Genome-wide linkage analyses of systolic blood pressure using highly discordant siblings

BACKGROUND

Elevated blood pressure is a risk factor for cardiovascular, cerebrovascular, and renal diseases. Complex mechanisms of blood pressure regulation pose a challenge to identifying genetic factors that influence interindividual blood pressure variation in the population at large.

METHODS AND RESULTS

We performed a genome-wide linkage analysis of systolic blood pressure in humans using an efficient, highly discordant, full-sibling design. We identified 4 regions of the human genome that show statistical significant linkage to genes that influence interindividual systolic blood pressure variation (2p22.1 to 2p21, 5q33.3 to 5q34, 6q23.1 to 6q24.1, and 15q25.1 to 15q26.1). These regions contain a number of candidate genes that are involved in physiological mechanisms of blood pressure regulation.

CONCLUSIONS

These results provide both novel information about genome regions in humans that influence interindividual blood pressure variation and a basis for identifying the contributing genes. Identification of the functional mutations in these genes may uncover novel mechanisms for blood pressure regulation and suggest new therapies and prevention strategies.

Positional genomic analysis identifies the beta(2)-adrenergic receptor gene as a susceptibility locus for human hypertension

BACKGROUND

-After genome-wide linkage analyses of blood pressure levels, we resequenced 5 positional candidate genes in a linkage region on chromosome 5 and genotyped selected variants in several family samples from Rochester, Minn.

METHODS AND RESULTS

In a sample of 55 pedigrees containing >/=1 sibling-pair(s) discordant for systolic blood pressure, polymorphisms within the beta(2)-adrenergic receptor gene (Arg16Gly, P=0.009) and the glutathione peroxidase 3 gene (-302G-->A, P=0.037; -623A-->C, P=0.013) were significantly related to blood pressure levels. In a second sample of 298 nuclear families (n=1283 individuals), the Arg16Gly polymorphism was significantly associated with diastolic blood pressure in family-based analyses (P=0.016) and with both diastolic (P=0.009) and mean arterial blood pressure (P=0.038) in analyses of the parental generation only. Neither polymorphism in the glutathione peroxidase 3 gene was associated with blood pressure levels in this sample. An additional 291 families (n=1240 individuals) were added to the nuclear family sample, and the Gln27Glu polymorphism in the beta(2)-adrenergic receptor gene was significantly associated with both systolic (P=0.034) and mean arterial blood pressure (P=0.035) in the parental generation of the combined 589 families. The frequencies of both the Gly16 and Glu27 alleles were higher in hypertensives than in normotensives (0.649 versus 0.604 and 0.490 versus 0.429, respectively), and the odds ratio for the occurrence of hypertension was 1.80 (95% confidence interval, 1.08 to 3.00; P=0. 023) for the Glu27 allele.

CONCLUSIONS

The results of this study provide support for further detailed investigations of the mechanistic pathways by which variations in the beta(2)-adrenergic receptor gene may influence blood pressure levels.

Linkage and association of adrenergic and dopamine receptor genes in the distal portion of the long arm of chromosome 5 with systolic blood pressure variation

Elevated blood pressure is an important risk factor for renal-, cerebro- and cardiovascular diseases. We used an efficient discordant sib-pair ascertainment scheme to investigate the impact of the distal end of the long arm of human chromosome 5 (chromosomal region 5q31.1-qter) containing genes for the alpha1B and beta2 adrenergic receptors and the dopamine receptor type 1A on variation of systolic blood pressure in young Caucasians. We measured eight highly polymorphic markers spanning this positional candidate gene-rich region in 427 individuals from 55 three-generation pedigrees containing 69 discordant sibling pairs, and calculated multipoint identity by descent (MIBD) probabilities. The results of genetic linkage and association tests indicate that the region between markers D5S2093 and D5S462 is significantly linked to one or more polymorphic genes influencing interindividual variation in systolic blood pressure levels. Since the alpha1B adrenergic receptor and dopamine receptor type 1A genes are located close to these markers, these data suggest that genetic variation in one or both of these G protein-coupled receptors, which participate in the control of vascular tone, plays an important role in influencing interindividual variation in systolic blood pressure levels.

Partial triplication and deletion of 13q: study of a family presenting with bilateral retinoblastomas

This report compares the pathogenetic influences of selective deletion and triplicaton of chromosome 13 derived from a familial 12;13 insertional translocation. In the proband a heritable chromosomal basis for his bilateral retinoblastomas is established [46,XY,del (13) (pter leads to q12.5: :q22.1 leads to qter)mat], and in his sister the relatively modest effects of triplication of the mid-portions of 13q are demonstrated [46,XX,ins(12;13) (12pter leads to 12p11.2: :13q22.1 leads to 13q12.5: :12p11.2 leads to 12qter)mat]. Qualitative and quantitative gene marker studies and chromosomal staining techniques to differentiate timing of DNA replication failed to indicate functional gene changes about the breakpoints.

The relationship between number of striae of Retzius and their periodicity in imbricational enamel formation

Imbricational crown formation times (ICFTs) estimated from the number of perikymata on tooth surfaces are error-prone because the number of days between adjacent perikymata varies across individuals and species, and is only visible within tooth microstructure. We investigated striae of Retzius (SR) numbers (analogous to perikymata numbers), SR periodicities (days between SR or perikymata), and ICFTs for a mandibular canine sample (n=49) from medieval Denmark. We tested the relationship between SR number and periodicity to determine whether regression formulae could be produced that would allow periodicity (and ICFTs) to be determined from surface perikymata numbers. Periodicities (range=7-11 days, mode=8) and SR numbers (range=142-257, mean=190.3, s.d.=27.5) were normally distributed; ICFTs were non-normal (mean=1,594 days, s.d.=65.7). We tested periodicity as a quadratic, linear, and log-log transform linear function of SR number and found an inverse relationship (quadratic: R2=0.9504; linear: R2=0.9138; log-log transform: R2=0.9418; all p<0.001) that allowed estimation of periodicity from SR or perikymata numbers in this population and tooth type. If periodicity and SR number are inversely related in other hominin taxa, studies that have estimated ICFT by multiplying perikymata number by a human modal periodicity value or made inferences about development based only on perikymata numbers may have introduced substantial error into their ICFT estimates and life history inferences. The inverse relationship is similar to that predicted by a model of SR formation in which the ICFT for a given tooth type and population is held constant and all combinations of periodicity and SR number result in the same ICFT. However, we found that lower periodicities had longer ICFTs and higher periodicities had shorter ICFTs than the model predicted, suggesting that the model may not reflect the real process, or that there are other factors (e.g., sample size, misclassification, sexual dimorphism) also affecting the relationship between periodicity and SR number.

Alpha-1-antitrypsin deficiency in aneurysmal disease

alpha 1-Antitrypsin (alpha 1-AT) deficiency may play a role in arterial aneurysmal disease by allowing increased proteolysis of arterial structural proteins. Alpha 1-AT levels are influenced by variation at the PI (protease inhibitor) locus. PI phenotypes were determined in 173 patients with abdominal aortic aneurysms (77 from Pittsburgh, 96 from London) and in 72 patients with intracranial aneurysms (26 from Pittsburgh, 46 from London). No excess of PI deficiency alleles was observed in either of the aortic aneurysm data sets or in the Pittsburgh intracranial aneurysm data. The PI*Z deficiency allele frequency in the London intracranial aneurysm data was 8-fold higher than in controls; however, this was not significant after correcting for multiple comparisons. PI phenotype had no effect on aneurysm age-at-diagnosis within any of the data sets. Smoking history had an effect on aneurysm age-at-diagnosis only within the Pittsburgh intracranial-aneurysm data.

Ovulation detection methods for urinary hormones: precision, daily and intermittent sampling and a combined hierarchical method

BACKGROUND

We evaluate the performance of ovulation detection methods and present new approaches, including evaluation of methods for precision, combining multiple markers into a hierarchical system and using ovulation markers in intermittent sampling designs.

METHODS

With serum LH peak day as the 'gold standard' of ovulation, we estimated accuracy and precision of ovulation day algorithms using 30 ovulatory menstrual cycles with daily urinary and serum hormones and transvaginal ultrasound. Sensitivity and specificity for estimating the presence of ovulation were tested using visually assessed ovulatory (30) and anovulatory (22) cycles.

RESULTS

Sensitivity and specificity ranged from 70 to 100% for estimating presence of ovulation with twice-per-cycle, weekly, twice weekly, every-other-day and daily specimens. A combined hierarchical method estimated ovulation day using daily specimens within +/-2 days of the gold standard in 93% of cases. Accuracy of estimating ovulation day within +/-2 days using intermittent sampling ranged from 40% (weekly sampling) to 97% (every-other-day).

CONCLUSIONS

A combined hierarchical algorithm using precise and accurate markers allows maximal use of available data for efficient and objective identification of ovulation using daily specimens. In intermittent sampling designs, the presence and the timing of ovulation can be estimated with good sensitivity, specificity and accuracy.

Mapping X-linked ophthalmic diseases: II. Linkage relationship of X-linked retinitis pigmentosa to X chromosomal short arm markers

X-linked retinitis pigmentosa (XLRP) is a series of hereditary dystrophic diseases of the retina that occur in three clinically distinguishable variants: the classic form (McK31360), a type known as choroidoretinal dystrophy (McK30330), and a variant with golden-metallic or "tapetal" reflex in the heterozygote (McK30320). Controversy exists as to whether these phenotypic differences are due to clinical variability in disease expression, heterogeneity in disease alleles at a single locus, or a multiplicity of loci for XLRP. We have studied a single large kindred segregating for XLRP with the metallic fundus reflex in the heterozygote with restriction fragment length polymorphisms (RFLPs) from the short arm of the human X chromosome, and found measurable linkage to DXS7 (theta = 12.5 cMorgans at LOD = 2.5), the same RFLP previously shown by others to be tightly linked to the other forms of XLRP at theta = 3 cM. Although these estimates appeared to be different, each fell just within the 95% probability interval of the other and, therefore, were insufficient to prove or disprove that the metallic sheen form of XLRP is allelic with other forms of XLRP. Additional RFLPs at the DXS43 and the ornithine transcarbamoylase loci provided three-point crosses for determining the relative positions of DXS7 and XLRP, and supported an order that placed this form of XLRP distal to DXS7 on the Xp. Until the question of genetic heterogeneity is resolved, careful phenotypic characterization of the clinical type of XLRP present in families being used for linkage analyses is advisable.

The association between vitamin D receptor gene polymorphisms and bone mineral density at the spine, hip and whole-body in premenopausal women

The genetic influence on bone mineral density (BMD) is thought to be mediated in part by alleles at the vitamin D receptor (VDR) locus. In order to assess the effect of VDR on BMD in premenopausal women, we studied 470 healthy white subjects, aged 44-50 years, participating in the Women's Healthy Lifestyle Project. Each participant was genotyped for the BsmI polymorphism at the VDR gene locus. BMD at the lumbar spine, hip and whole-body, and the whole-body soft tissue composition, were measured cross-sectionally using a Hologic QDR 2000 densitometer. The presence of a polymorphic restriction site at the VDR gene locus was specified as b, whereas absence of this site was B. The frequency distribution of the VDR genotype was: bb, 20.6%; Bb, 39.1%; and BB, 40.2%. Spinal BMD (mean +/- SD) was significantly lower in women with VDR genotype BB (1.038 +/- 0.11 g/cm2) as compared with those with genotype bb (1.069 +/- 0.12 g/cm2, p < 0.05). Trochanter BMD was 2.7% lower in those with genotype BB versus bb (0.685 +/- 0.10 g/cm2 vs 0.708 +/- 0.09 g/cm2). A similar trend was shown at each subregion of the hip, but not at the whole-body. In premenopausal women, allelic status at the VDR locus contributed to variations in spinal and trochanteric BMDs, but the absolute difference in BMDs was small, amounting to 0.26 and 0.23 standard deviations, respectively. It is concluded that in this population of healthy premenopausal women there was a significant association between polymorphisms at the VDR gene locus and both spinal and trochanteric BMDs, yet no association was demonstrated for the whole-body BMD.

Monitoring reproductive aging in a 5-year prospective study: aggregate and individual changes in steroid hormones and menstrual cycle lengths with age

OBJECTIVE

We describe a 5-year prospective study of reproductive aging, and present analyses of steroid hormone and menstrual cycle changes with age.

DESIGN

Participants were college-educated white women, primarily of northern European ancestry, recruited from the Tremin Research Program on Women's Health (n = 156, 25-58 years). In each of 5 consecutive years, they collected daily urine specimens for 6 months and recorded menstrual bleeds for all months. Urine specimens were assayed for estrone-3-glucuronide (E1G) and pregnanediol-3-glucuronide (PDG), urinary metabolites of estradiol and progesterone. Using multilevel models, we estimated hormone and cycle-length trajectories for individual women and within- and between-woman variance by age.

RESULTS

At the aggregate level, PDG declined beginning in the 30s, E1G increased into the 40s before declining, and cycle length became more variable with age. Individual-level models revealed substantial hormonal variation across women, in both absolute levels and rates of change. Most women showed declining E1G by the late 40s, declining PDG in the 30s, and increasing mean cycle length in the 40s. Hormonal variation decreased with age; cycle length variation decreased and then increased. Within individual women, cycle lengths were highly variable while hormone levels were more stable. Women differed more from each other in hormone levels than for cycle lengths.

CONCLUSIONS

Aggregate-level analyses show general changes in steroid hormones and cycle length but cannot show variation within and across women. Individuals' cycle lengths were too variable to predict hormone levels. Clinicians should obtain more data on individual women's hormonal patterns when determining fertility or menopause treatments.

Potential trends in Attention Deficit Hyperactivity Disorder (ADHD) drug use on a college campus: wastewater analysis of amphetamine and ritalinic acid

Attention Deficit Hyperactivity Disorder (ADHD) medication use is on the rise in the United States. The most widely used ADHD medications are the amphetamine-type compounds Adderall (mixed amphetamine salts) and Ritalin (methylphenidate). According to survey data ADHD medications are used as a study drug or "Smart Drug" by students without a prescription on college campuses. Survey data of non-prescribed drug use has limitations with accurate reporting and no empirical data of usage exists in the literature. This study looks for trends in the use of these drugs on a college campus among low-stress and high stress periods. The metabolites of these two drugs, amphetamine and ritalinic acid, are quantified in campus wastewater using solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Trends show a possible increase in amphetamine levels during periods of high stress such as midterms, the last week of classes and finals week over levels from the baseline low stress weeks such as the first week of classes. Both semesters from the 2011-12 academic year were studied and the highest increase over baseline (760%) occurred during finals week of the second semester. Ritalinic acid levels gradually climbed first semester but had no obvious periodic trend second semester.

Nitrobacter winogradskyi transcriptomic response to low and high ammonium concentrations

Nitrobacter winogradskyi Nb-255 is a nitrite-oxidizing bacterium that can grow solely on nitrite (NO2(-)) as a source of energy and nitrogen. In most natural situations, NO2(-) oxidation is coupled closely to ammonium (NH4(+)) oxidation by bacteria and archaea and, conceptually, N. winogradskyi can save energy using NH4(+) to meet its N-biosynthetic requirements. Interestingly, NH4(+) delayed the growth of N. winogradskyi when at concentrations higher than 35 mM, but grew well at concentrations below 25 mM NH4(+) while adjusting the expression of 24% of its genes. Notable genes that changed in expression included those with roles in nitrogen and carbon assimilation. Contrary to expectations, higher expression of glutamate synthase (GOGAT), instead of glutamate dehydrogenase, was detected at higher NH4(+) concentration. Genes in assimilatory NO2(-) metabolism and the degradation of glycogen and biofilm/motility were downregulated when N. winogradskyi was grown in the presence of NH4(+). Nitrobacter winogradskyi grown in medium with 25 mM NH4(+) upregulated genes in post-translational modification, protein turnover, biogenesis and chaperons. The data suggest that N. winogradskyi physiology is modified in the presence of NH4(+) and is likely to be modified during coupled nitrification with NH3 oxidizers.

The temporal dynamics of the fourteenth-century Black Death: new evidence from English ecclesiastical records

Recent research has questioned whether the European Black Death of 1347-1351 could possibly have been caused by the bubonic plague bacillus Yersinia pestis, as has been assumed for over a century. Central to the arguments both for and against involvement of Y. pestis has been a comparison of the temporal dynamics observed in confirmed outbreaks of bubonic plague in early-20th-century India, versus those reconstructed for the Black Death from English church records--specifically, from lists of institutions (appointments) to vacated benefices contained in surviving bishops' registers. This comparison is, however, based on a statistical error arising from the fact that most of the bishops' registers give only the dates of institution and not the dates of death. Failure to correct for a distributed (as opposed to constant) lag time from death to institution has made it look as if the Black Death passed slowly through specific localities. This error is compounded by a failure to disaggregate the information from the bishops' registers to a geographical level that is genuinely comparable to the modern data. A sample of 235 deaths from the bishop's register of Coventry and Lichfield, the only English register to list both date of death and date of institution, shows that the Black Death swept through local areas much more rapidly than has previously been thought. This finding is consistent with those of earlier studies showing that the Black Death spread too rapidly between locales to have been a zoonosis such as bubonic plague. A further analysis of the determinants of the lag between death and institution, designed to provide a basis for reexamining other bishops' registers that do not provide information on date of death, shows that the distribution of lags could vary significantly by time and space even during a single epidemic outbreak.

Total and unopposed estrogen exposure across stages of the transition to menopause

Detailed characterization of estrogen dynamics during the transition to menopause is an important step toward understanding its potential implications for reproductive cancers developing in the transition years. We conducted a 5-year prospective study of endogenous levels of total and unopposed estrogen. Participants (n=108; ages 25-58 years) collected daily urine specimens for 6 months in each of 5 consecutive years. Specimens were assayed for estrone-3-glucuronide (E1G) and pregnanediol-3-glucuronide. Linear mixed-effects models were used to estimate exposure to total and unopposed estrogen by age and reproductive stage. Reproductive stage was estimated using menstrual cycle length variance. E1G mean area under the curve and mean E1G 5th and 95th percentiles represented total estrogen exposure. An algorithm identifying days of above-baseline E1G that coincided with the days of baseline pregnanediol-3-glucuronide was used to identify days of unopposed estrogen. Mean E1G area under the curve increased with age in the pretransition and early transition and decreased in the late transition. Ninety-fifth percentile E1G levels did not decline until after menopause, whereas 5th percentile levels declined from the early transition to the postmenopause. The number of days of unopposed estrogen was significantly higher during the transition compared with the pretransition. Given the length of time women spend in the transition, they are exposed to more total and unopposed estrogen than has been previously appreciated. Coupled with epidemiologic evidence on lifetime exposure to estrogen, these results suggest that variation in the amount of time spent in the transition may be an important risk factor for reproductive cancers.

COMT genotype and cognitive function: an 8-year longitudinal study in white and black elders

OBJECTIVE

Catechol-O-methyltransferase (COMT), an enzyme that catalyzes the degradation of dopamine, is necessary for cognitive function. Few studies have examined the prospective association between COMT (val(158)met) genotype and cognition in older adults.

METHODS

We assessed a biracial cohort of 2,858 elderly subjects without dementia who were followed for 8 years. The Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) were administered at baseline and years 3, 5, and 8. COMT by race, gender, and APOE status interactions were examined.

RESULTS

Stratified by race and adjusted for covariates, repeated-measures mixed-effects models showed no association between COMT genotype and baseline cognitive function in black or white subjects. In white subjects, COMT was associated with change in 3MS (Met/Met: -2.3 [0.60], Met/Val: -1.7 [0.40], and Val/Val: -1.2 [0.50]) and DSST (Met/Met: -5.60 [1.00], Met/Val: -4.80 [0.70], Val/Val: -4.00 [0.90]). In black subjects, COMT was associated with change in the DSST (Met/Met: -4.10 [2.1], Met/Val: -4.80 [0.90], Val/Val -2.60 [1.00]).

CONCLUSION

These findings suggest that the Val allele has a protective impact on cognitive decline in late life.

A macrophage migration inhibitory factor promoter polymorphism is associated with high-density parasitemia in children with malaria

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that regulates innate and adaptive immune responses to bacterial and parasitic infections. Functional promoter variants in the MIF gene influence susceptibility to inflammatory diseases in Caucasians. As the role of genetic variation in the MIF gene in conditioning malaria disease outcomes is largely unexplored, the relationship between a G to C transition at MIF -173 and susceptibility to high-density parasitemia (HDP) and severe malarial anemia (SMA) was examined in Kenyan children (aged 3-36 months; n=477) in a holoendemic Plasmodium falciparum transmission region. In a multivariate model, controlling for age, gender, HIV-1 status, and sickle-cell trait, MIF -173CC was associated with an increased risk of HDP compared to MIF -173GG. No significant associations were found between MIF -173 genotypic variants and susceptibility to SMA. Additional studies demonstrated that homozygous G alleles were associated with lower basal circulating MIF levels relative to the GC group. However, stimulation of cultured peripheral blood mononuclear cells with malarial pigment (hemozoin) increased MIF production in the GG group and decreased MIF production in the GC group. Thus, variability at MIF -173 is associated with functional changes in MIF production and susceptibility to HDP in children with malaria.

Mapping X-linked ophthalmic diseases. Provisional assignment of the locus for choroideremia to Xq13-q24

Choroideremia (McK 30310), an X-linked hereditary retinal dystrophy, causes nyctalopia, progressive visual field loss, and ultimately central blindness in affected males in early adulthood. We have used restriction fragment length polymorphisms from the X-chromosome to localize the region of the mutation for choroideremia in three families with this disorder. One polymorphic marker, DXYS1, located within Xq13-q21, shows no recombination with choroideremia at a LOD score of 5.78. Thus choroideremia maps within 9 centiMorgans of DXYS1 at 90% probability. Another marker, DXS11, located at Xq24-q26, shows no recombination with choroideremia but at a smaller LOD score of 1.54. These results suggest that the locus for choroideremia is distal to DXYS1 and between the two markers in the region Xq13-q24. This information may be useful for antenatal diagnosis, isolation of the mutant gene, and development of a rational therapy for the disorder.

Identification of genetic alterations related to chemoresistance in epithelial ovarian cancer

OBJECTIVE

After the completion of primary chemotherapy, the majority of advanced ovarian cancer patients have persistent, chemoresistant disease. Comparative genomic hybridization (CGH) has been used to study genetic alterations that may be responsible for chemoresistance in ovarian cancer. CGH is a useful, genomewide screen but resolution is limited to 5-10 Mb. Recently, quantitative microsatellite analysis (QuMA), a TaqMan-based quantitative PCR technology, has been used for higher resolution of DNA copy number abnormalities. Our goal is to identify specific chromosomal aberrations correlated with platinum resistance.

METHODS

Snap-frozen ovarian tissue samples taken from 22 patients with ovarian cancer between 1994 and 1998 were analyzed. Patients whose ovarian cancer actually demonstrated growth during platinum-combination treatment or no objective evidence of regression following four to six cycles of therapy were considered to have clinically defined platinum-resistant disease. QuMA was carried out at the following loci using the ABI Prism 7700 (TaqMan) instrument with a microsatellite repeat probe: D3S1553, D3S1617, D5S464, D5S630, D6S1581, D6S446, D8S557, D19S208, D20S196, DXS1068. Fisher's exact test, exact logistic regression, and the Cochran-Armitage trend test were used. Because of multiple hypothesis testing, the P values were adjusted with the Bonferroni procedure to limit the familywise error rate to at most 5%.

RESULTS

Of the 22 patients, 12 (54.5%) were platinum-sensitive and 10 (45.5%) were platinum-resistant. When comparing sensitive and resistant patients, no statistically significant difference was noted among stage, grade, histology, and age (P = 0.1292, P = 1.0000, P = 1.0000, P = 1.0000, respectively). In the QuMA analysis, 10 of the 14 (71.4%) patients who had a low copy number of D6S1581 were platinum-resistant, while none of the patients with a normal or high copy number of D6S1581 were platinum-resistant. This was statistically significant when the marker data were treated as either a continuous or a categorical variable (P = 0.0410 and P = 0.0170, respectively). No other loci correlated significantly with platinum resistance.

CONCLUSIONS

D6S1581 was the only genetic marker, of those examined, significantly related to chemoresistance. Patients with a loss of D6S1581 are more likely to be platinum-resistant. Identification of genetic alterations associated with platinum resistance detected by QuMA may contribute to a better understanding of clinical behavior and chemotherapy treatment options for patients.

Description of a dinucleotide repeat polymorphism in the human elastin gene and its use to confirm assignment of the gene to chromosome 7

Informative polymorphisms have been very difficult to detect in the elastin gene, and this has hampered the analysis of heritable connective tissue disorders, notably the Marfan syndrome. We have recently detected a dinucleotide repeat polymorphism in intron 17 of the human elastin gene consisting of 8 alleles with sizes between 161 and 175 bp. Analysis of 540 chromosomes from unrelated Caucasian individuals revealed a bimodal frequency distribution typical of (dC-dA)n.(dG-dT)n repeat polymorphisms, with allele frequencies ranging from 0.004 (161 bp) to 0.574 (163 bp). As the elastin gene was originally assigned to chromosome 2q31-ter and because more recent data have suggested an assignment to 7q11.1-21.1, we have genotyped a sub-set of the CEPH pedigrees and carried out pairwise linkage analysis with markers on chromosomes 7 and 2. Lod-scores of between +3.70 and +13.69 were obtained with markers spanning 7p13-q22.1, whilst negative lod-scores were observed with the chromosome 2 markers. Analysis of type II human ovarian teratomas placed the elastin gene within 11 cM of the centromere on chromosome 7. Additionally, we detected the dinucleotide repeat in human-rodent cell hybrids containing chromosome 7, but not those containing chromosome 2. These data confirm the assignment of elastin to chromosome 7 and provide a new, highly informative marker for the analysis of heritable disorders of connective tissue for which elastin is a candidate gene.

Enhanced B Cell Alloantigen Presentation and Its Epigenetic Dysregulation in Liver Transplant Rejection

T cell suppression prevents acute cellular rejection but causes life-threatening infections and malignancies. Previously, liver transplant (LTx) rejection in children was associated with the single-nucleotide polymorphism (SNP) rs9296068 upstream of the HLA-DOA gene. HLA-DOA inhibits B cell presentation of antigen, a potentially novel antirejection drug target. Using archived samples from 122 white pediatric LTx patients (including 77 described previously), we confirmed the association between rs9296068 and LTx rejection (p = 0.001, odds ratio [OR] 2.55). Next-generation sequencing revealed that the putative transcription factor (CCCTC binding factor [CTCF]) binding SNP locus rs2395304, in linkage disequilibrium with rs9296068 (D' 0.578, r(2) = 0.4), is also associated with LTx rejection (p = 0.008, OR 2.34). Furthermore, LTx rejection is associated with enhanced B cell presentation of donor antigen relative to HLA-nonidentical antigen in a novel cell-based assay and with a downregulated HLA-DOA gene in a subset of these children. In lymphoblastoid B (Raji) cells, rs2395304 coimmunoprecipitates with CTCF, and CTCF knockdown with morpholino antisense oligonucleotides enhances alloantigen presentation and downregulates the HLA-DOA gene, reproducing observations made with HLA-DOA knockdown and clinical rejection. Alloantigen presentation is suppressed by inhibitors of methylation and histone deacetylation, reproducing observations made during resolution of rejection. Enhanced donor antigen presentation by B cells and its epigenetic dysregulation via the HLA-DOA gene represent novel opportunities for surveillance and treatment of transplant rejection.

The length of perimenopausal menstrual cycles increases later and to a greater degree than previously reported

OBJECTIVE

To demonstrate that the perimenopausal increase in menstrual cycle length presented by Treloar et al. was biased by misidentified menopause dates, mean values classified by calendar year, and exclusion of menstrual cycles straddling two calendar years; and to use the revised data to investigate women's experiences of longer perimenopausal cycles.

DESIGN

Secondary analysis of prospectively collected menstrual cycle data.

SETTING

Center for Population and Health, Georgetown University.

PATIENT(S)

One hundred twenty white, college-educated, US women in the Tremin Research Program on Women's Health.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Mean cycle length and time spent in >40-day cycles, by year before menopause.

RESULT(S)

Mean estimates for each of the 4 years before menopause were 30.48, 35.02, 45.15, and 80.22 days, respectively, compared with the original analysis: 33.60, 43.91, 55.87, and 54.58 days. In the year before menopause, the majority of women spent >or=75% of their time in cycles >40 days long.

CONCLUSION(S)

Treloar's estimates of mean cycle length were biased. Long cycles occurred throughout perimenopause, but the largest increase in mean cycle length did not occur until the final year before menopause. New estimates of the time spent in cycles >40 days may be useful clinically as well as epidemiologically for assessing menopausal onset and symptomatology.

Monitoring reproductive aging in a 5-year prospective study: aggregate and individual changes in luteinizing hormone and follicle-stimulating hormone with age

OBJECTIVE

This study describes age-related changes in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in a 5-year prospective study of reproductive aging.

DESIGN

Participants (n = 156 college-educated, white, US women; 25 to 58 y) were recruited from the TREMIN Research Program on Women's Health. They collected daily urine specimens for 6 months in each of 5 consecutive years. Specimens were assayed for LH and FSH. Aggregate changes were calculated in LH and FSH with age, and multilevel models were used to estimate individual hormone trajectories and within-woman and between-woman variances by age.

RESULTS

Aggregate LH levels increased beginning after age 45; FSH increased at all ages, accelerating after age 45. Individual-level patterns with age included the following: reproductive-age LH and FSH levels, with increasing FSH and increasing or decreasing LH (ages 20 to 49); rapidly increasing LH and FSH (ages 40 to 59); and increasing or steady postmenopausal LH and FSH (ages 46 to 62). FSH levels were consistently high in the latter category, but LH levels overlapped with levels found in younger women (<45 y). Individual LH patterns showed more variability (5% to 35% of total variance) than FSH (3% to 22% of total variance). Both hormones had relatively low variation within individuals compared with between-woman differences (65% to 97% of total variance).

CONCLUSIONS

Aggregate-level data do not reflect differences across women and oversimplify the age-related increases and variability in LH and FSH. Individual FSH levels are not distinguishable from reproductive-age levels until after rapid perimenopausal increases in FSH occur; individuals vary in whether their postmenopausal LH levels are distinguishable from reproductive-age levels.