Background: It is not understood whether long-term good health is promoted by the absence of disease risk variants, the presence of protective variants, or both. We characterized the exomes of two exceptionally healthy centenarian brothers aged 106 and 109 years who had never been diagnosed with cancer, cardiovascular disease, diabetes, Alzheimer's disease, or major pulmonary disease. Objective: The aim of this study was to gain insight into whether exceptional health and longevity are a result of carrying fewer disease-associated variants than typical individuals. Methods: We compared the number of disease-associated alleles, and the proportion of alleles predicted to be functionally damaging, between the centenarian brothers and published population data. Mitochondrial sequence reads were extracted from the exome data in order to analyze mitochondrial variants. Results: The brothers carry a similar number of common disease-associated variants and predicted damaging variants compared to reference groups. They did not carry any high-penetrance clinically actionable variants. They carry mitochondrial haplogroup T, and one brother has a single heteroplasmic variant. Conclusion: Although our small sample size does not allow for definitive conclusions, a healthy aging and longevity phenotype is not necessarily due to a decreased burden of common disease-associated variants. Instead, it may be rare ‘positive' variants that play a role in this desirable phenotype.

Due to the critical role of the H2AX histone variant in double-strand break repair, genetic variants in the H2AX gene, H2AFX, may influence cancer susceptibility. Genetic association studies have correlated H2AFX upstream variants with cancer risk; however it is unclear if any are causal. H2AFX has at least two alternate transcripts that encode the same reading frame; a short 0.6kb transcript that lacks an intron or poly-A tail and is predicted to be highly expressed during the replication stage of the cell cycle, and a long 1.6kb poly-A tailed transcript that is expressed in a replication-independent manner. To examine the functional impact of the rs643788, rs8551, rs7759, and rs2509049 upstream variants, we characterized their influence on gene expression, cell survival after DNA assault, and transcription factor binding. Analysis of allelic imbalance using quantitative sequencing of cDNA from lymphoblast cell lines did not reveal any difference in expression of the 1.6kb polyadenylated transcript between the common H2AFX upstream haplotypes. We did, however, identify a previously unreported 197 base pair intron in the H2AFX 3'untranslated region that appears to be present regardless of haplotype. Assessment of cell survival after irradiation treatment did not show any difference in survival between cell lines of different haplotypes. Gel shift assays revealed that the rs643788 C allele disrupts YY1 transcription factor binding and the rs2509049 C allele binds more strongly to a protein complex than does the rs2509049 T allele. Though we did not identify any differences in expression or survival between haplotypes, differential protein binding at two of the polymorphisms suggests further functional analyses may reveal a role for these variants in influencing gene expression at specific points of the cell cycle or in specific tissues.

H2AFX encodes a histone variant involved in signaling sites of DNA damage and recruiting repair factors. Genetic variants in H2AFX may influence risk of non-Hodgkin lymphoma (NHL), a heterogeneous group of lymphoid tumors that are characterized by chromosomal translocations. We previously reported that rs2509049, a common variant in the promoter of H2AFX, was associated with risk for NHL in the British Columbia population. Here we report results for 13 single nucleotide polymorphisms (SNPs) in 100 Kb surrounding H2AFX in an expanded collection of 568 NHL cases and 547 controls. After correction for multiple testing, significant associations were present for mantle cell lymphoma (p=0.007 for rs604714) and all B-cell lymphomas (p=0.046 for rs2509049). Strong linkage disequilibrium in the 5 Kb upstream of H2AFX limited the ability to determine which specific SNP (rs2509049, rs7759, rs8551, rs643788, rs604714, or rs603826), if any, was responsible. There was a significant interaction between sex and rs2509049 in the all B-cell lymphomas group (p=0.002); a sex-stratified analysis revealed that the association was confined to females (p=0.001). Neither the overall nor the female-specific association with rs2509049 was replicated in any of four independent NHL sample sets. Meta-analysis of all five study populations (3,882 B-cell NHL cases and 3,718 controls) supported a weak association with B-cell lymphoma (OR=0.92, 95% CI=0.86-0.99, p=0.034), although this association was not significant after exclusion of the British Columbia data. Further research into the potential sex-specificity of the H2AFX-NHL association may identify a subset of NHL cases that are influenced by genotype at this locus.

To the editor: The t(14;18) translocation is found in nearly 90% of follicular lymphomas (FLs), but it is also known to be present in low numbers (fewer than 1 per 10 000 cells) in peripheral blood lymphocytes of healthy individuals.[1][1],[2][2] These cells possess hallmarks of premalignant cells

ObjectiveFemale fertility declines with age; however, women are increasingly delaying childbearing until later in their reproductive years. One of the factors that may contribute to this trend is a general lack of knowledge about the decline in fertility with age.DesignSelf-report survey. Questions pertained to participant demographics and childbearing intentions, and knowledge of the decline in fertility and increased risk of pregnancy loss with age.SettingThe University of British Columbia in Vancouver, British Columbia, Canada.PatientsFemale undergraduate students (N = 360).Intervention(s)None.Main Outcome Measure(s)Knowledge of fertility over the life span, predictors of age of intended childbearing.Result(s)Although most women were aware that fertility declines with age, they significantly overestimated the chance of pregnancy at all ages and were not conscious of the steep rate of fertility decline. Surprisingly, women overestimated the chance of pregnancy loss at all ages, but did not generally identify a woman's age as the strongest risk factor for miscarriage.Conclusion(s)Education regarding the rate at which reproductive capacity declines with age is necessary to avoid unintended childlessness among female academics and professionals.

BACKGROUND:Recurrent miscarriage affects 1-2% of couples trying to conceive, and is idiopathic in nearly half. Female fertility is controlled by the hypothalamus-pituitary-ovarian (HPO) axis and we hypothesize that genetic polymorphisms affecting the function of genes involved in regulating the HPO axis will be associated with recurrent miscarriage.METHODS:Whole peripheral blood DNA from 227 women with recurrent miscarriage and 130 control women was obtained for this study. Using the Sequenom iPlex assay for fragment analysis, 31 single-nucleotide polymorphisms (SNPs) and 4 short tandem repeat (STR) polymorphisms in 20 candidate genes were evaluated for genetic association with recurrent miscarriage.RESULTS:Several candidate associations were identified with an uncorrected P-value of 0.05. Genotype distribution at an SNP (rs37389) in the prolactin receptor gene (P = 0.03), and allele distributions at an SNP (rs41423247) in the glucocorticoid receptor gene (P = 0.04) and an STR polymorphism in the estrogen receptor β gene (P = 0.03) were associated with recurrent miscarriage. The T allele of an SNP (rs2033962) within the activin receptor type 1 gene (ACVR1) was associated with increased number of miscarriages in an additive manner (P = 0.02). These candidate associations were not statistically significant after correcting for multiple analyses.CONCLUSIONS:Candidate associations were identified between recurrent miscarriage and genetic variation within ESR2, PRLR, GCCR and ACVR1 genes. Independent confirmation of these results is needed, as limitations of this study include the heterogeneous etiology of recurrent miscarriage, limited sample size, partial availability of reproductive history of the control group and investigation of only a subset of the genetic variation within each gene.

Rate of reproductive aging may be related to rate of biological aging. Thus, indicators of aging, such as short telomere length, may be more frequent in women with a history suggestive of premature reproductive senescence.Telomere-specific quantitative PCR was used to assess telomere length in two groups of women with evidence of reproductive aging: (i) patients with idiopathic premature ovarian failure (POF, N = 34) and (ii) women with a history of recurrent miscarriage (RM, N = 95); and two control groups: (1) women from the general population (C1, N = 108) and (2) women who had a healthy pregnancy after 37 years of age (C2, N = 46).The RM group had shorter age-adjusted mean telomere length than controls (8.46 versus 8.92 kb in C1 and 9.11 kb in C2, P = 0.0004 and P = 0.02 for C1 and C2, respectively), although short telomeres were not confined to subsets of this group known to have experienced single or multiple trisomic pregnancies. Although sample size is limited, mean telomere length in the POF group was significantly longer than that in C1 (9.58 versus 8.92 kb, P = 0.01).Women experiencing RM may have shorter telomeres as a consequence of a more rapid rate of aging, or as a reflection of an increased level of cellular stress. Longer telomere length in the POF group may be explained by abnormal hormone exposure, slow cell division rates or autoimmunity in these women. Despite small sample sizes, these results suggest that different manifestations of reproductive aging are likely influenced by distinct physiological factors.

Previous studies have suggested an association between rates of biological and reproductive aging. Short telomere length is a marker for cellular aging and may occur more frequently in women with poor oocyte quality and a history of premature reproductive senescence. Telomere length, however, has been both positively and negatively associated with different measures of reproductive aging in a number of studies. In the present study, the investigators tested the hypothesis that women with a history of premature reproductive aging have a shorter average telomere length than women without such a history. Telomere length in peripheral blood leukocytes was measured in 2 groups of women with evidence of premature reproductive aging: Group 1 (n = 34) was comprised of women with idiopathic premature ovarian failure (POF) who experienced menopause before 40 years of age and group 2 (it = 95) contained women with a history of recurrent miscarriage (RM). The 2 control groups were healthy women of reproductive age from the general Population (C1, n = 108) and women who had had a healthy pregnancy after 37 years of age (C2, n = 46). Telomere length was measured using telomere-specific quantitative PCR.The age-adjusted mean telomere length was shorter among women in the RM group than among those in both control groups (8.46 kb for RM vs. 8.92 kb for C1, [P = 0.0004] and 9.11 kb for C2, [P = 0.02]), respectively. However, this effect was not specifically confined to women known to have experienced trisomic pregnancies. Contrary to expectation, women in the POF group did not have a shorter age-adjusted mean telomere length than those in the controls: Telomere length in POF women was longer compared to C1 (9.58 vs. 8.92 kb, P = 0.01) and not significantly different than C2.These findings suggest that both the opposing association of RM and POF with telomere length, and lack of an association of trisomic pregnancy-as manifestations of different types of reproductive aging-may result from unique physiological factors. The results require confirmation in studies with larger and more defined patient populations.

OBJECTIVE:To assess the role of hormone receptor/binding protein variants in genetic predisposition to premature ovarian failure (POF).DESIGN:Case-control study.SETTING:Academic.PATIENT(S):Fifty-five POF patients, 107 control women from the general population, and 27 control women who had proven fertility after age 37.INTERVENTION(S):None.MAIN OUTCOME MEASURE(S):Allele distributions in cases and controls were assessed for genetic association.RESULT(S):Allele distributions of polymorphisms at the androgen receptor (AR) gene, estrogen receptor beta (ESR2) gene, sex hormone-binding globulin (SHBG) gene, and FSH receptor (FSHR) gene did not differ between patients and controls. At a repeat in a promoter of the estrogen receptor alpha(ESR1) gene, POF patients had fewer (<18) short repeat alleles than did controls (P=.004 vs. combined controls). Genotypes consisting of two short alleles were found in 36.4% of control women but only 5.5% of POF patients (P<.0001 vs. combined controls). The ESR1 repeat may confer risk for POF in a simple dominant manner in which carriers of a long repeat have a relative risk of 9.7 (95% CI = 2.6 - 35.6).CONCLUSION(S):Polymorphisms at the ESR1 gene are associated with POF in this patient population, while those in AR, ESR2, SHBG, and FSHR showed no association. Further studies are necessary to confirm these findings in larger patient samples and to identify the specific predisposing lesion.

Premature ovarian failure (POF) is the occurrence of menopause before the age of 40, and may present with either primary or secondary amenorrhea. Numerous cases of POF in women with X-chromosome deletions or translocations have been reported; thus, it is possible that smaller rearrangements undetectable by conventional cytogenetics may contribute to POF in some patients. In females with an abnormal X chromosome, cells with inactivation of the normal X may be selected against, causing skewed X-chromosome inactivation (XCI). We therefore assessed XCI by methylation sensitive restriction digestion and PCR amplification at the androgen receptor (AR) locus, in 4 primary and 55 secondary POF patients and 109 control women. In samples heterozygous at AR and therefore informative for the skewing assay, the frequency of skewed XCI among the women with secondary amenorrhea was identical to that in control women, with 4 out of 48 (8.3%) secondary ovarian failure patients and 8 out of 97 (8.2%) control women having > or =90% skewing. Notably, all three primary amenorrhea patients that were informative at AR had skewed XCI > or =90% (P = 0.001 vs. control women; Fisher's exact test). To investigate whether X-chromosome copy number alterations were responsible, DNA from selected patients with skewed XCI was examined by high resolution DNA microarray, however no potential regions of DNA addition or deletion were confirmed by FISH or PCR. X-chromosome abnormalities undetectable by array, or reduced follicular pool due to an early trisomic rescue event, may explain the skewed XCI observed in POF patients presenting with primary amenorrhea.

Premature ovarian failure (POF) is the occurrence of menopause before the age of 40 and affects 1% of the female population. Whereas the etiology of POF is largely unexplained, FMR1 premutation carriers are known to be at increased risk of POF compared with the general population. The FMR1 premutation alleles have 55–200 copies of a CGG repeat in the 5′ untranslated region of the FMR1 gene. However, functional effects on gene expression may occur even for repeat sizes in what has been considered the “normal” range. To evaluate the role of the FMR1 repeat in POF, repeat sizes were examined in 53 women with idiopathic POF, 161 control women from the general population, and 21 women with proven fertility at an advanced maternal age. A significant increase in the number of FMR1 alleles between and including 35 and 54 CGG repeats was found in the POF patient population; 15 of 106 (14.2%) POF alleles were between and including 35 and 54 repeats, whereas only 21 of 322 (6.5%) alleles in the general population (P=0.02) and 2 of 42 (4.8%) alleles from women with proven late fertility (P=0.09) were of this size (P=0.01 versus combined controls). The effect was also significant for comparisons of genotype repeat size (repeat size weighted by the relative activity of the two FMR1 alleles) and biallelic mean (average size of the two alleles). These results are clinically relevant and suggest that the FMR1 gene plays a more significant role in the incidence of POF than has previously been thought.

Recently, we reported that skewed X chromosome inactivation (XCI) was more common in women who had experienced a trisomic pregnancy as compared to control women. Rather than an overall shift in the distribution of skewing there appears to only be an excess of extreme (= 95%) skewing. Further analysis of our data reveals that the increase in skewed XCI is dependent on which chromosome is involved in the trisomy and how many trisomies the woman has experienced, although sample sizes in each group are small. In this review we discuss limitations of the commonly used assays of XCI, which use measurements of DNA methylation to infer skewing patterns, and review the data based on current knowledge of the causes of XCI skewing. Gonadal mosaicism, premature aging, loss of methylation at some CpGs, and X-linked mutations can all be considered as potential mechanisms explaining both increased risk of trisomy and skewed XCI. While further research is needed to evaluate the role of each of these, the association of trisomy with apparent skewed XCI in the mother offers new opportunities to clarify the risk factors for and causes of the high incidence of aneuploidy in human females.