Heat-shock protein gene is not associated with type-1 diabetes in African Americans

The polymorphism at the heat-shock protein gene was reported to be associated with type-1 diabetes in Caucasians but not in the Japanese. We report in this study the association between HSP70-1 alleles and type-1 diabetes in 30 unrelated African-American patients and 96 ethnically matched controls from the Washington, DC area. The polymorphic variation (A-C transversion) at position -110 in the HSP70-1 promoter region was amplified using the polymerase chain reaction. No significant differences between patients and controls were detected. These data suggest that in African Americans, HSP70-1 polymorphism is not associated with type-1 diabetes and is similar to findings in Japanese patients. The difference between results from this study and that of Caucasians may be due to population differences in genetic polymorphism or to linkage disequilibrium of HSP70-1 with human leukocyte antigen class-II alleles associated with type-1 diabetes susceptibility genes.     

Matrix metalloproteinase-3 gene polymorphisms are associated with ischemic stroke

Stroke is a heterogeneous disease caused by different pathogenic mechanisms. Several candidate genes for stroke have been proposed, but few have been replicated. Matrix metalloproteinases (MMPs) are expressed following stroke. We investigated the association of single nucleotide polymorphisms (SNPs) of the MMP3 gene with stroke in the Korean population. This study included 186 stroke patients [116 ischemic stroke (IS) and 70 intracerebral hemorrhage (ICH)] and 668 age-matched control subjects (267 for IS and 401 for ICH). Three SNPs [rs520540 (Ala362Ala), rs602128 (Asp96Asp), and rs679620 (Lys45Glu)] in the coding region of MMP3 were selected and genotyped by direct sequencing. HelixTree, SNPAnalyzer, SNPStats, and Haploview version 4.2 were used to analyze genetic data. Multiple logistic regression models (codominant, dominant, and recessive models) were conducted to evaluate odds ratio, 95% confidence interval, and P value. Three SNPs in the MMP3 gene were significantly associated with IS (P<0.05). The genotype distribution of 3 SNPs differed between the IS and control subjects. However, there was no association of the SNPs between the ICH and control. In analysis of gender, 3 SNPs were also associated with IS in female group (P<0.05). These SNPs remained significantly associated with IS after the Bonferroni correction for multiple testing (P(c)<0.05). Haplotype analysis revealed that no haplotypes were associated with IS or ICH. Overall, the results of our study demonstrate an association of the MMP3 gene with development of IS, and no association of MMP3 with ICH.     

CA repeat allele polymorphism in the first intron of the human interferon-gamma gene is associated with lung allograft fibrosis.

Interferon-gamma (IFN-gamma) is an inflammatory cytokine that has been implicated in the development of fibrosis in inflamed tissues. In this study we have analysed the association between genetically-determined high IFN-gamma production and development of fibrosis in lung transplants. The human IFN-gamma gene has a variable length CA repeat in the first intron. Our previous study showed that polymorphism of this microsatellite is associated with individual variation in the levels of IFN-gamma production. In vitro production of IFN-gamma showed significant correlation with presence of allele #2 (p < 0.01). In this study allele #2 was found to be associated with allograft fibrosis defined by transbronchial biopsy. An analysis of two groups of lung transplant recipients showed a significant increase in the frequency of allele #2 in the group which developed fibrosis after transplantation compared to the group that did not (p < 0.005). We postulate that the production of IFN-gamma, which is under genetic control, can influence the development of fibrosis in lung allografts.     

The 894T allele of endothelial nitric oxide synthase gene is related to left ventricular mass in African Americans with high-normal blood pressure

BACKGROUND AND OBJECTIVES: The 894T allele in exon 7 of the endothelial nitric oxide synthase (eNOS) gene has been inconsistently associated with hypertension in different racial groups. Because high-normal blood pressure (BP) confers an increased risk for the development of hypertension and other cardiovascular disorders, including left ventricular hypertrophy (LVH), we tested the hypothesis that the allelic variation (894T) in the eNOS gene would directly correlate with alterations in LV mass (LVM) in individuals with high-normal BP. METHODS: Genotype distribution of G894T was compared between 20 African Americans (10 females/10 males) with high-normal BP (systolic BP of 130-139 and/or diastolic BP of 85-89 mmHg) and 64 counterparts (37 females/27 males) with normal BP (<130/85 mmHg). Echocardiographic LVM was calculated (Devereux formula) and indexed to body surface area to define the presence of LVH (LVMI >134/110 g/m2 for men/women). RESULTS: For the entire group, the 894T allelic frequencies (15, 48%) and G894T genotype distributions were consistent with the Hardy-Weinberg equilibrium expectations (estimated disequilibrium coefficient = 0.0118, P=0.40). LVMI was significantly higher in homozygous carriers (TT) of the rare 894T allele (n = 3 females/0 males) than in heterozygous GT (n = 13 females/7 males) and individuals bearing the GG (n=34 females/27 males) variant (124 +/- 70 vs. 82 +/- 24 and 82 +/- 19 g/m2, respectively, P < 0.05). The observed relationship between eNOS 894T allele and LVMI was restricted to individuals with high-normal BP (r = 0.94, P = 0.03) but not in those with normal BP (r = 0.39, P =0.64), by analysis of variance (ANOVA) after adjusting for age, gender, body mass index, smoking and systolic BP. CONCLUSION: These findings, not previously described, provide important preliminary evidence to suggest an increased susceptibility to LVH in African Americans who carry the 894T variant of the eNOS gene and have high-normal blood pressure.     

Apolipoprotein epsilon4 allele frequency in young Africans of Ugandan descent versus African Americans

Through its role in lipid metabolism, Apolipoprotein epsilon4 (ApoE4) may affect "brain repair" in stroke, brain hemorrhage, Alzheimer's disease, and other brain injury syndromes for which African Americans may have greater morbidity and mortality. Cross-cultural evaluations of these and other genetic factors may provide insight on possible ethnic differences in risk of morbidity to acute central nervous system (CNS) injury and chronic neurodegenerative processes. As an initial step toward expanding knowledge of ApoE allele frequencies for persons of African descent, we compared ApoE genotype of a group of 70 young Ugandans to 59 (subset of a larger group of 342 African Americans of all ages) age-matched African Americans and to published frequencies for Caucasians and Asians. We found that the ApoE4 and epsilon2 alleles are more frequent in Ugandans (U) than Caucasians (C) or Asians (A) with corresponding alleles showing significant elevations of epsilon2 (U 15.71%, C 8.40%, A 4.20%) and 14 (U 25%, C 13.70%, A 8.90%) (p < .001). Comparing the differences between Ugandans and age-appropriate African Americans (AA) was not statically significant, but this outcome may be due to small sample size. These results provide the only published ApoE frequencies for Ugandans and the complete set of data provides the largest published community group of ApoE frequencies for African Americans.     

The natural resistance-associated macrophage protein gene in African Americans with sarcoidosis

The histologic and clinical similarities between tuberculosis and sarcoidosis suggest a shared underlying pathophysiology. Human natural resistance-associated macrophage protein (NRAMP1), which is closely related to the mouse gene, has been associated with susceptibility to tuberculosis in some human populations. Given the importance of the Nramp1 gene in animal models of granulomatous disorders, the association with human tuberculosis, and the possible role of NRAMP1 in macrophage activation and function, we hypothesized that human NRAMP1 plays a role in susceptibility to sarcoidosis. We analyzed several NRAMP1 gene polymorphisms in a case-control study of 157 African American patients with sarcoidosis and 111 African American control subjects. Our results, in contrast to those in tuberculosis patients, showed that the less common genotypes were found more often in control subjects than in case patients (odds ratio, 0.48; 95% confidence interval, 0.28-0.81). In particular, one polymorphism, a (CA)(n) repeat in the immediate 5' region of the gene, was found to have a protective effect (P = 0. 014). Whereas NRAMP1 polymorphisms have been associated with increased susceptibility to tuberculosis, our results suggest that at least one NRAMP1 polymorphism may decrease susceptibility in sarcoidosis.     

Autoimmune cholangitis in NOD.c3c4 mice is associated with cholangiocyte-specific Fas antigen deficiency

A major handicap in understanding the pathogenesis of autoimmune cholangitis has been the absence of an informative mouse model. Recently, autoimmune cholangitis, with several features similar to PBC, has been described in NOD.c3c4 mice, including anti-mitochondrial antibodies, lymphocytic portal tract infiltrates, biliary destruction and the adoptive transfer of disease to na?ve recipients using liver-derived lymphocytes. A unique feature, and a characteristic quite distinct from human PBC, is the presence of bile cyst formation. We have addressed the issue of cysts in NOD.c3c4 mice by performing comprehensive microarray analysis using cholangiocytes from NOD.c3c4 mice compared to NOD controls. Several key differences in gene expression were noted in NOD.c3c4 cholangiocytes. First, there was consistent impairment in the expression of Fas antigen (CD95). Second, cholangiocytes were PCNA positive but TUNEL negative, suggesting an absence of apoptosis despite abnormal proliferation. In conclusion, we propose that autoimmune cholangitis develops in NOD.c3c4 mice secondary to impaired biliary cell apoptosis with exposure of mitochondrial antigens, loss of tolerance and subsequent development of multi-lineage anti-mitochondrial responses.     

3'UTR C2370A allele of the IL-23 receptor gene is associated with relapsing-remitting multiple sclerosis

The interleukin (IL) -23/IL-17 cytokine axis has been suggested to play an important role in the development of several autoimmune diseases including multiple sclerosis. Here, we compared the prevalence of C2370A single nucleotide polymorphism (SNP) in the 3' untranslated region (3'UTR) of the IL-23 receptor (IL23R) between 223 patients with relapsing-remitting multiple sclerosis (RRMS) and 200 healthy controls. The A2370A genotype was significantly over-represented among patients with RRMS (10.8%) and RRMS exhibiting oligoclonal bands in the cerebrospinal fluid (12.9%) when compared to healthy subjects (5.50%). Multiple regression analysis revealed that presence of AA genotype provides a two-fold risk for the development of multiple sclerosis (OR=2.072, 95% CI: 0.988-4.347, p<0.05). These data indicate that IL23R represents a novel shared susceptibility gene as its association with inflammatory bowel disease (IBD) has recently been verified.     

Genetic variation at immunoglobulin kappa locus is associated with hepatitis C-treatment-induced viral clearance in African Americans

Host genetic factors, especially genes of the immune system, are thought to contribute to the racial differences in response rates to therapy for hepatitis C virus (HCV) infection. The aim of the present investigation was to determine whether immunoglobulin gamma heavy chain marker (GM) and kappa light chain marker (KM) -were associated with sustained viral response (SVR) in patients treated with peginterferon-α-2a and ribavirin. DNA samples from 319 subjects with genotype-1 HCV infections were allotyped for alleles at four GM loci: GM3/GM17, GM23+/GM23-, GM5/GM21, GM6+/GM6- and the KM locus: KM1/KM3, using molecular methods. Noncarriage of KM1 allele, i.e., KM3 homozygosity, was associated with higher SVR in African Americans (odds ratio = 2.50, 95% confidence interval = 1.12-5.60). Consistent with this finding, the HCV RNA level in KM1 noncarriers was significantly (p = 0.013) lower than in carriers of this allele. Thus, the KM3 allele may be a marker for higher SVR in African Americans.     

基质金属蛋白酶-3基因多态性与脑卒中亚型的相关性

目的 探讨中国北方汉族人群基质金属蛋白酶-3(matrix metalloproteinase-3,MMP-3)基因多态性与缺血性脑卒中(ischemic stroke,IS)亚型的相关性.方法 应用病例对照研究,选取289例急性缺血性脑卒中患者(发病≤3d)和175名同期健康体检者.卒中组按急性卒中治疗低分子肝素试验病因分型法分为大动脉粥样硬化性(large artery atherosclerotic,LAA)脑卒中185例,小动脉闭塞性(small artery occlusion,SAO)脑卒中104例.选取MMP-3基因rs3025058(-11715A/6A),rs522616(-709A/G)及rs679620(133A/G)3个常见单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点,应用聚合酶链反应限制性片段长度多态性或直接测序法对MMP-3基因3个SNP位点进行基因分型.结果 3个位点存在不完全连锁不平衡,且基因多态性均与LAA型脑卒中相关(P＜0.05).在显性模型中,rs3025058位点5A5A+5A6A基因型携带者患LAA型脑卒中的风险是6A6A基因型携带者的1.72倍(P=0.017,OR=1.72,95％CI:1.10～2.69);rs522616位点GG+ AG基因型携带者患LAA型脑卒中的风险是AA基因型携带者的0.52倍(P=0.005,OR=0.52,95％CI:0.33～0.82);rs679620位点AA+ GA基因型携带者患LAA型脑卒中的风险是AA基因型携带者的1.55倍(P=0.042,OR=1.55,95％CI:1.01～2.37).但是,3个SNPs基因型和等位基因频率在对照组与SAO型脑卒中之间差异无统计学意义(P＞0.05).另外,LAA组5A-A-A及6A-A-A单倍型高于对照组,差异有统计学意义(P＜0.05),而6A-G-G单倍型显著低于对照组(P＜0.01).结论 MMP-3血清水平在LAA型脑卒中急性期增高明显,SAO型脑卒中次之;中国北方汉族人群MMP-3基因rs3025058,rs522616及rs679620多态性可能与LAA型脑卒中易感性相关.     

A single nucleotide polymorphism (A --> G) in intron 3 of IFNgamma gene is associated with asthma

Interferon-gamma (IFNgamma) is located on chromosome 12, and a number of studies have detected very strong linkage signals around this gene and asthma. The aim of this study was to analyze the association of a (CA)n repeat in intron 1 and six single nucleotide polymorphisms (((rs2069705, T/C) (promoter)), ((rs1861494, A/G), (rs1861493, T/C), (rs2069718, C/T) (intron 3)), ((rs2069727, A/G) and (rs2069728, G/A) (3' untranslated region))) spanning the whole gene with asthma. We report here the association of rs1861494 A/G with atopic asthma in a case-control cohort (n=189 and n=270 cases and controls, respectively) (P=0.0006), which was replicated (P=0.006) in a family study (n=137) as well. Allele G was found to be negatively associated (odds ratio=0.50, 95% confidence interval, P=0.0006). A five-locus haplotype also showed significant association with asthma in the case-control (P=0.002) and the family studies (P=0.0004). In our three-locus sliding window haplotypic analysis, we found the (CA)n repeat, rs1861494 A/G and rs2069718 C/T to be of high priority (P=0.0003). Using electrophoretic mobility shift assay, we provide evidence that the alleles of rs1861494 A/G have differential affinity to bind to putative nuclear factor(s). In conclusion, we report for the first time association of rs1861494 A/G polymorphism with asthma, which may regulate the IFNgamma levels and, hence, modulate asthma pathogenesis.     

(CCTTT)n repeat polymorphism in the NOS2 gene promoter is associated with atopy.

BACKGROUND: Several studies have shown that nitric oxide (NO) plays a role in the regulation of the T(H)1/T(H)2 balance, indicating the potential for NO to contribute to the development of atopy and several other allergic diseases, including bronchial asthma. NO synthase 2 (NOS2) is critically involved in the synthesis of NO during several inflammatory states, and the gene encoding NOS2 is located at chromosome 17q11.2-q12, where 2 genome scans have identified a candidate locus for atopy and asthma. OBJECTIVE: The 14-repeat allele of the (CCTTT)(n) repeat polymorphism in the NOS2 promoter region is a powerful enhancer of promoter activity in reporter constructs in vitro. We tested whether this potentially functional allele in the NOS2 gene influences the development of atopy and asthma. METHODS: We studied a total of 497 unrelated Japanese subjects (141 nonatopic healthy controls, 102 atopic healthy controls, 56 nonatopic asthmatic subjects, and 198 atopic asthmatic subjects). The odds ratio (OR) was calculated for atopy and asthma in carriers of the 14-repeat allele through use of logistic regression models. Atopy was defined as a positive specific IgE level to at least 1 of 10 common inhaled allergens. RESULTS: The 14-repeat allele was inversely associated with atopy (OR = 0.42, P < .01). The association remained significant when the model was controlled for asthmatic status (OR = 0.36, P < .01). This allele, however, was associated neither with the development of asthma nor with total serum IgE levels. CONCLUSION: Our findings suggest that the (CCTTT)(n) repeat polymorphism in the promoter of the NOS2 gene that affects promoter activity is a risk factor for the development of atopy, and this genetic effect seems independent of asthma.     

An increased frequency of the 5A allele in the promoter region of the MMP3 gene is associated with abdominal aortic aneurysms

Matrix metalloproteinase 3 (MMP3), is over expressed in the wall of abdominal aortic aneurysms (AAA), while inactivation of the gene expressing this enzyme is associated with reduced aneurysm formation in an experimental model. The 5A allele of the 5A/6A polymorphism in the promoter region of the MMP3 gene is associated with enhanced MMP3 expression. This study aimed to determine whether the presence of the 5A allele in the MMP3 promoter is a risk factor for AAA, and if this allele is associated with an increased expression of MMP3 in the aneurysm wall. We compared the frequencies of the 5A and 6A alleles in AAA (n = 405), aortic occlusive disease (AOD) (n = 123) and controls (n = 405). The 5A allele frequency was higher in AAA compared with controls (odds ratio - OR 1.32, P = 0.005) and AOD (OR 1.684, P = 0.0004), but was similar in AOD compared to controls (OR 0.78, P = 0.1). The ORs of the 5A/6A and the 5A/5A genotypes were 1.35 and 1.79, compared with 6A homozygotes. Although wall from 5A homozygotes contained 17% more MMP3 mRNA than homozygotes (P = 0.049) the significance of this was lost when adjusted for age and sex (P = 0.069), and size (P = 0.30). Wall from 5A homozygotes did however contain over 45% more MMP3 protein than heterozygotes (P = 0.009 when corrected for age and sex and P = 0.043 when corrected for aneurysm size). It appears that an abnormality in the MMP3 gene is part of the genetic profile that predisposes to aneurysmal disease.