risk of early menopause from the likely inclusion of some women with menopause at over 45 years in the early menopause cases due to age-rounding bias in self-reports. WIDER IMPLICATIONS OF THE FINDINGS: There is no robust evidence in this large study that variation within the normal range of FMR1 repeat alleles influences timing of menopause in the general population, which contradicts findings from some earlier, mainly smaller studies. The FMR1 CGG repeat polymorphism in the normal range is unlikely to contribute to genetic susceptibility to early menopause. STUDY FUNDING/COMPETING INTERESTS: We thank Breast Cancer Now and The Institute of Cancer Research for funding the BGS. The Institute of Cancer Research acknowledges NHS funding to the NIHR Biomedical Research Centre. The study was funded by the Wellcome Trust (grant number 085943). There are no competing interests. TRIAL REGISTRATION NUMBER: Not applicable.

Population-based estimates of the prevalence of FMR1 expansion mutations in women with early menopause and primary ovarian insufficiency.

PURPOSE: Primary ovarian insufficiency before the age of 40 years affects 1% of the female population and is characterized by permanent cessation of menstruation. Genetic causes include FMR1 expansion mutations. Previous studies have estimated mutation prevalence in clinical referrals for primary ovarian insufficiency, but these are likely to be biased as compared with cases in the general population. The prevalence of FMR1 expansion mutations in early menopause (between the ages of 40 and 45 years) has not been published. METHODS: We studied FMR1 CGG repeat number in more than 2,000 women from the Breakthrough Generations Study who underwent menopause before the age of 46 years. We determined the prevalence of premutation (55-200 CGG repeats) and intermediate (45-54 CGG repeats) alleles in women with primary ovarian insufficiency (n = 254) and early menopause (n = 1,881). RESULTS: The prevalence of the premutation was 2.0% in primary ovarian insufficiency, 0.7% in early menopause, and 0.4% in controls, corresponding to odds ratios of 5.4 (95% confidence interval = 1.7-17.4; P = 0.004) for primary ovarian insufficiency and 2.0 (95% confidence interval = 0.8-5.1; P = 0.12) for early menopause. Combining primary ovarian insufficiency and early menopause gave an odds ratio of 2.4 (95% confidence interval = 1.02-5.8; P = 0.04). Intermediate alleles were not significant risk factors for either early menopause or primary ovarian insufficiency. CONCLUSION: FMR1 premutations are not as prevalent in women with ovarian insufficiency as previous estimates have suggested, but they still represent a substantial cause of primary ovarian insufficiency and early menopause.

Common genetic variants are significant risk factors for early menopause: results from the Breakthrough Generations Study.

Women become infertile approximately 10 years before menopause, and as more women delay childbirth into their 30s, the number of women who experience infertility is likely to increase. Tests that predict the timing of menopause would allow women to make informed reproductive decisions. Current predictors are only effective just prior to menopause, and there are no long-range indicators. Age at menopause and early menopause (EM) are highly heritable, suggesting a genetic aetiology. Recent genome-wide scans have identified four loci associated with variation in the age of normal menopause (40-60 years). We aimed to determine whether theses loci are also risk factors for EM. We tested the four menopause-associated genetic variants in a cohort of approximately 2000 women with menopause≤45 years from the Breakthrough Generations Study (BGS). All four variants significantly increased the odds of having EM. Comparing the 4.5% of individuals with the lowest number of risk alleles (two or three) with the 3.0% with the highest number (eight risk alleles), the odds ratio was 4.1 (95% CI 2.4-7.1, P=4.0×10(-7)). In combination, the four variants discriminated EM cases with a receiver operator characteristic area under the curve of 0.6. Four common genetic variants identified by genome-wide association studies, had a significant impact on the odds of having EM in an independent cohort from the BGS. The discriminative power is still limited, but as more variants are discovered they may be useful for predicting reproductive lifespan.

Intermediate sized CGG repeats are not a common cause of idiopathic premature ovarian failure.

BACKGROUND: It is recognized that FMR1 premutation expansions are associated with premature ovarian failure (POF), but the role of smaller repeats at the boundary of premutation and normal is less clear. METHODS: We have therefore investigated the incidence of these intermediate sized FMR1 CGG repeats (35-58 repeats) in a series of 366 women ascertained because of menopause before the age of 40. RESULTS: We found no significant difference in the incidence of intermediates in cases compared with controls. Thus, we were unable to replicate previous studies showing a positive association, despite a significantly larger sample size. CONCLUSIONS: We therefore conclude that intermediate sized FMR1 CGG repeat alleles should not be considered a high-risk factor for POF based on current evidence.

CCAAT/enhancer binding protein alpha, beta and delta gene variants: associations with obesity related phenotypes in the Leeds Family Study.

OBJECTIVE: To identify novel polymorphisms in the genes encoding the transcription factors CCAAT/enhancer binding protein alpha, beta and delta ( CEBPA, CEBPB, CEBPD) and investigate associations between polymorphisms and obesity-related phenotypes. METHODS: Denaturing high-performance liquid chromatography (HPLC) was used to screen for novel gene variants and polymorphisms were genotyped in stored DNA from participants of the Leeds Family Study (537 subjects from 89 families). Genotype and haplotype analyses were carried out in STATA and PBAT, respectively. RESULTS: Twenty-five polymorphisms were identified; 11 in CEBPA, 12 in CEBPB and 2 in CEBPD. Several allelic variants were associated at a nominal 5% level with waist-to-hip ratio (-919G>A in CEBPA, -412G>T and 646C>T in CEBPB), leptin (1558G>A in CEBPA, -1051A>G and 1383T>- in CEBPB) and adiponectin (1382G>T and 1903G>T in CEBPB). Effects of CEBPA and CEBPB allelic variants were independent, but variants within each gene were in linkage disequilibrium. Several associations were observed between other obesity-related traits and allelic variants in CEBPA and CEBPB, but not CEBPD. CONCLUSION: These findings suggest that common allelic variants in CEBPA and CEBPB could influence abdominal obesity and related metabolic abnormalities associated with type 2 diabetes and cardiovascular disease in healthy White Northern European families, although results require independent confirmation.

Genetic variation at the interleukin-1 locus is a determinant of changes in soluble endothelial factors in patients with acute coronary syndromes.

Acute coronary syndromes (ACSs) are associated with both systemic inflammatory activation and endothelial cell activation, and both of these are linked to patient outcome. Genetic variation at the interleukin-1 (IL-1) locus influences the clinical patterns of inflammatory disease. We therefore examined the association between IL-1 gene polymorphisms and levels of systemic inflammatory activation markers [C-reactive protein (CRP) and IL-1 receptor antagonist (IL-1ra)] and of soluble endothelial activation markers [von Willebrand factor (vWF) and E-selectin], in a cohort of 63 patients presenting with non-ST-elevation ACS. The IL-1 locus did not significantly influence any of the markers studied at 24 h after presentation. Associations of IL-1 polymorphisms with the changes (Delta) in CRP, IL-1ra, E-selectin and vWF levels between 24 and 48 h were examined in later studies. Delta CRP and Delta IL-1ra showed no significant association with any of the polymorphisms studied. There was a strong association between carriage of the rare allele (allele 2) of the intron 2 variable number of tandem repeats polymorphism of IL-1RN (designated IL-1RN*2) and Delta E-selectin levels: [carriage of *2, 3.03 ng/ml [95% confidence interval (CI) 6.26 to 1.51 ng/ml]; non-carriage of *2, 0.12 ng/ml (95% CI 1.07 to -1.76 ng/ml); P=0.0016], and also between carriage of IL-1RN*2 and Delta vWF levels [carriage of *2, 0.78 i.u./ml (95% CI 0.96 to 0.44 i.u./ml); non-carriage of *2, 0.1 i.u./ml (95% CI 0.19 to -0.1 i.u./ml); P=0.0003]. A composite analysis consisting of carriage of IL-1RN*2 and the genotype at position -511 in the IL-1B gene suggests the existence of haplotypes that influence Delta vWF and Delta E-selectin in patients with ACS. Carriage of IL-1RN*2 was also associated with a 2-fold increased likelihood of a troponin-positive status compared with non-carriage (P=0.0385). These data indicate that, in the setting of non-ST-elevation ACS, genetic variation at the IL-1 gene locus contributes to the changes in soluble markers of endothelial inflammation.