Male Homozygotes Research Articles

Population suppression with dominant female-lethal alleles is boosted by homing gene drive

BackgroundMethods to suppress pest insect populations using genetic constructs and repeated releases of male homozygotes have recently been shown to be an attractive alternative to older sterile insect techniques based on radiation. Female-specific lethal alleles have substantially increased power, but still require large, sustained transgenic insect releases. Gene drive alleles bias their own inheritance to spread throughout populations, potentially allowing population suppression with a single, small-size release. However, suppression drives often suffer from efficiency issues, and the most well-studied type, homing drives, tend to spread without limit.ResultsIn this study, we show that coupling female-specific lethal alleles with homing gene drive allowed substantial improvement in efficiency while still retaining the self-limiting nature (and thus confinement) of a lethal allele strategy. Using a mosquito model, we show the required release sizes for population elimination in a variety of scenarios, including different density growth curves, with comparisons to other systems. Resistance alleles reduced the power of this method, but these could be overcome by targeting an essential gene with the drive while also providing rescue. A proof-of-principle demonstration of this system in Drosophila melanogaster was effective in both biasing its inheritance and achieving high lethality among females that inherit the construct in the absence of antibiotic.ConclusionsOverall, our study shows that substantial improvements can be achieved in female-specific lethal systems for population suppression by combining them with various types of gene drive.

Hemochromatosis Genetic Variants and Musculoskeletal Outcomes: 11.5-Year Follow-Up in the UK Biobank Cohort Study.

The iron overload disorder hemochromatosis is primarily caused by the homozygous HFE p.C282Y variant, but the scale of excess related musculoskeletal morbidity is uncertain. We estimated hemochromatosis-genotype associations with clinically diagnosed musculoskeletal outcomes and joint replacement surgeries in the UK Biobank community cohort. A total of 451,143 European ancestry participants (40 to 70 years at baseline) were followed in hospital records (mean 11.5-years). Cox proportional hazards models estimated HFE p.C282Y and p.H63D associations with incident outcomes. Male p.C282Y homozygotes (n = 1294) had increased incidence of osteoarthritis (n = 52, hazard ratio [HR]: 2.12 [95% confidence interval, CI: 1.61 to 2.80]; p = 8.8 × 10-8), hip replacement (n = 88, HR: 1.84 [95% CI: 1.49 to 2.27]; p = 1.6 × 10-8), knee replacement (n = 61, HR: 1.54 [95% CI: 1.20 to 1.98]; p = 8.4 × 10-4), and ankle and shoulder replacement, compared to males with no HFE mutations. Cumulative incidence analysis, using Kaplan-Meier lifetable probabilities demonstrated 10.4% of male homozygotes were projected to develop osteoarthritis and 15.5% to have hip replacements by age 75, versus 5.0% and 8.7% respectively without mutations. Male p.C282Y homozygotes also had increased incidence of femoral fractures (n = 15, HR: 1.72 [95% CI: 1.03 to 2.87]; p = 0.04) and osteoporosis (n = 21, HR: 1.71 [95% CI: 1.11 to 2.64]; p = 0.02), although the latter association was limited to those with liver fibrosis/cirrhosis diagnoses. Female p.C282Y homozygotes had increased incidence of osteoarthritis only (n = 57, HR: 1.46, [95% CI: 1.12 to 1.89]; p = 0.01). Male p.C282Y/p.H63D compound heterozygotes experienced a modest increased risk of hip replacements (n = 234, HR: 1.17 [95% CI: 1.02 to 1.33], p = 0.02), but this did not pass multiple testing corrections. In this large community cohort, the p.C282Y homozygote genotype was associated with substantial excess musculoskeletal morbidity in males. Wider HFE genotype testing may be justified, including in orthopedic clinics serving higher HFE variant prevalence populations. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

PS-BPB01-7: ANGIOTENSIN II INDUCES AORTIC RUPTURE AND DISSECTION IN OSTEOPROTEGERIN-DEFICIENT MICE

Background: The biological mechanism of action for osteoprotegerin (OPG), a soluble decoy receptor for the receptor activator of nuclear factor kappa-B ligand (RANKL) in the vascular structure, has not been elucidated. The study aim was to determine if OPG affects aortic structural integrity in angiotensin II-induced hypertension. Methods and Results: Mortality was higher (P < 0.0001 by Log-rank test) in 8-week-old male homozygotes of OPG gene knockout (OPG -/- mice given subcutaneous administration of angiotensin II (1,000 ng/kg/min) for 28 days, with an incidence of 21% fatal aortic rupture (Chi-square, 8.024, P = 0.005), and 23% aortic dissection (Chi-square, 4.285, P = 0.038), than in age-matched wild type mice. The absence of OPG was associated with decreased medial and adventitial thickness and increased numbers of elastin breaks as well as with 2.5-fold increased periostin expression and soluble RANKL concentrations. PEGylated human recombinant OPG administration decreased all-causes mortality (-22%, P < 0.001 by Log-rank test), the incidence of fatal aortic rupture (-13%, P = 0.08), and aortic dissection (-23%, P < 0.001) with decreasing numbers of elastin breaks (P = 0.0539) at the supra-renal aorta, periostin expressions (P = 0.0011), and soluble RANKL concentrations (P = 0.0012) in angiotensin II-infused OPG-/- mice. Conclusions: These data suggest that OPG protects against aortic rupture and dissection in Ang II-induced hypertension by inhibiting RANKL activity and periostin expression.

Association of Genetic Variant Linked to Hemochromatosis With Brain Magnetic Resonance Imaging Measures of Iron and Movement Disorders

Hereditary hemochromatosis (HH) is an autosomal recessive genetic disorder that leads to iron overload. Conflicting results from previous research has led some to believe the brain is spared the toxic effects of iron in HH. To test the association of the strongest genetic risk variant for HH on brainwide measures sensitive to iron deposition and the rates of movement disorders in a substantially larger sample than previous studies of its kind. This cross-sectional retrospective study included participants from the UK Biobank, a population-based sample. Genotype, health record, and neuroimaging data were collected from January 2006 to May 2021. Data analysis was conducted from January 2021 to April 2022. Disorders tested included movement disorders (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10], codes G20-G26), abnormalities of gait and mobility (ICD-10 codes R26), and other disorders of the nervous system (ICD-10 codes G90-G99). Homozygosity for p.C282Y, the largest known genetic risk factor for HH. T2-weighted and T2* signal intensity from brain magnetic resonance imaging scans, measures sensitive to iron deposition, and clinical diagnosis of neurological disorders. The total cohort consisted of 488 288 individuals (264 719 female; ages 49-87 years, largely northern European ancestry), 2889 of whom were p.C282Y homozygotes. The neuroimaging analysis consisted of 836 individuals: 165 p.C282Y homozygotes (99 female) and 671 matched controls (399 female). A total of 206 individuals were excluded from analysis due to withdrawal of consent. Neuroimaging analysis showed that p.C282Y homozygosity was associated with decreased T2-weighted and T2* signal intensity in subcortical motor structures (basal ganglia, thalamus, red nucleus, and cerebellum; Cohen d >1) consistent with substantial iron deposition. Across the whole UK Biobank (2889 p.C282Y homozygotes, 485 399 controls), we found a significantly increased prevalence for movement disorders in male homozygotes (OR, 1.80; 95% CI, 1.28-2.55; P = .001) but not female individuals (OR, 1.09; 95% CI, 0.70-1.73; P = .69). Among the 31 p.C282Y male homozygotes with a movement disorder, only 10 had a concurrent HH diagnosis. These findings indicate increased iron deposition in subcortical motor circuits in p.C282Y homozygotes and confirm an increased association with movement disorders in male homozygotes. Early treatment in HH effectively prevents the negative consequences of iron overload in the liver and heart. Our work suggests that screening for p.C282Y homozygosity in high-risk individuals also has the potential to reduce brain iron accumulation and to reduce the risk of movement disorders among male individuals who are homozygous for this mutation.

Angiotensin II Induces Aortic Rupture and Dissection in Osteoprotegerin-Deficient Mice.

BackgroundThe biological mechanism of action for osteoprotegerin, a soluble decoy receptor for the receptor activator of nuclear factor‐kappa B ligand in the vascular structure, has not been elucidated. The study aim was to determine if osteoprotegerin affects aortic structural integrity in angiotensin II (Ang II)‐induced hypertension.Methods and ResultsMortality was higher (P<0.0001 by log‐rank test) in 8‐week‐old male homozygotes of osteoprotegerin gene‐knockout mice given subcutaneous administration of Ang II for 28 days, with an incidence of 21% fatal aortic rupture and 23% aortic dissection, than in age‐matched wild‐type mice. Ang II‐infused aorta of wild‐type mice showed that osteoprotegerin immunoreactivity was present with proteoglycan. The absence of osteoprotegerin was associated with decreased medial and adventitial thickness and increased numbers of elastin breaks as well as with increased periostin expression and soluble receptor activator of nuclear factor‐kappa B ligand concentrations. PEGylated human recombinant osteoprotegerin administration decreased all‐cause mortality (P<0.001 by log‐rank test), the incidence of fatal aortic rupture (P=0.08), and aortic dissection (P<0.001) with decreasing numbers of elastin breaks, periostin expressions, and soluble receptor activator of nuclear factor‐kappa B ligand concentrations in Ang II‐infused osteoprotegerin gene‐knockout mice.ConclusionsThese data suggest that osteoprotegerin protects against aortic rupture and dissection in Ang II‐induced hypertension by inhibiting receptor activator of nuclear factor‐kappa B ligand activity and periostin expression.

Sex modifies APOE ε4 dose effect on brain tau deposition in cognitively impaired individuals.

Recent studies in cognitively unimpaired elderly individuals suggest that the APOE ε4 allele exerts a dosage-dependent effect on brain tau deposition. The aim of this study was to investigate sex differences in APOE ε4 gene dosage effects on brain tau deposition in cognitively impaired individuals using quantitative 18F-flortaucipir PET.Preprocessed 18F-flortaucipir tau PET images, T1-weighted structural MRI, demographic information, global cortical amyloid-β burden measured by 18F-florbetapir PET, CSF total tau and phosphorylated tau measurements were obtained from the Alzheimer’s Disease Neuroimaging Initiative database. Two hundred and sixty-eight cognitively impaired individuals with 146 APOE ε4 non-carriers and 122 carriers (85 heterozygotes and 37 homozygotes) were included in the study. An iterative reblurred Van Cittert iteration partial volume correction method was applied to all downloaded PET images. Magnetic resonance images were used for PET spatial normalization. Twelve regional standardized uptake value ratios relative to the cerebellum were computed in standard space. APOE ε4 dosage × sex interaction effect on 18F-flortaucipir standardized uptake value ratios was assessed using generalized linear models and sex-stratified analysis.We observed a significant APOE ε4 dosage × sex interaction effect on tau deposition in the lateral temporal, posterior cingulate, medial temporal, inferior temporal, entorhinal cortex, amygdala, parahippocampal gyrus regions after adjusting for age and education level (P < 0.05). The medial temporal, entorhinal cortex, amygdala and parahippocampal gyrus regions retained a significant APOE ε4 dosage × sex interaction effect on tau deposition after adjusting for global cortical amyloid-β (P < 0.05). In sex-stratified analysis, there was no significant difference in tau deposition between female homozygotes and heterozygotes (P > 0.05). In contrast, male homozygotes standardized uptake value ratios were significantly greater than heterozygotes or non-carriers throughout all 12 regions of interest (P < 0.05). Female heterozygotes exhibited significantly increased tau deposition compared to male heterozygotes in the orbitofrontal, posterior cingulate, lateral temporal, inferior temporal, entorhinal cortex, amygdala and parahippocampal gyrus (P < 0.05). Results from voxel-wise analysis were similar to the ones obtained from regions of interest analysis.Our findings indicate that an APOE ε4 dosage effect on brain region-specific tau deposition exists in males, but not females. These results have important clinical implications towards developing sex and genotype-guided therapeutics in Alzheimer’s disease and uncovers a potential explanation underlying differential APOE ε4-associated Alzheimer’s risk in males and females.

Depression Augments Plasma APOA4 without Changes of Plasma Lipids and Glucose in Female Adolescents Carrying G Allele of APOA4 rs5104.

The association of apolipoprotein AIV (APOA4) with depression or plasma levels of lipids and glucose has been inconsistently reported. However, interplays between APOA4 and depression on the levels have not been explored yet. The present study aimed to investigate plasma levels of APOA4, lipids, and glucose in adolescents with different genotypes of APOA4 rs5104 and with or without depression. Depressive symptoms were assessed in 631 adolescents by Beck Depression Inventory (BDI). A total score of 14 was defined as the cutoff point for depression. Plasma levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, and insulin were measured by routine methods, and APOA4 by enzyme-linked immunosorbent assays. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analyses and verified by DNA sequencing. Female adolescents had higher prevalence of depression than male subjects only in G allele carriers (p=0.015), but not in AA homozygotes. Risk factors of depression and predictors of depression severity were different between G allele carriers and AA homozygotes. Lower levels of glucose (p=0.003) were observed in male G allele carriers than those in male AA homozygotes and increased TG levels (p=0.008) in female G allele carriers when compared with those in female AA homozygotes. When both APOA4 rs5104 and depression were taken into account, subjects with depression had higher levels of plasma APOA4 than adolescents without depression only in female G allele carriers (p=0.043), but no significant changes of plasma lipids and glucose. Depression augments plasma APOA4 levels without changes of plasma lipids and glucose in female adolescents carrying G allele of APOA4 rs5104. These results may provide a novel explanation for the inconsistent relationship between depression, APOA4, and plasma levels of lipids and glucose in the literature.

Adipocyte-specific deletion of Tcf7l2 induces dysregulated lipid metabolism and impairs glucose tolerance in mice

Aims/hypothesisTranscription factor 7-like 2 (TCF7L2) is a downstream effector of the Wnt/β-catenin signalling pathway implicated in type 2 diabetes risk through genome-wide association studies. Although its expression is critical for adipocyte development, the potential roles of changes in adipose tissue TCF7L2 levels in diabetes risk are poorly defined. Here, we investigated whether forced changes in Tcf7l2 expression in adipocytes affect whole body glucose or lipid metabolism and crosstalk between disease-relevant tissues.MethodsTcf7l2 was selectively ablated in mature adipocytes in C57BL/6J mice using Cre recombinase under Adipoq promoter control to recombine Tcf7l2 alleles floxed at exon 1 (referred to as aTCF7L2 mice). aTCF7L2 mice were fed normal chow or a high-fat diet for 12 weeks. Glucose and insulin sensitivity, as well as beta cell function, were assessed in vivo and in vitro. Levels of circulating NEFA, selected hormones and adipokines were measured using standard assays.ResultsReduced TCF7L2 expression in adipocytes altered glucose tolerance and insulin secretion in male but not in female mice. Thus, on a normal chow diet, male heterozygote knockout mice (aTCF7L2het) exhibited impaired glucose tolerance at 16 weeks (p = 0.03) and increased fat mass (1.4 ± 0.1-fold, p = 0.007) but no changes in insulin secretion. In contrast, male homozygote knockout (aTCF7L2hom) mice displayed normal body weight but impaired oral glucose tolerance at 16 weeks (p = 0.0001). These changes were mechanistically associated with impaired in vitro glucose-stimulated insulin secretion (decreased 0.5 ± 0.1-fold vs control mice, p = 0.02) and decreased levels of the incretins glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (0.6 ± 0.1-fold and 0.4 ± 0.1-fold vs control mice, p = 0.04 and p < 0.0001, respectively). Circulating levels of plasma NEFA and fatty acid binding protein 4 were increased by 1.3 ± 0.1-fold and 1.8 ± 0.3-fold vs control mice (p = 0.03 and p = 0.05, respectively). Following exposure to a high-fat diet for 12 weeks, male aTCF7L2hom mice exhibited reduced in vivo glucose-stimulated insulin secretion (0.5 ± 0.1-fold vs control mice, p = 0.02).Conclusions/interpretationLoss of Tcf7l2 gene expression selectively in adipocytes leads to a sexually dimorphic phenotype, with impairments not only in adipocytes, but also in pancreatic islet and enteroendocrine cells in male mice only. Our findings suggest novel roles for adipokines and incretins in the effects of diabetes-associated variants in TCF7L2, and further illuminate the roles of TCF7L2 in glucose homeostasis and diabetes risk.Graphical abstract

A common variant in OXTR rs53576 impacts topological patterns of brain functional networks.

A common variant (rs53576, G/A) in the oxytocin receptor (OXTR) gene is associated with individual differences in social behavior and may increase the risk for neuropsychiatric disorders characterized by social impairment, especially autism. Although recent functional magnetic resonance imaging (fMRI) studies have identified functional connectivity alteration in some brain regions in risk A allele carriers, it is currently unknown whether this dysfunctional connectivity causes disruption of the topological properties of brain functional networks. We applied a graph-theoretical analysis to investigate the topological properties of brain networks derived from resting-state fMRI in relation to AA homozygotes versus G allele carriers in 290 cognitive normal young adults. We found both AA homozygotes and G allele carriers demonstrated small-world properties; however, male AA homozygotes showed lower normalized clustering coefficient, small-worldness, and local efficiency compared with male G allele carriers, no differences survived after Bonferroni correction; and the inter-group differences of all three metrics exhibited an allele-load-dependent trend (AA < AG < GG), indicating a randomization shift of their brain functional networks. No significant results were observed in any global measures in female AA homozygotes as compared to female G allele carriers. Our results suggested that the topological patterns of brain functional networks were altered in OXTR rs53576 male homozygotes for the risk A allele compared with male G allele carriers, providing evidence for the disruption of integrity in large-scale intrinsic brain networks in a sex-dimorphic manner.

Relationship Between the rs7341475 Polymorphism and DNA Methylation in the Reelin Gene and Schizophrenia Symptoms

Objectives. To identify relationships between the rs7341475 polymorphism and methylation of the reelin gene on the one hand and the severity of schizophrenia symptomatology and the neuropsychological indicator – semantic verbal fluency (VF) – on the other. Materials and methods. Genotypes at the rs7341475 locus were determined in 556 patients with schizophrenia spectrum disorders. PANSS evaluations were obtained for 549 of these patients and 221 were tested for semantic VF. The relationship between methylation of the reelin 5’ region and promotor and the severity of PANSS syndromes and VF was assessed using data from 35 patients using the five-factor PANSS model. Results. A relationship was found between genotype at the rs7341475 locus and PANSS measures (a sex-genotype interaction effect: F = 2.70, p = 0.020). Male homozygotes for the common G allele showed the lowest levels of positive syndrome. Verbal fluency was linked with the characteristics of the methylation of the reelin gene promoter. Conclusions. The results obtained here suggest that the rs7341475 polymorphism may be related to variation in positive symptomatology in men. At the same time, the pattern of methylation of the reelin gene is important for retention of VF – with higher levels of methylation in the transcription initiation site and low levels in the distal part of the promoter.

Association between Transcription Factor AP-2B genotype, obesity, insulin resistance and dietary intake in a longitudinal birth cohort study.

The development of obesity has a large genetic component, and the gene encoding the transcription factor 2 beta (TFAP2B) has been identified as one of the responsible factors. We investigated the effect of TFAP2B intron 2 variable number tandem repeat (VNTR) genotype on obesity, insulin resistance and dietary intake from 15 to 33 years of age. The sample included both birth cohorts (originally n = 1176) of the longitudinal Estonian Children Personality Behaviour and Health Study. The association between TFAP2B genotype, and anthropometric measurements, glucose metabolism and dietary intake at ages 15, 18 and 25 years was assessed using the linear mixed-effects regression models. Differences in anthropometric measurements, biochemical measures, blood pressure and dietary intake between TFAP2B genotypes at different age, including data of the older cohort at age 33, were assessed by one-way ANOVA. Male homozygotes for the TFAP2B 5-repeat allele had significantly higher body weight, body mass index, sum of 5 skinfolds, proportion of body fat, waist circumference, hip circumference, waist-to-hip ratio, waist-to-height ratio, fasting insulin and HOMA index. In female subjects, homozygotes for the TFAP2B 5-repeat allele had significantly larger increase in the rate of change per year in body weight, body mass index and hip circumference between years 15 and 25. By age 33, the findings were similar. A decrease in daily energy intake from adolescence to young adulthood was observed. In males, heterozygotes had significantly smaller decrease in the rate of change per year in daily energy intake. The association of TFAP2B with the development of obesity and insulin resistance is present throughout adolescence to young adulthood in males. In females the effect of TFAP2B on obesity appears later, in young adulthood. The TFAP2B effect is rather related to differences in metabolism than energy intake.

Apoptosis in Spermiogenesis of Multiple Robertsonian Heterozygotes of Mus musculus domesticus

Mus musculus domesticus is a species that is characterized by a diploid number of 40 chromosomes, all telocentrics (acrocentrics). In natural populations of Mus with high frequency Robertsonian chromosome translocations (RBs), a fusion at centromere-level between two autosomal telocentric, producing metacentric Rb chromosomes and a variety of natural subspecies with diploid chromosome numbers below 40. Rb chromosomes do not affect the viability of individuals but mainly fertility of Rb heterozygotes. In their meiosis the metacentric Rb and the homologous telocentrics form trivalents that have problems in synapsis and segregation. This paper presents a comparative analysis of spermatogenesis considering the stages of the epithelium and the number of germ cells loss by apoptosis comparing heterozygote males 2n=32, carriers 8 trivalents, and homozygotes 2n=40 and 2n=24. It was found that the number of spermatocytes in first prophase was similar in the different seminiferous epithelium stages in all the chromosome constitutions. In the 2n=32 heterozygotes a significant decreased number of spermatids was reflected in the proportion of spermatocytes and spermatids that was 1:1.7. In the homozygote males rare germ cell in apoptosis (positive for caspase 3) were observed, which were mainly concentrated in the XII stage of the seminiferous epithelium. In heterozygote spermatocytes apoptotic germ cell number was significantly higher than that registered in homozygote males, and generally correspond to spermatocytes in meiotic divisions. This selective removal of cells possibly carrying anomalies, either in chromosome alignment or segregation, is consistent with the smaller number of spermatids and the relative sub-fertility observed in 2n=32 Rb heterozygotes.

Hemochromatisis HFE mutations: Penetrance in 451,000 adults of European descent

Introduction HFE C282Y mutations account for the majority of hereditary hemochromatosis (HH) in people of European descent. HH is characterised by progressive accumulation of iron, plus chronic pain, exhaustion, arthritis, diabetes, liver cirrhosis and liver cancer. Previous studies (mainly in 20- to 50-year-olds) suggested that development of related disease in those with the mutation was uncommon. As a result of the claimed low penetrance, identification of additional cases within families is advised, but screening is not recommended. Methods We estimated C282Y homozygote associations with morbidity and mortality in 40- to 70-year-old UK Biobank volunteers, from England, Scotland and Wales. We included 451,243 subjects of European descent, and tested baseline and incident disease and mortality associations during follow-up (maximum 9.7 years). Follow-up was through hospital records, cancer registry and death certificates. Odds ratios and Cox hazard ratios were adjusted for age, sex and technical covariates. Results There were n = 2890 C282Y homozygote subjects (0.64% of the 451,243 subjects, or 1 in 156). Excess morbidity was most common in older men (age 60 to 70). C282Y homozygous status was associated with increased presence of hemochromatosis, liver disease, diabetes, arthritis, osteoporosis, pneumonia and polymyalgia rheumatica. Overall, 51.8% of older male C282Y homozygotes had ≥ 1 of the associated diagnoses, compared to 28.6% of those with the wild type (common) genotype: odds ratio = 2.63 95% CI: 2.23 to 3.10, P = 3.1 × 10−31. Increased risks for the associated conditions were also present in older women and younger groups but were less common. There was a modest increase in morbidity in heterozygotes. Conclusion We conclude that HFE C282Y homozygosity has a far higher penetrance than previously reported, and is a major contributor to common disease occurrence, especially with advancing age. The case for systematic early identification of iron overload related to HFE mutations needs to be re-examined.

Population-Based Analysis of Cluster Headache-Associated Genetic Polymorphisms.

Cluster headache is a disorder with increased hereditary risk. Associations between cluster headache and polymorphism rs2653349 of the HCRTR2 gene have been demonstrated. The less common allele (A) seems to reduce disease susceptibility. The polymorphism rs5443 of the GNB3 gene positively influences triptan treatment response. Carriers of the mutated T allele are more likely to respond positively compared to C:C homozygotes, when treated with triptans. DNA was extracted from buccal swabs obtained from 636 non-related Southeastern European Caucasian individuals and was analyzed by real-time PCR. Gene distribution for the rs2653349 was G:G = 79.1%, G:A = 19.2%, and A:A = 1.7%. The frequency of the wild-type G allele was 88.7%. The frequencies for rs5443 were C:C = 44.0%, C:T = 42.6%, and T:T = 13.4%. The frequency of the wild-type C allele was 65.3%. The frequency distribution of rs2653349 in the Southeastern European Caucasian population differs significantly when compared with other European and East Asian populations, and the frequency distribution of rs5443 showed a statistically significant difference between Southeastern European Caucasian and African, South Asian, and East Asian populations. For rs2653349, a marginal statistically significant difference between genders was found (p = 0.080) for A:A versus G:G and G:A genotypes (OR = 2.78), indicating a higher representation of male homozygotes for the protective mutant A:A allele than female. No statistically significant difference was observed between genders for rs5443. Cluster headache pathophysiology and pharmacotherapy response may be affected by genetic factors, indicating the significant role of genotyping in the overall treatment effectiveness of cluster headaches.

The Plasminogen Activator Inhibitor 1 4G/5G Polymorphism and the Risk of Alzheimer's Disease.

The aim of this study was to determine whether plasminogen activator inhibitor 1 (PAI-1) is associated with the risk of Alzheimer's disease (AD) in Tunisian patients. We analyzed the genotype and allele frequency distribution of the PAI-1 polymorphism in 60 Tunisian patients with AD and 120 healthy controls. The results show a significantly increased risk of AD in carriers of the 4G/4G and 4G/5G genotypes versus the wild-type 5G/5G genotype (4G/4G: 28.33% in patients vs 10.0% in controls; P < 10-3; OR = 8.78; 4G/5G: 55.0% in patients vs 38.33% in controls; OR = 4.45; P < 10-3). The 4G allele was also more frequently found in patients compared with controls; P < 10-3; OR = 3.07. For all participants and by gender, homozygotic carriers (4G/4G) were at an increased risk of AD over heterozygotes and women were at an increased risk over their male genotype counterparts. The odds ratio for AD among 4G/4G carriers for any group was approximately twice that of heterozygotes in the same group. Women homozygotes ranked highest for AD risk (OR = 20.8) and, in fact, women heterozygotes (OR = 9.03) ranked higher for risk than male homozygotes (OR = 6.12). These preliminary exploratory results should be confirmed in a larger study.

Population Screening for Hereditary Haemochromatosis in Australia: Construction and Validation of a State-Transition Cost-Effectiveness Model.

Introduction HFE-associated haemochromatosis, the most common monogenic disorder amongst populations of northern European ancestry, is characterised by iron overload. Excess iron is stored in parenchymal tissues, leading to morbidity and mortality. Population screening programmes are likely to improve early diagnosis, thereby decreasing associated disease. Our aim was to develop and validate a health economics model of screening using utilities and costs from a haemochromatosis cohort.MethodsA state-transition model was developed with Markov states based on disease severity. Australian males (aged 30 years) and females (aged 45 years) of northern European ancestry were the target populations. The screening strategy was the status quo approach in Australia; the model was run over a lifetime horizon. Costs were estimated from the government perspective and reported in 2015 Australian dollars ($A); costs and quality-adjusted life-years (QALYs) were discounted at 5% annually. Model validity was assessed using goodness-of-fit analyses. Second-order Monte-Carlo simulation was used to account for uncertainty in multiple parameters.ResultsFor validity, the model reproduced mortality, life expectancy (LE) and prevalence rates in line with published data. LE for C282Y homozygote males and females were 49.9 and 40.2 years, respectively, slightly lower than population rates. Mean (95% confidence interval) QALYS were 15.7 (7.7–23.7) for males and 14.4 (6.7–22.1) for females. Mean discounted lifetime costs for C282Y homozygotes were $A22,737 (3670–85,793) for males and $A13,840 (1335–67,377) for females. Sensitivity analyses revealed discount rates and prevalence had the greatest impacts on outcomes.ConclusionWe have developed a transparent, validated health economics model of C282Y homozygote haemochromatosis. The model will be useful to decision makers to identify cost-effective screening strategies.

Sphingomyelin Synthase 1 Is Essential for Male Fertility in Mice.

Sphingolipids and the derived gangliosides have critical functions in spermatogenesis, thus mutations in genes involved in sphingolipid biogenesis are often associated with male infertility. We have generated a transgenic mouse line carrying an insertion in the sphingomyelin synthase gene Sms1, the enzyme which generates sphingomyelin species in the Golgi apparatus. We describe the spermatogenesis defect of Sms1-/- mice, which is characterized by sloughing of spermatocytes and spermatids, causing progressive infertility of male homozygotes. Lipid profiling revealed a reduction in several long chain unsaturated phosphatidylcholins, lysophosphatidylcholins and sphingolipids in the testes of mutants. Multi-Spectral Optoacoustic Tomography indicated blood-testis barrier dysfunction. A supplementary diet of the essential omega-3 docosahexaenoic acid and eicosapentaenoic acid diminished germ cell sloughing from the seminiferous epithelium and restored spermatogenesis and fertility in 50% of previously infertile mutants. Our findings indicate that SMS1 has a wider than anticipated role in testis polyunsaturated fatty acid homeostasis and for male fertility.

Treating homozygous familial hypercholesterolemia in a real-world setting: Experiences with lomitapide

Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disease characterised by markedly elevated plasma levels of low-density lipoprotein-cholesterol (LDL-C). Lomitapide is a microsomal triglyceride transfer protein (MTP) inhibitor approved as an adjunct to other lipid-lowering therapies (LLTs), with or without lipoprotein apheresis (LA), for the treatment of adult HoFH. Diet with <20% calories from fat is required. Due to a varying genetic and phenotypic profile of patients with HoFH, individual patients may respond to therapy differently; therefore examining individual cases in a ‘real-world’ setting provides valuable information on the effective day-to-day management of HoFH cases. Four HoFH cases were selected for analysis and discussion: a 20-year-old female compound heterozygote; a 62-year old female homozygote; a 42-year-old female compound heterozygote; and a 36-year-old male homozygote. Each patient was commenced on lomitapide according to the prescribed protocol and subjected to routine follow-up. All four patients experienced clinically meaningful reductions in LDL-C levels of 35–73%. Three of the patients had evidence of steatosis or mildly elevated liver function tests) before lomitapide was started, but effects of lomitapide on hepatic function were not universal. Three of the patients experienced gastrointestinal adverse events, but were managed with appropriate dietary control. Lomitapide is an effective adjunct LLT in the management of patients with HoFH, with or without LA. Real-world use of lomitapide has a side-effect profile consistent with clinical trials and one that can be managed by adherence to recommendations on dose escalation, dietary modification and dietary supplements.

Target-site resistance mutations (kdr and RDL), but not metabolic resistance, negatively impact male mating competiveness in the malaria vector Anopheles gambiae.

The implementation of successful insecticide resistance management strategies for malaria control is currently hampered by poor understanding of the fitness cost of resistance on mosquito populations, including their mating competiveness. To fill this knowledge gap, coupled and uncoupled Anopheles gambiae s.l. males (all M form (Anopheles coluzzii)) were collected from mating swarms in Burkina Faso. This multiple insecticide resistant population exhibited high 1014F kdrR allele frequencies (>60%) and RDLR (>80%) in contrast to the Ace-1R allele (<6%). Kdr heterozygote males were more likely to mate than homozygote resistant (OR=2.36; P<0.001), suggesting a negative impact of kdr on An. coluzzii mating ability. Interestingly, heterozygote males were also more competitive than homozygote susceptible (OR=3.26; P=0.006), suggesting a heterozygote advantage effect. Similarly, heterozygote RDLR/RDLS were also more likely to mate than homozygote-resistant males (OR=2.58; P=0.007). Furthermore, an additive mating disadvantage was detected in male homozygotes for both kdr/RDL-resistant alleles. In contrast, no fitness difference was observed for the Ace-1 mutation. Comparative microarray-based genome-wide transcription analysis revealed that metabolic resistance did not significantly alter the mating competitiveness of male An. coluzzii mosquitoes. Indeed, no significant difference of expression levels was observed for the main metabolic resistance genes, suggesting that metabolic resistance has a limited impact on male mating competiveness. In addition, specific gene classes/GO terms associated with mating process were detected including sensory perception and peroxidase activity. The detrimental impact of insecticide resistance on mating competiveness observed here suggests that resistance management strategies such as insecticide rotation could help reverse the resistance, if implemented early.

The BNP gene polymorphism as a regulator of brain natriuretic peptide plasma level in men with uncomplicated essential hypertension and left ventricular hypertrophy

Aim: The BNP biomarker application optimization for myocardial dysfunction diagnosis in men citizens of Podillia region in Ukraine with uncomplicated essential hypertension and left ventricular hypertrophy by determining the plasma levels in patients with different BNP gene variants. Methods. We examined 141 men, age 40 – 60 years, who live in Podillia region. Among them 62 men were diagnosed uncomplicated EH with left ventricular hypertrophy (stages 1 and 2) and CHF I-II classes according to NYHA Classification. 79 healthy men were included into the control group. The patients with uncomplicated EH and the healthy men were representative by age. The BNP (T-381C) gene polymorphism was determined by PCR, and the level of BNP plasma concentrations was established by ELISA. Results. In both healthy men and patients with uncomplicated EH with LVH, residents of Podillia region, age 40-60 years, dominates the T381C genotype and the C allele of the BNP gene. It was found that any inherited variant of the BNP gene was not associated with the risk of developing uncomplicated EH with LVH in men residents of Podillia region. However, carriers of the C381C genotype and the C allele of the BNP gene have significantly higher levels of BNP in plasma in both healthy men and patients with uncomplicated EH and LVH, residents of Podillia region, age 40-60 years. There are calculated levels of BNP that can be used for screening of large groups of people for early diagnosis of uncomplicated EH with LVH: BNP boundary level ≥ 82,41 pg/ml ables to diagnose uncomplicated EH with LVH in male carriers of the C allele heterozygote carriers of the genotypes T381C and C381C of the BNP gene; BNP boundary level ≥ 45,34 pg/ml ables to diagnose uncomplicated EH with LVH in male homozygote carriers of the T381T genotype of the BNP gene.