新疆维吾尔族和汉族亚甲基四氢叶酸还原酶基因多态性研究

目的:研究新疆维吾尔族、汉族两民族亚甲基四氢叶酸还原酶(Methyleneterahyofolate reductase MTHFR)基因多态性的分布情况,获取新疆维吾尔族与汉族MTHFR 1298位群体遗传学数据。方法:应用PCR-RFLP技术检测新疆维吾尔族及汉族MTHFR1298位多态性位点基因频率及基因型频率。结果:新疆维吾尔族、汉族MTHFR 1298位C等位基因分布频率分别为12%、23%,P<0.05有统计学差异性,且新疆维吾尔族MTHFR 1298位C等位基因分布频率与现有报道的少数民族贵州苗族、布依族具有统计学差异。结论:MTHFR 1298位多态性在不同民族具有差异性:MTHFR 1298位多态性在新疆维吾尔族和汉族有民族差异;新疆新疆维吾尔族MTHFR 1298位C等位基因频率与贵州苗族、布依族少数民族之间具有民族差异性。     

Folate Metabolism Gene 5,10-Methylenetetrahydrofolate Reductase (MTHFR) Is Associated with ADHD in Myelomeningocele Patients

The objective of this study was to examine the relation between the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene and behaviors related to attention- deficit/hyperactivity disorder (ADHD) in individuals with myelomeningocele. The rationale for the study was twofold: folate metabolizing genes, (e.g. MTHFR), are important not only in the etiology of neural tube defects but are also critical to cognitive function; and individuals with myelomeningocele have an elevated incidence of ADHD. Here, we tested 478 individuals with myelomeningocele for attention-deficit hyperactivity disorder behavior using the Swanson Nolan Achenbach Pelham-IV ADHD rating scale. Myelomeningocele participants in this group for whom DNAs were available were genotyped for seven single nucleotide polymorphisms (SNPs) in the MTHFR gene. The SNPs were evaluated for an association with manifestation of the ADHD phenotype in children with myelomeningocele. The data show that 28.7% of myelomeningocele participants exhibit rating scale elevations consistent with ADHD; of these 70.1% had scores consistent with the predominantly inattentive subtype. In addition, we also show a positive association between the SNP rs4846049 in the 3′-untranslated region of the MTHFR gene and the attention-deficit hyperactivity disorder phenotype in myelomeningocele participants. These results lend further support to the finding that behavior related to ADHD is more prevalent in patients with myelomeningocele than in the general population. These data also indicate the potential importance of the MTHFR gene in the etiology of the ADHD phenotype.     

Population Study of Frequency of Methylenetetrahydrofolate Reductase C677T Gene Polymorphism in Yakutia

The enzyme methylenetetrahydrofolate reductase (MTHFR) catalyzes synthesis of 5-methylenehydrofolate, which is the methyl donor for the conversion of homocysteine to methionine. According to the numerous literature data, polymorphic variant of the MTHFR-encoding gene, C677T, is associated with hyperhomocysteinemia, vascular pathologies, neural tube defects, dementia, perinatal mortality, mental disorders, long-term neurodegenerative disorders, lens displacement, arachnodactyly, and venous thromboses. The present study was focused on the analysis of the C677T polymorphism (missence mutation leading to the replacement of cytosine by thymine at position 677) of the MTHFR gene in three indigenous populations of the Republic of Sakha (Yakutia), living in the settlements of Cheriktei, Byadi, and Dyupsya. Comparison of the genotype and allele frequencies revealed no substantial differences between the three Yakut populations, as well as between Yakuts and other Mongoloid ethnic groups.     

利用LightCycler研究食管鳞状细胞癌与MTHFR C677T多态性的关系

亚甲基四氢叶酸还原酶(MTHFR)在叶酸代谢中起重要作用.MTHFR基因第677位核苷酸的多态性(C→T)能影响其酶活性并与肿瘤易感性有关.为比较中国北方人群MTHFR C677T多态性与食管鳞状细胞癌(ESCC)易感性之间的关系, 通过高速实时聚合酶链反应(real-time PCR)和解链曲线(melting curve)方法分析了189名ESCC患者和141名健康对照的MTHFR C677T多态性位点的基因型.结果显示,健康对照组的MTHFR C/C(纯合野生)、C/T和T/T(纯合突变)基因型的频率分别为17.7%、38.3%和44.0%.ESCC患者的T/T基因型频率(42.3%)与健康对照组无显著差异(χ2=0.089, P＞0.05),其C/T基因型频率(49.2%)仅略高于对照组(χ2＝3.890, P＜0.05),而患者组的C/C基因型频率(8.5%)显著低于健康对照组(17.7%) (χ2=6.37, P=0.012).与C/T和T/T基因型相比,C/C基因型可显著降低ESCC的发病风险(相对风险度的比值比(OR)=0.43, 95%可信区间(CI)=0.22～0.84),在吸烟者和有上消化道肿瘤家族史的患者中这一倾向更加明显.研究提示,在中国北方人群中, MTHFR C677T纯合野生基因型对ESCC的发病起保护作用.     

Association between Methylenetetrahydrofolate Reductase C677T Polymorphism and Susceptibility to Cervical Cancer: A Meta-Analysis

Background

To assess the association between MTHFR polymorphism and cervical cancer risk, a meta-analysis was performed.

Methods

Based on comprehensive searches of the PubMed, Embase, and Web of Science databases, we identified outcome data from all articles estimating the association between MTHFR polymorphism and cervical cancer risk. The pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated.

Results

A total of 12 studies with 2,924 cases (331 cervical intraepithelial neoplasia (CIN) I, 742 CIN II/III, 1851 invasive cervical cancer) and 2,581 controls were identified. There was no significant association between MTHFR C677T polymorphism and CIN I risk (T vs. C, OR = 1.10, 95% CI = 0.92–1.31; TT vs. CC, OR = 1.14, 95% CI = 0.78–1.68; TT+CT vs. CC, OR = 1.22, 95% CI = 0.94–1.58; TT vs. CT+CC, OR = 0.99, 95% CI = 0.70–1.40). For the CIN II/III, lack of an association was also found (T vs. C, OR = 1.08, 95% CI = 0.95–1.23; TT vs. CC, OR = 1.15, 95% CI = 0.87–1.52; TT+CT vs. CC, OR = 1.13, 95% CI = 0.94–1.35; TT vs. CT+CC, OR = 1.07, 95% CI = 0.83–1.38). The T allele had significant association to susceptibility of invasive cervical cancer in recessive model (TT vs. CT+CC, OR = 1.23, 95% CI = 1.02–1.49). On subgroup analysis by ethnicity, similarly significant differences in T vs. C, TT vs. CC, and recessive model were found in Asians.

Conclusion

The present meta-analysis suggested that MTHFR C677T polymorphism were to substantially contribute to invasive cervical cancer in recessive model.     

Maternal Methylenetetrahydrofolate Reductase C677T Polymorphism and Down Syndrome Risk: A Meta-Analysis from 34 Studies

Background

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of folate metabolic pathway which catalyzes the irreversible conversion of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. 5-methyltetrahydrofolate donates methyl group for the methylation of homocysteine to methionine. Several studies have investigated maternal MTHFR C677T polymorphism as a risk factor for DS, but the results were controversial and inconclusive. To come into a conclusive estimate, authors performed a meta-analysis.

Aim

A meta-analysis of published case control studies was performed to investigate the association between maternal MTHFR C677T polymorphism and Down syndrome.

Methods

PubMed, Google Scholar, Elsevier, Springer Link databases were searched to select the eligible case control studies using appropriate keywords. The pooled odds ratio (OR) with 95%confidence interval were calculated for risk assessment.

Results

Thirty four studies with 3,098 DS case mothers and 4,852 control mothers were included in the present meta-analysis. The pooled OR was estimated under five genetic models and significant association was found between maternal MTHFR 677C>T polymorphism and Down syndrome under four genetic models except recessive model (for T vs. C, OR = 1.26, 95% CI = 1.09–1.46, p = 0.001; for TT vs. CC, OR = 1.49, 95% CI = 1.13–1.97, p = 0.008; for CT vs. CC, OR = 1.29, 95% CI = 1.10–1.51, p = 0.001; for TT+CT vs. CC, OR = 1.35, 95% CI = 1.13–1.60, p = 0.0008; for TT vs. CT+CC, OR = 0.76, 95% CI = 0.60–0.94, p = 0.01).

Conclusion

The results of the present meta-analysis support that maternal MTHFR C677T polymorphism is a risk factor for DS- affected pregnancy.     

Methylenetetrahydrofolate Reductase C677T Polymorphism and Susceptibility to Cervical Cancer and Cervical Intraepithelial Neoplasia: A Meta-Analysis

Background

A number of studies have explored the association between methyl enetetrahydrofolate reductase (MTHFR) C677T polymorphism and susceptibility to cervical cancer and cervical intraepithelial neoplasia (CIN). However, results remained controversial. To address this gap, we decided to conduct a meta-analysis of all available published studies.

Methods

Electronic literature searches of the PubMed, EmBase and Medline databases were performed up to April 30, 2012. Fixed-effects or random-effects model was used to calculate the pooled ORs for different genetic models.

Results

A total of 12 case-control studies were ultimately identified. No statistical correlation was found between C677T variants and cervical cancer for the overall population. However, subgroup analyses on the White women pointed to a significant protective effect for individuals heterozygous or homozygous for the T-allele (for CT vs. CC: OR = 0.72, 95% CI 0.59–0.88; for TT vs. CC: OR = 0.69, 95% CI = 0.49–0.97; for CT+TT vs. CC: OR = 0.71, 95% CI 0.59–0.86). C677T variants were associated with neither combined nor stratified CIN among the overall population.

Conclusions

This meta-analysis suggests that White women with mutant C677T genotypes might have a lower risk of cervical cancer, yet lacking enough statistical robustness. Further investigations are needed to get more insight into the role of this polymorphism in cervical carcinogenesis.     

Methylenetetrahydrofolate Reductase C677T Polymorphism and Type 2 Diabetes Mellitus in Chinese Population: A Meta-Analysis of 29 Case-Control Studies

Background

Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, had significant effects on the homocysteine levels. The common functional MTHFR C677T polymorphism had been extensively researched. Several studies had evaluated the relationship between MTHFR C677T polymorphism and type 2 diabetes mellitus (T2DM), but the results were still controversial in the Chinese Han population. This meta-analysis was conducted to evaluate the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population.

Methods

We searched the relevant studies in multiple electronic databases, which published up to December 2013. We reviewed and extracted data from all the included studies on the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The odds ratios (ORs) and their 95% confidence intervals (95%CIs) were used to evaluate the relationship. Fixed-effects and random-effects meta-analysis were used to pool ORs by the heterogeneity. Publication bias and sensitivity analysis were also examined.

Results

29 studies were finally included in our meta-analysis, which contained 4656 individuals with T2DM and 2127 healthy controls. There was a significant relationship between MTHFR C677T polymorphism and T2DM under dominant (OR: 1.70, 95% CI: 1.42–2.02), recessive (OR: 1.48, 95% CI: 1.21–1.80), homozygous (OR: 1.89, 95% CI: 1.47–2.42), heterozygous (OR: 1.58, 95% CI: 1.33–1.87), and additive (OR: 1.46, 95% CI: 1.28–1.68) genetic model in a random-effects model. Subgroup analysis also reached similar results. Sensitivity analysis indicated that the overall result were dependable.

Conclusions

There was a significant relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The results of our meta-analysis suggested that MTHFR 677T allele might be a risk genetic factor of T2DM in the Chinese Han population.     

5, 10-Methylenetetrahydrofolate reductase (MTHFR) 677 C --> T genetic polymorphism in 228 Croatian volunteers

5, 10-Methylenetetrahydrofolate Reductase (MTHFR) is one of the key enzymes in the metabolism of homocysteine, where it catalyses its remethylation. The autosomal recessive bp 677 C --> T mutation in the MTHFR gene leads to the substitution of valine for alanine. Individuals who are homozygous for this C677T mutation exhibit a decreased specific activity and increased thermolability of this enzyme. This leads to increased plasma levels of homocysteine, which is a known risk factor for atherosclerosis and various manifestations of the atherosclerotic disease. The aim of this study was to find out the distribution and frequency of this mutation in the general Croatian population. A group of 228 volunteers (175 males and 53 females) has been analyzed for the MTHFR polymorphism, which revealed the following distribution: 105 (46.05%) individuals were without mutation (C/C), 102 (44.74%) were heterozygous (C/T) and 21 (9.21%) homozygous (T/T). These findings are within the results of studies on other European populations.     

Melanopsin Gene Polymorphism I394T Is Associated with Pupillary Light Responses in a Dose-Dependent Manner

Background

Melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) play an important role in non-image forming responses to light, such as circadian photoentrainment, light-induced melatonin suppression, and pupillary light response. Although it is known that there are some single nucleotide polymorphisms (SNPs) in the melanopsin (OPN4) gene in humans, the associations of the SNPs with non-image forming responses to light remains unclear. In the present study, we examined the associations of melanopsin gene polymorphisms with pupillary light response.

Methods

Japanese university students (mean age: 21.0±1.7 years) with the genotypes of TT (n = 38), TC (n = 28) and CC (n = 7) at rs1079610 (I394T) located in the coding region participated in the present study. They were matched by age and sex ratio. Dark-adapted pupil size (<1 lx) was first measured. Then steady-state pupil size was measured during exposure to five lighting conditions (10 lx, 100 lx, 1000 lx, 3000 lx, 6000 lx in the vertical direction at eye level).

Results

Significant interaction between the genotype of I394T (TT versus TC+CC) and luminance levels was found in pupil size. Under high illuminance levels (1000 lx, 3000 lx and 6000 lx), pupil sizes in subjects with the C allele were significantly smaller than those in subjects with the TT genotype. On the other hand, pupil size in subjects with the C allele under low illuminance (<1 lx) was significantly larger than that in subjects with the TT genotype. Percentages of pupil constriction under high illuminance levels were significantly greater in subjects with the C allele than in subjects with the TT genotype.

Conclusions

Human melanopsin gene polymorphism I394T interacted with irradiance in association with pupil size. This is the first evidence suggesting a functional connection between melanopsin gene polymorphism and pupillary light response as an index of non-image forming response to light.     

A Single Nucleotide Polymorphism within DUSP9 Is Associated with Susceptibility to Type 2 Diabetes in a Japanese Population

Aims

The DUSP9 locus on chromosome X was identified as a susceptibility locus for type 2 diabetes in a meta-analysis of European genome-wide association studies (GWAS), and GWAS in South Asian populations identified 6 additional single nucleotide polymorphism (SNP) loci for type 2 diabetes. However, the association of these loci with type 2 diabetes have not been examined in the Japanese. We performed a replication study to investigate the association of these 7 susceptibility loci with type 2 diabetes in the Japanese population.

Methods

We genotyped 11,319 Japanese participants (8,318 with type 2 diabetes and 3,001 controls) for each of the 7 SNPs–rs5945326 near DUSP9, rs3923113 near GRB14, rs16861329 in ST6GAL1, rs1802295 in VPS26A, rs7178572 in HMG20A, rs2028299 near AP3S2, and rs4812829 in HNF4A–and examined the association of each of these 7 SNPs with type 2 diabetes by using logistic regression analysis.

Results

All SNPs had the same direction of effect (odds ratio [OR]>1.0) as in the original reports. One SNP, rs5945326 near DUSP9, was significantly associated with type 2 diabetes at a genome-wide significance level (p = 2.21×10⁻⁸; OR 1.39, 95% confidence interval [CI]: 1.24−1.56). The 6 SNPs derived from South Asian GWAS were not significantly associated with type 2 diabetes in the Japanese population by themselves (p≥0.007). However, a genetic risk score constructed from 6 South Asian GWAS derived SNPs was significantly associated with Japanese type 2 diabetes (p = 8.69×10⁻⁴, OR  = 1.06. 95% CI; 1.03−1.10).

Conclusions/interpretation

These results indicate that the DUSP9 locus is a common susceptibility locus for type 2 diabetes across different ethnicities, and 6 loci identified in South Asian GWAS also have significant effect on susceptibility to Japanese type 2 diabetes.     

Antiretroviral Therapy,Especially Efavirenz,Is Associated with Low Bone Mineral Density in HIV-Infected South Africans

Purpose

We determined the prevalence and correlates of low bone mineral density (BMD) in HIV-infected South Africans as there is a paucity of such data from Africa.

Methods

BMD and serum 25-hydroxyvitamin D were measured in HIV-positive participants on antiretroviral therapy (ART) and in those not yet on ART (ART-naïve).

Results

We enrolled 444 participants [median age 35(IQR: 30, 40) years; 77% women]. BMD was low (z score <-2SD) in 17% and 5% of participants at the lumbar spine and total hip, respectively. Total hip [0.909 (SD 0.123) vs 0.956 (SD 0.124) g/cm², p = 0.0001] and neck of femur BMD [0.796 (SD 0.130) vs 0.844 (SD 0.120) g/cm², p = 0.0001] were lower in the ART, compared to the ART-naïve group. Vitamin D deficiency was present in 15% of participants and was associated with efavirenz use [adjusted OR 2.04 (95% CI 1.01 to 4.13)]. In a multivariate linear regression, exposure to efavirenz or lopinavir-based ART was associated with lower total hip BMD, whereas higher weight, being male and higher vitamin D concentration were associated with higher total hip BMD (adjusted R² = 0.28). Age, weight, sex, and the use of efavirenz-based ART were independently associated with lumbar spine BMD (adjusted R² = 0.13).

Conclusions

Vitamin D status, use of efavirenz or lopinavir/ritonavir, weight, age and sex are significantly associated with lower BMD in this young cohort of HIV-infected South Africans.     

Investigation of MTHFR C677T Gene Polymorphism, Biochemical and Clinical Parameters in Turkish Migraine Patients: Association with Allodynia and Fatigue

We investigated whether there is any relationship between biochemical and clinical parameters of migraine and methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism, associated with the migraine subtypes, symptoms, and gender. A total of 150 migraine patients with and without aura (MA and MO) and 107 non-sufferers were included in the study. Biochemical and clinical parameters were measured and genetic analysis was performed. The MTFHR C677T genotype was significantly higher in the migraine group (p = 0.000). The CT genotype frequency of individuals with a family history of migraine was significantly higher (p = 0.025). This genotype frequency was higher in patients who suffer from compression, allodynia, fatigue, and sleeplessness (p = 0.027, 0.023, 0.006, and 0.05, respectively). Homocysteine and total cholesterol levels were significantly higher in the migraine group than the control group (p = 0.007 and 0.010, respectively). However, the other biochemical and clinical parameters did not differ from each other (p > 0.05), with only attack frequency being significantly higher in the MO group (p = 0.005). While the folate and HDL levels were significantly higher in females (p = 0.001 and 0.000, respectively), the homocysteine and triglyceride levels were significantly higher in males (p = 0.000 for each one). BMIs were significantly lower in the control than the migraine group (p = 0.021); however, an association between the C677T variant and BMI was not found (p = 0.787) in the migraine group. An association between the MTHFR C667T polymorphism and migraine susceptibility was found. Additional studies including genetic, clinic, and biochemical parameters should be conducted to better understand the disease.     

The GADD45A (1506T>C) Polymorphism Is Associated with Ovarian Cancer Susceptibility and Prognosis

GADD45A (growth arrest and DNA damage 45 A) is the first stress-inducible gene identified to be a target of p53. However, no studies to date have assessed variants of the GADD45 gene and their potential relationship to tumor susceptibility. We investigated the association of the GADD45A (1506T>C) polymorphism with ovarian cancer development in 258 ovarian cancer patients and 332 age-matched healthy women as controls using sequence analysis. We found a statistically significant difference in the GADD45A (1506T>C) genotype distributions between the case and control groups (TT vs. TC vs. CC, P = 0.0021) and found that variant 1506T>C was significantly associated with an increased risk of ovarian cancer (P<0.001, OR = 1.71, 95% CI [1.28–2.29]). We observed a statistically significant effect between tumor histology (P = 0.032) and CA125 status (P = 0.021). Carrying the C allele (TC+CC) was associated with an increased risk of positive CA125 (OR = 3.20, 95% CI [1.15–8.71). Carrying the T allele (TT+TC) showed a significant correlation with both higher GADD45A mRNA expression and longer ovarian cancer RFS (relapse-free survival) and OS (overall survival). We are the first group to demonstrate that the GADD45A (1506T>C) polymorphism is associated with ovarian cancer susceptibility and prognosis. These data suggest that GADD45A (1506T>C) is a new tumor susceptibility gene and could be a useful molecular marker for assessing ovarian cancer risk and for predicting ovarian cancer patient prognosis.     

利用LightCycler研究食管鳞状细胞癌与MTHFR C677T多态性的关系

亚甲基四氢叶酸还原酶(MTHFR)在叶酸代谢中起重要作用.MTHFR基因第677位核苷酸的多态性（C→T）能影响其酶活性并与肿瘤易感性有关.为比较中国北方人群MTHFR C677T多态性与食管鳞状细胞癌（ESCC）易感性之间的关系, 通过高速实时聚合酶链反应（real-time PCR）和解链曲线（melting curve）方法分析了189名ESCC患者和141名健康对照的MTHFR C677T多态性位点的基因型.结果显示,健康对照组的MTHFR C/C（纯合野生）、C/T和T/T（纯合突变）基因型的频率分别为17.7%、38.3%和44.0%.ESCC患者的T/T基因型频率（42.3%）与健康对照组无显著差异（χ²=0.089, P＞0.05）,其C/T基因型频率（49.2%）仅略高于对照组（χ²＝3.890, P＜0.05）,而患者组的C/C基因型频率(8.5%)显著低于健康对照组(17.7%) (χ²=6.37, P=0.012).与C/T和T/T基因型相比,C/C基因型可显著降低ESCC的发病风险(相对风险度的比值比（OR）=0.43, 95%可信区间（CI）=0.22～0.84),在吸烟者和有上消化道肿瘤家族史的患者中这一倾向更加明显.研究提示,在中国北方人群中, MTHFR C677T纯合野生基因型对ESCC的发病起保护作用.     

组织蛋白酶D基因C224T多态与散发阿尔茨海默氏病的关联研究

组织蛋白酶D（Cathepsin D）是一种细胞核内体/溶酶体内的门冬酰胺蛋白酶。它有可能通过剪切淀粉样前体蛋白参与阿尔茨海默氏病（Alzheimer’s disease, AD）相关的神经退化。在以德国人为对象中的研究显示组织蛋白酶D基因（CTSD）C224T多态与AD发病风险紧密相关。然而,此结果未能在另一些群体中得到重复。为此,我们通过聚合酶链反应-限制性片段长度多态性方法分析了CTSD基因C224T多态性和载脂蛋白E（apolipoprotein E, ApoE）基因多态性在成都地区汉族老年人中的分布,探讨了CTSD C224T多态与散发AD的相关性。结果发现CTSD基因C224T多态分布在病例组与对照组之间没有显著性差异,提示成都地区汉族人群中CTSD基因C224T多态与散发AD不具有关联;但比值比的比较提示CTSD等位基因T和ApoEε4有弱的协同作用。Abstract: Cathepsin D is the major lysosomal/endosomal aspartic protease and exhibits β- and γ-secretase-like activity in vitro. Data from German suggest that the C224T polymorphism in the Cathepsin D gene (CTSD) exon 2 is strongly associated with the risk for Alzheimer’s disease (AD).Meanwhile other studies have not been able to replicate the result. It’s necessary to determine the genotype of the polymorphism in CTSD in Chinese sporadic AD patients and age-matched controls with normal cognition and examine possible association of the polymorphism with the disease. We find no strong evidence of association between the CTSD C224T polymorphism and Chinese sporadic AD. Whereas there may be a weak synergistic interaction between ApoE ε4 and CTSD T allele.     

IL-4 Haplotype -590T, -34T and Intron-3 VNTR R2 Is Associated with Reduced Malaria Risk among Ancestral Indian Tribal Populations

Background

Interleukin 4 (IL-4) is an anti-inflammatory cytokine, which regulates balance between T_H1 and T_H2 immune response, immunoglobulin class switching and humoral immunity. Polymorphisms in this gene have been reported to affect the risk of infectious and autoimmune diseases.

Methods

We have analyzed three regulatory IL-4 polymorphisms; -590C>T, -34C>T and 70 bp intron-3 VNTR, in 4216 individuals; including: (1) 430 ethnically matched case-control groups (173 severe malaria, 101 mild malaria and 156 asymptomatic); (2) 3452 individuals from 76 linguistically and geographically distinct endogamous populations of India, and (3) 334 individuals with different ancestry from outside India (84 Brazilian, 104 Syrian, and 146 Vietnamese).

Results

The -590T, -34T and intron-3 VNTR R2 alleles were found to be associated with reduced malaria risk (P<0.001 for -590C>T and -34C>T, and P = 0.003 for VNTR). These three alleles were in strong LD (r²>0.75) and the TTR2 (-590T, -34T and intron-3 VNTR R2) haplotype appeared to be a susceptibility factor for malaria (P = 0.009, OR = 0.552, 95% CI = 0.356 –0.854). Allele and genotype frequencies differ significantly between caste, nomadic, tribe and ancestral tribal populations (ATP). The distribution of protective haplotype TTR2 was found to be significant (χ² ₃ = 182.95, p-value <0.001), which is highest in ATP (40.5%); intermediate in tribes (33%); and lowest in caste (17.8%) and nomadic (21.6%).

Conclusions

Our study suggests that the IL-4 polymorphisms regulate host susceptibility to malaria and disease progression. TTR2 haplotype, which gives protection against malaria, is high among ATPs. Since they inhabited in isolation and mainly practice hunter-gatherer lifestyles and exposed to various parasites, IL-4 TTR2 haplotype might be under positive selection.     

Vitamin D Insufficiency Is Common in Ugandan Children and Is Associated with Severe Malaria

Vitamin D plays an increasingly recognized role in the innate and adaptive immune response to infection. Based on demonstrated roles in up-regulating innate immunity, decreasing inflammation, and reducing the severity of disease in illnesses such as tuberculosis and influenza, we hypothesized that poor vitamin D status would be associated with severe malaria. We measured 25-hydroxyvitamin D [25(OH)D] by immunoassay in a sample of Ugandan children aged 18 months –12 years with severe malaria (cerebral malaria or severe malarial anemia, n = 40) and in healthy community children (n = 20). Ninety-five percent of children with severe malaria (n = 38) and 80% of control children (n = 16) were vitamin D-insufficient [plasma 25(OH)D <30 ng/mL]. Mean plasma 25(OH)D levels were significantly lower in children with severe malaria than in community children (21.2 vs. 25.3 ng/mL, p = 0.03). Logistic regression revealed that for every 1 ng/mL increase in plasma 25(OH)D, the odds of having severe malaria declined by 9% [OR = 0.91 (95% CI: 0.84, 1.0)]. These preliminary results suggest that vitamin D insufficiency may play a role in the development of severe malaria. Further prospective studies in larger cohorts are indicated to confirm the relationship of vitamin D levels to severity of malaria infection and to investigate causality.