A -436C>A polymorphism in the human FAS gene promoter associated with severe childhood malaria.
ABSTRACT: Human genetics and immune responses are considered to critically influence the outcome of malaria infections including life-threatening syndromes caused by Plasmodium falciparum. An important role in immune regulation is assigned to the apoptosis-signaling cell surface receptor CD95 (Fas, APO-1), encoded by the gene FAS. Here, a candidate-gene association study including variant discovery at the FAS gene locus was carried out in a case-control group comprising 1,195 pediatric cases of severe falciparum malaria and 769 unaffected controls from a region highly endemic for malaria in Ghana, West Africa. We found the A allele of c.-436C>A (rs9658676) located in the promoter region of FAS to be significantly associated with protection from severe childhood malaria (odds ratio 0.71, 95% confidence interval 0.58-0.88, p(empirical)?=?0.02) and confirmed this finding in a replication group of 1,412 additional severe malaria cases and 2,659 community controls from the same geographic area. The combined analysis resulted in an odds ratio of 0.71 (95% confidence interval 0.62-0.80, p?=?1.8×10??, n?=?6035). The association applied to c.-436AA homozygotes (odds ratio 0.47, 95% confidence interval 0.36-0.60) and to a lesser extent to c.-436AC heterozygotes (odds ratio 0.73, 95% confidence interval 0.63-0.84), and also to all phenotypic subgroups studied, including severe malaria anemia, cerebral malaria, and other malaria complications. Quantitative FACS analyses assessing CD95 surface expression of peripheral blood mononuclear cells of naïve donors showed a significantly higher proportion of CD69+CD95+ cells among persons homozygous for the protective A allele compared to AC heterozygotes and CC homozygotes, indicating a functional role of the associated CD95 variant, possibly in supporting lymphocyte apoptosis.
Project description:<h4>Background</h4>Alcohol has been reported to be a common and modifiable risk factor for hypertension. However, observational studies are subject to confounding by other behavioural and sociodemographic factors, while clinical trials are difficult to implement and have limited follow-up time. Mendelian randomization can provide robust evidence on the nature of this association by use of a common polymorphism in aldehyde dehydrogenase 2 (ALDH2) as a surrogate for measuring alcohol consumption. ALDH2 encodes a major enzyme involved in alcohol metabolism. Individuals homozygous for the null variant (*2*2) experience adverse symptoms when drinking alcohol and consequently drink considerably less alcohol than wild-type homozygotes (*1*1) or heterozygotes. We hypothesise that this polymorphism may influence the risk of hypertension by affecting alcohol drinking behaviour.<h4>Methods and findings</h4>We carried out fixed effect meta-analyses of the ALDH2 genotype with blood pressure (five studies, n = 7,658) and hypertension (three studies, n = 4,219) using studies identified via systematic review. In males, we obtained an overall odds ratio of 2.42 (95% confidence interval [CI] 1.66-3.55, p = 4.8 x 10(-6)) for hypertension comparing *1*1 with *2*2 homozygotes and an odds ratio of 1.72 (95% CI 1.17-2.52, p = 0.006) comparing heterozygotes (surrogate for moderate drinkers) with *2*2 homozygotes. Systolic blood pressure was 7.44 mmHg (95% CI 5.39-9.49, p = 1.1 x 10(-12)) greater among *1*1 than among *2*2 homozygotes, and 4.24 mmHg (95% CI 2.18-6.31, p = 0.00005) greater among heterozygotes than among *2*2 homozygotes.<h4>Conclusions</h4>These findings support the hypothesis that alcohol intake has a marked effect on blood pressure and the risk of hypertension.
Project description:Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening thrombotic microangiopathy caused by severe ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs 13) deficiency, recurring in 30-50% of patients. The common human leukocyte antigen (HLA) variant rs6903608 was found to be associated with prevalent iTTP, but whether this variant is associated with disease relapse is unknown. To estimate the impact of rs6903608 on iTTP onset and relapse, we performed a case-control and cohort study in 161 Italian patients with a first iTTP episode between 2002 and 2018, and in 456 Italian controls. Variation in rs6903608 was strongly associated with iTTP onset (homozygotes odds ratio (OR) 4.68 (95% confidence interval (CI) 2.67 to 8.23); heterozygotes OR 1.64 (95%CI 0.95 to 2.83)), which occurred over three years earlier for each extra risk allele (? -3.34, 95%CI -6.69 to 0.02). Of 153 survivors (median follow-up 4.9 years (95%CI 3.7 to 6.1)), 44 (29%) relapsed. The risk allele homozygotes had a 46% (95%CI 36 to 57%) absolute risk of relapse by year 6, which was significantly higher than both heterozygotes (22% (95%CI 16 to 29%)) and reference allele homozygotes (30% (95%CI 23 to 39%)). In conclusion, HLA variant rs6903608 is a risk factor for both iTTP onset and relapse. This newly identified biomarker may help with recognizing patients at high risk of relapse, who would benefit from close monitoring or intensified immunosuppressive therapy.
Project description:Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it predisposes carriers to hemolysis. This fact supports the protection hypothesis against malaria. The aim of this systematic review is to assess the presence and the extent of protective association between G6PD deficiency and malaria. Thirteen databases were searched for papers reporting any G6PD alteration in malaria patients. Twenty-eight of the included 30 studies were eligible for the meta-analysis. Results showed absence of negative association between G6PD deficiency and uncomplicated falciparum malaria (odds ratio (OR), 0.77; 95% confidence interval (CI), 0.59-1.02; p?=?0.07). However, this negative association happened in Africa (OR, 0.59; 95% CI, 0.40-0.86; p?=?0.007) but not in Asia (OR, 1.24; 95% CI, 0.96-1.61; p?=?0.10), and in the heterozygotes (OR, 0.70; 95% CI, 0.57-0.87; p?=?0.001) but not the homo/hemizygous (OR, 0.70; 95% CI, 0.46-1.07; p?=?0.10). There was no association between G6PD deficiency and total severe malaria (OR, 0.82; 95% CI, 0.61-1.11; p?=?0.20). Similarly, there was no association with other malaria species. G6PD deficiency can potentially protect against uncomplicated malaria in African countries, but not severe malaria. Interestingly, this protection was mainly in heterozygous, being x-linked thus related to gender.
Project description:BACKGROUND: The most common form of malaria outside Africa, Plasmodium vivax, is more difficult to control than P. falciparum because of the latent liver hypnozoite stage, which causes multiple relapses and provides an infectious reservoir. The African (A-) G6PD (glucose-6-phosphate dehydrogenase) deficiency confers partial protection against severe P. falciparum. Recent evidence suggests that the deficiency also confers protection against P. vivax, which could explain its wide geographical distribution in human populations. The deficiency has a potentially serious interaction with antirelapse therapies (8-aminoquinolines such as primaquine). If the level of protection was sufficient, antirelapse therapy could become more widely available. We therefore tested the hypothesis that G6PD deficiency is protective against vivax malaria infection. METHODS AND FINDINGS: A case-control study design was used amongst Afghan refugees in Pakistan. The frequency of phenotypic and genotypic G6PD deficiency in individuals with vivax malaria was compared against controls who had not had malaria in the previous two years. Phenotypic G6PD deficiency was less common amongst cases than controls (cases: 4/372 [1.1%] versus controls 42/743 [5.7%]; adjusted odds ratio [AOR] 0.18 [95% confidence interval (CI) 0.06-0.52], p = 0.001). Genetic analysis demonstrated that the G6PD deficiency allele identified (Mediterranean type) was associated with protection in hemizygous deficient males (AOR = 0.12 [95% CI 0.02-0.92], p = 0.041). The deficiency was also protective in females carrying the deficiency gene as heterozygotes or homozygotes (pooled AOR = 0.37 [95% CI 0.15-0.94], p = 0.037). CONCLUSIONS: G6PD deficiency (Mediterranean type) conferred significant protection against vivax malaria infection in this population whether measured by phenotype or genotype, indicating a possible evolutionary role for vivax malaria in the selective retention of the G6PD deficiency trait in human populations. Further work is required on the genotypic protection associated with other types of G6PD deficiency and on developing simple point-of-care technologies to detect it before administering antirelapse therapy.
Project description:The variant alleles in the mannose binding lectin-2 (MBL-2) gene have been associated with MBL deficiency and increased susceptibility to sepsis. We postulate that the variant MBL-2 genotypes are associated with increased susceptibility to and mortality in acute respiratory distress syndrome (ARDS).Nested case-control study.Tertiary academic medical center.Two hundred and twelve Caucasians with ARDS and 442 controls genotyped for the variant X, D, B, and C alleles of codon -221, 52, 54, and 57, respectively.None.Patients homozygous for the variant codon 54B allele (54BB) had worse severity of illness on admission (p = .007), greater likelihood of septic shock (p = .04), and increased odds of ARDS (adjusted odds ratio, 6.7; 95% confidence interval, 1.5-31) when compared with heterozygotes and homozygotes for the wild-type allele. This association with ARDS was especially strong among the 311 patients with septic shock (adjusted odds ratio, 12.0; 95% confidence interval, 1.9-74). Among the patients with ARDS, the 54BB genotype was associated with more daily organ dysfunction (p = .01) and higher mortality (adjusted hazard rate, 4.0; 95% confidence interval, 1.6-10). Development of ARDS and outcomes in ARDS did not vary significantly with variant alleles of codon -221, 52, and 57, but the power to detect an effect was limited secondary to the low allele frequencies.The MBL-2 codon 54BB genotype may be important in ARDS susceptibility and outcome. Additional studies are needed to confirm these findings in other populations.
Project description:Dengue illness has been a major health concern in Pakistan during the last decade. Dengue infection can result in a spectrum of clinically distinct outcomes, ranging from asymptomatic infection to potentially life-threatening forms of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). A single-nucleotide polymorphism in Fc?RIIa (rs1801274) results in altered affinity of the receptor for different subclasses of immunoglobulin G, and is a key player in determining the susceptibility to or protection from severe clinical infection of dengue. In this study, we analyzed the allelic and genotypic distribution of rs1801274 in subjects of Pakistani origin with subclinical dengue infection (n = 40), dengue fever (DF) (n = 40), and DHF/DSS (n = 30). We found that HH homozygotes and heterozygotes were significantly more likely to develop clinical dengue (odds ratio [OR] = 3.21, 95% confidence interval [CI] = 1.29-7.97, P = 0.009), either DF (OR = 2.82, 95% CI = 1.00-7.97, P = 0.045) or DHF/DSS (OR = 3.90, 95% CI = 1.13-13.07, P = 0.024) than the asymptomatic dengue infection. Results of allelic distribution comparisons and logistic regression analysis also supported the same relationship. The results suggest complex nature of interacting factors in determining the course for severe dengue illness.
Project description:BACKGROUND: In case-control studies of Europeans, heterozygosity for Arg702Trp(rs2066844), Gly908Arg(rs2066845) and Leu1007fsinsC(rs5743293) on the NOD2/CARD15 gene is associated with a 2-fold greater risk of Crohn disease, whereas homozygosity or compound heterozygosity is associated with a 17-fold greater risk. However, the importance of these genetic variants if identified in particular individuals within the general population is unknown. We undertook this study to estimate the penetrance of these variants in the general population. METHODS: We genotyped 43,596 individuals from the Danish general population followed between January 1976 and July 2007. Using a logistic regression model, we estimated the risk of Crohn disease in relation to variants of the NOD2/CARD15 gene in the general population. Penetrance was calculated as the fraction of participants in whom Crohn disease was diagnosed before age 50 years. RESULTS: In the general population, 89% of participants were noncarriers of the genetic variants of interest (n = 38,594), 11% were heterozygotes (n = 4838), and 0.4% were compound heterozygotes or homozygotes (n = 164). For Crohn disease, multifactorially adjusted odds ratios were 1.2 (95% confidence interval [CI] 0.8-1.9) for heterozygotes and 3.3 (95% CI 0.8-13.6) for compound heterozygotes and homozygotes combined, relative to noncarriers. Only 2 compound heterozygotes received a diagnosis of Crohn disease, and this disease was not diagnosed in any of the homozygotes. The penetrance at age 50 years of NOD2/CARD15 genetic variants of Crohn disease was 0.30% (95% CI 0.29%-0.31%) for heterozygotes and 1.5% (95% CI 1.4%-1.6%) for compound heterozygotes and homozygotes. INTERPRETATION: The penetrance of NOD2/CARD15 genetic variants in relation to risk of Crohn disease for this Danish population was lower than might have been expected from previous European case-control studies. This should be considered when advising healthy individuals in whom these genetic variants are identified.
Project description:Glucose-6-phosphate dehydrogenase (G6PD) enzyme function and genotype were determined in Ugandan children with uncomplicated falciparum malaria enrolled in a primaquine trial after exclusion of severe G6PD deficiency by fluorescent spot test. G6PD A- heterozygotes and hemizygotes/homozygotes experienced dose-dependent lower hemoglobin concentrations after treatment. No severe anemia was observed.
Project description:<h4>Objectives</h4>This study aimed to assess malaria seroprevalence among acute febrile illness cases who come for health care seeking in the high malaria-endemic setting of North West Ethiopia.<h4>Methods</h4>Institutional-based descriptive serosurvey of malaria infections was employed among 18,386 febrile patients from September 2020 to August 2021. Data were entered using Epi Data version 4.2 and exported to STATA (SE) R-14 version statistical software for further analysis. Bi-variable and multivariable regression analyses were conducted to identify malaria infection. Finally, variables with P-value less than 0.05 were considered significant predictors for malaria infection.<h4>Results</h4>The mean (±standard deviation) age of participants was 48.6 (±18.4) years. The overall seroprevalence of malaria infection was estimated as 27.8% (95% confidence interval = 27.2; 28.6, standard error = 0.003). Malaria infection was significantly associated with participants being female (adjusted odds ratio = 2.9; 95% confidence interval = 1.8; 3.7, P = 0.01), age 5-29 years (adjusted odds ratio = 2.2; 95% confidence interval = 1.7; 2.8, P = 0.02), rural (adjusted odds ratio = 3.9; 95% confidence interval = 1.9; 4.4, P = 0.001), and Hgb ⩽11 mg/dL (adjusted odds ratio = 3.4; 95% confidence interval = 1.9; 5.86, P = 0.01).<h4>Conclusion</h4>Nearly every three to ten acute febrile cases were positive for confirmed malaria infection. The risk of malaria infection was significantly associated with respondents being female, aged 5-29 years, rural, and levels of hemoglobin were significantly associated with malaria infection.
Project description:INTRODUCTION:The stroma is the supportive framework of biologic tissue in the breast, consisting of various proteins such as the proteoglycans, decorin and lumican. Altered expression of decorin and lumican is associated with breast tumors. We hypothesized that genetic variation in the decorin (DCN) and lumican (LUM) genes may contribute to breast cancer. METHODS:We investigated associations of 14 common polymorphisms in the DCN and LUM genes with 798 breast cancer cases and 843 controls from Mayo Clinic, MN, USA. One polymorphism per gene with the strongest risk association in the Mayo Clinic sample was genotyped in 4,470 breast cancer cases and 4,560 controls from East Anglia, England (Studies of Epidemiology and Risk Factors in Cancer Heredity (SEARCH)). RESULTS:In the Mayo Clinic sample, six polymorphisms were associated with breast cancer risk (P trend <or= 0.05). The association with LUM rs2268578, evaluated further in SEARCH, was positive, although the odds ratios (OR) were weaker and not statistically significant. ORs were 1.4 (95% confidence interval [CI], 1.1 to 1.8) for heterozygotes and 2.2 (95% CI, 1.1 to 4.3; P2 df = 0.002) for homozygotes in the Mayo Clinic sample, and were 1.1 (95% CI, 0.9 to 1.2) for heterozygotes and 1.4 (95% CI, 1.0 to 2.1; P2 df = 0.13) for homozygotes in the SEARCH sample. In combined analyses, the ORs were 1.1 (95% CI, 1.0 to 1.2) for heterozygotes and 1.6 (95% CI, 1.2 to 2.3; P2 df = 0.005) for homozygotes. Positive associations for this polymorphism were observed for estrogen receptor-positive tumors in both the Mayo Clinic sample (OR for heterozygotes = 1.5, 1.1 to 1.9 and OR for homozygotes = 2.5, 1.2 to 5.3;P2 df = 0.001) and the SEARCH sample (OR for heterozygotes = 1.0, 0.9 to 1.1 and OR for homozygotes = 1.6, 1.0 to 2.5; P2 df = 0.10). In combined analyses, the ORs were 1.1 (95% CI, 0.9 to 1.2) for heterozygotes and 1.9 (95% CI, 1.3 to 2.8; P2 df = 0.001) for homozygotes. CONCLUSIONS:Although LUM rs2268578 was associated with breast cancer in the Mayo Clinic study, particularly estrogen receptor-positive breast cancer, weaker and modest associations were observed in the SEARCH sample. These modest associations will require larger samples to adequately assess the importance of this polymorphism in breast cancer.