APOE promoter polymorphisms do not confer independent risk for Alzheimer's disease in a French population

The apolipoprotein E (APOE, gene; apoE, protein) isoforms are associated with differential risk of Alzheimer's disease (AD). An additional involvement of APOE promoter polymorphisms in AD risk has recently been suggested by several studies. Indeed, three polymorphisms of the APOE regulatory region (-219 G/T, -427 C/T and -491 A/T) have been found associated with AD even after adjustment on the apoE status. We analysed these three promoter region polymorphisms in a large French case-control study (388 AD cases and 386 controls). We found that the -427 T and -491 A alleles were associated with an increased risk of developing AD, but not the -219 G/T alleles. However, a strong linkage disequilibrium was observed between the alleles of these promoter region polymorphisms and the APOE coding region alleles. We therefore retested association after adjustment on apoE status and found that the sole association which remained significant was the association with the -427 T allele. The alpha level was equal to 0.03 (0.09 after Bonferroni correction for multiple comparisons). Analysis of promoter haplotypes also yielded non-significant results. Thus our study does not reinforce the hypothesis of an independent involvement of the APOE promoter region polymorphisms in AD risk.     

Association between promoter polymorphisms of vascular endothelial growth factor gene and sporadic Alzheimer's disease among Northern Chinese Han

Increasing evidences suggest that polymorphisms within the promoter region of the vascular endothelial growth factor (VEGF) gene may elevate the risk for Alzheimer's disease (AD). In Northern Chinese Han, we found three polymorphisms in the VEGF promoter: −2578C/A (rs699947), −2549I/D (rs35569394) and −1154G/A (rs1570360). A strong linkage disequilibrium was detected between −2578C/A and −2549I/D. After adjusting the data by gender, age and the APOE?4 status using logistic regression, the −1154G/G genotype was found to increase the risk for sporadic AD (SAD) by 1.4-folds. In the subgroup of APOE?4 non-carriers, the −1154G allele and −2549D/−1154G haplotype were observed to be significantly higher in the 279 SAD patients than in the 317 healthy individuals. The present study provides the evidence that the −1154G allele and the −2549D/−1154G haplotype may be associated with the development of SAD in the individuals without APOE?4 allele.     

Association between promoter polymorphisms in anterior pharynx-defective-1a and sporadic Alzheimer's disease in the North Chinese Han population

Amyloid β-peptide (Aβ) deposition in brain is important in the development of sporadic Alzheimer's disease (SAD) and Aβ is produced through sequential cleaving of amyloid precursor protein (APP) by β-secretase and γ-secrease. Anterior pharynx-defective-1 (APH-1) is an important subunit of the gamma-secretase complex, and its expression level was associated with the activity of γ-secrease. We hypothesized that alterations in the APH-1 promoter region might alter APH-1 expression and the activity of γ-secrease, thus be involved in the SAD process. In the present study, we sequenced APH-1a promoter region in 20 randomly selected controls and 20 SAD patients and detected two polymorphisms which were −980C/G (rs3754048) and −21C/A (rs2275780). Then, we investigated genotypes and allele of these two polymorphisms as well as apolipoprotein ?4 (APOE ?4) status in 256 SAD patients and 276 normal controls with restriction fragment length polymorphisms analysis and sequencing. Results showed the GG genotype and G allele of −980C/G polymorphism were more frequent in the SAD group than that in the controls not only in the whole subjects (genotype P = 0.038, allele P = 0.01 respectively) but also in the APOE ?4 + subjects (genotype P = 0.048, allele P = 0.016 respectively). There was no statistical difference between SAD group and controls regarding to the frequency of alleles and genotypes of −21C/A whenever before or after stratification by APOE ?4. Our results suggest that there is an association between −980C/G and the development of SAD in the Northern Han Chinese population and that allele G may interact synergistically with the APOE ?4 allele to increase the risk of SAD.     

Association between promoter polymorphisms of the nicastrin gene and sporadic Alzheimer's disease in North Chinese Han population

Increasing evidences have shown that nicastrin (NCSTN) plays a crucial role in γ-cleavage of the amyloid precursor protein (APP). Inhibition of NCSTN demonstrated an altered γ-cleavage activity, suggesting its potential implication in developing Alzheimer's disease (AD). We detected the NCSTN gene promoter region in 359 sporadic AD (SAD) patients and 331 controls and found three promoter single nucleotide polymorphisms (SNPs): −1216C/A (rs2147471), −796T/G (rs10752637) and −436C/T (rs1324738). For −1216C/A, there were significant differences in the allele and genotype frequency between AD and control subjects (allele P = 0.031, genotype P = 0.017). The allele and genotype frequencies remained significant before and after APOE?4 stratification. The −1216CC carriers increased 2-fold risk for the development of SAD compared to the carriers with −1216CA and AA genotypes (OR = 2.049, 95%CI = 1.410–2.976, P = 0.000). For −796T/G, there were significant differences in the genotype frequency between SAD and control subjects (P = 0.009). This trend is still obvious in the subjects without APOE?4 allele. The −796GG carriers might decrease the risk compared to the carriers with −796TG and TT genotypes (OR = 0.602, 95%CI = 0.393–0.932, P = 0.022). No significant difference was detected either in genotype or in allele frequencies between SAD and control for −436C/T, even after APOE?4 stratification. The haplotype −1216A/−796G may be a protective factor for SAD (OR = 0.795, 95%CI = 0.636–0.995, P = 0.045). Our investigation suggests that −1216C/A and −796T/G are probably related to the development of SAD.     

Polymorphism in genes involved in adrenergic signaling associated with Alzheimer's

To investigate the potential involvement of adrenergic signaling in Alzheimer's disease (AD) pathogenesis, we performed genetic and functional studies of genes initiating the cascade. We chose two functional single-nucleotide polymorphisms (SNPs) in the beta1-adrenergic receptor (ADRB1) and the G protein beta3 subunit (GNB3) genes, respectively, and analyzed their allelic frequencies in a case-control sample of AD. We found that the GNB3 T allele produces a significant risk for AD in individuals homozygous for the ADRB1 C allele, suggesting that the combined effect of both polymorphisms influences AD susceptibility. Interestingly, the co-expression of GNB3 T and ADRB1 C alleles, compared with GNB3 C and ADRB1 G, produced increased cAMP levels and MAPK activation following adrenergic stimulation of transfected human cell lines. Furthermore, the co-expression of these alleles also produced increases in APP expression. These data strongly indicate that the combination of GNB3 and ADRB1 polymorphisms produces AD susceptibility by changing the cell responsiveness to adrenergic stimulation, pointing to the modulation of brain adrenergic receptors as a potential target for novel AD therapeutic strategies.     

The interleukin-6 gene −572C/G promoter polymorphism modifies Alzheimer's risk in APOE ɛ4 carriers

Inflammatory response is involved in the etiopathology of Alzheimer's disease (AD). Interleukin-6 (IL-6), a pleiotropic inflammatory cytokine, was reported to be associated with both increased Aβ aggregation and the appearance of hyperphosphorylated tau in AD brain. To explore the association of genetic variants in the promoter of IL-6 gene with sporadic AD (SAD), a case–control study was conducted in a North Chinese Han population. A systematic screening of IL-6 promoter was performed using direct sequencing and two polymorphisms were obtained including −572C/G (rs1800796) and −384A/T (rs7802308). Definitive genotyping of these markers and apolipoprotein E (APOE) polymorphism were surveyed in 341 SAD patients and 421 controls. The results revealed no significant differences in the distributions of alleles or genotypes between SAD and control groups. However, there was an interaction between −572C/G and APOE genotypes (P = 0.016) using logistic analysis. In the subjects with APOE ?4, there were significant differences in the allele (P = 0.004) and genotype (P = 0.004) distributions of −572C/G polymorphism between SAD and control groups. The −572CC genotype increased risk for AD by 3.301-fold (Wald = 11.093, adjust OR = 3.301, 95% CI = 1.635–6.665, P = 0.001) compared to CG + GG genotype. The present results suggest the −572 polymorphism could modify the risk for SAD in APOE ?4 carriers.     

Association of RFC1 A80G and MTHFR C677T polymorphisms with Alzheimer's disease

We examined polymorphisms in reduced folate carrier gene (RFC1) and methylenetetrahydrofolate reductase gene (MTHFR) for association with sporadic AD (SAD) in Chinese population. Significant associations of RFC1 A80G G allele and GG genotype with SAD (p=0.008, OR=1.312, 95%CI=1.072-1.605, and p=0.042, OR=1.383, 95%CI=1.012-1.890) were found. Further stratification of total samples by APOE epsilon4 carrier status, age/age at onset and gender revealed that RFC1 A80G G allele was an APOE epsilon4-independent risk factor for late-onset AD, and it might increase the risk of AD in females. No significant associations of MTHFR C677T allele and genotype with AD were observed in total samples, but significant associations of T allele and TT genotype with AD (p=0.031, OR=1.586, 95%CI=1.042-2.414, and p=0.028, OR=2.250, 95%CI=1.074-4.712) were identified in APOE epsilon4 carrier subgroup, suggesting that MTHFR 677 T allele and APOE epsilon4 allele may synergistically act to increase AD risk. No significant effect of RFC1 G80A and MTHFR C677T polymorphisms on plasma folate and homocysteine levels was detected.     

Association between lymphotoxin beta receptor gene polymorphisms and IgA nephropathy in Korean children

Lymphotoxin beta receptor (LTBR) is essential for development and organization of the secondary lymphoid tissues. To investigate whether LTBR polymorphisms are associated with IgA nephropathy (IgAN) in Korean children, One hundred ninety nine patients with IgAN and 289 controls were recruited. Two promoter single nucleotide polymorphisms (SNPs) (rs3759333, -1387C/T and rs3759334, -1326A/G) and one coding SNP (rs2364480, Ala172Ala) in LTBR gene were selected and genotyped by direct sequencing. For analysis of data, SNPStats, SPSS 18.0, and Haploview version 4.2 were used. Multiple logistic regression models (codominant 1, codominant 2, dominant, and recessive models) were performed for odds ratio (OR), 95% confidence interval (CI), and p value. The rs3759334 was significantly associated with IgAN in codominant 1 (G/G vs. A/G, p = 0.025) and dominant (p = 0.017) models. The A alleles of rs3759334 and rs2364480 were related to risk of developing IgAN, respectively (rs3759334, p = 0.015; rs2364480, p = 0.041). Haplotypes CGC and TAA in LTBR gene were also associated with IgAN, respectively (CGC, p = 0.032 in codominant; TAA, p = 0.008 in codominant, p = 0.009 in dominant models). In conclusion, results suggest that LTBR gene polymorphisms may be associated with risk of IgAN in Korean children.     

Genetic association between matrix metalloproteinase MMP-9 and MMP-3 polymorphisms and Japanese sporadic Alzheimer's disease

Recent studies suggested that matrix metalloproteinases (MMPs) might play an important role in the pathophysiology of Alzheimer's disease (AD). MMP-9 and MMP-3 are reported to degrade amyloid beta and have several functional polymorphisms associated with other common diseases. Four common polymorphisms in each of MMP-9 and MMP-3 were examined in AD cases and normal control individuals. Common polymorphisms of MMP-9, rs3918248, rs2664538, rs2250889 and rs2274756 showed no association with risk for AD. We observed strong linkage disequilibrium (LD) between rs2664538 and rs2250889 in our Japanese samples. The polymorphisms of MMP-3; 5A/6A insertion polymorphism in the promoter, rs3025079, rs520540 and rs679620 also did not influence risk for AD. LD of the 5A/6A polymorphism with rs679620 was relatively strong. These results suggest that the common polymorphisms of MMP-9 and MMP-3 investigated here are not associated with AD.     

Association between haplotype −88G/25G in A2M with Alzheimer's disease

Alpha 2-Macroglobulin gene (A2M) has been recognized as a candidate gene for late-onset Alzheimer's disease (AD), but the association between several polymorphisms in A2M gene and risk for AD remained controversial. Moreover, little is known regarding the effects of polymorphisms in A2M promoter region on AD susceptibility. Our study aimed to detect polymorphisms in A2M promoter region, and then evaluate their relationship to sporadic AD (SAD). One single nucleotide polymorphism (−88A/G) in proximal promoter region was found by sequencing, and further analyzed with an established 25T/G polymorphism in 179 SAD patients and 179 age-gender-matched controls. Allele A in −88A/G polymorphism was more prevalent in cases, with a 1.7-folded risk for SAD (OR = 1.74, 95%CI 1.05–2.91, P = 0.031), while G allele in 25T/G was less prevalent in cases, with a 43% reduced risk for SAD (OR = 0.57, 95%CI 0.36–0.89, P = 0.013). After adjusted the effects of age, gender and APOE?4 allele status in logistic regression model, the protective effects of −88G and 25G on SAD still remained. Individuals who carried haplotype −88G/25G had a significant 44% reduced risk for SAD compared to those who did not carry (OR = 0.56, 95%CI 0.34–0.94, P = 0.027), while haplotype −88A/25T carriers had an increased risk for SAD compared to those who did not carry (OR = 1.77, 95%CI 1.06–2.96, P = 0.027). Our study supports that haplotype −88G/25G might play a protective role in the development of SAD, and the protective effects of −88G and 25G were independent of APOE?4 allele.     

海南汉族人群九个纤维蛋白原基因多态性及其与血浆纤维蛋白原水平的关系

目的 调查海南汉族健康人群αTaqⅠ和βBclⅠ、HinfⅠA／C、448G／A、βBsmA ⅠG／C、＋1689T／G、-148C／T、-249C／T、-455G／A多态性的等位基因频率及其与血浆纤维蛋白原（fibrinogen，Fg）水平的关系。方法 用比浊法测定238名健康个体的血浆Fg浓度，用PCR-限制性片段长度多态性方法及测序法分析多态性基因型，并用协方差分析比较9个位点的基因型与血浆Fg水平的关系。结果 海南汉族人群αTaqⅠ、βBclⅠ、HinfⅠA／C、C448、βBsmAⅠG／C、＋1689T／G、-148C／T、-249C／T、-455G／A稀有位点的等位基因频率分别为0．445、0．239、0．134、0．235、0．273、0．241、0．265、0．441、0．254，9个位点之间存在连锁不平衡；在总人群中，-455GA和AA基因型、-148CT和TT基因型、αTaqⅠT1T1基因型组的血浆Fg水平比野生型组高（P值均〈0．01）；在男性人群中，-455GA和AA基因型、-148CT和TT基因型、αTaqⅠT1T1、αTaqⅠT1T2基因型组的血浆Fg水平比野生型组高（P值均〈0．01）。在女性人群中，携带稀有位点A^-455、T^-148、αTaⅠT1的基因型组与野生型组之间的血浆赡水平差异无统计学意义。结论 在9个多态性位点之间存在连锁不平衡；A^-455、T^-148、αTaqⅠT1位点与血浆Fg水平增高关联，β-Fg-455G／A、-148C／T及α-TaqⅠ多态性与男性血浆Fg水平关联。     

海南汉族人群中α和β纤维蛋白原基因核苷酸多态性及其单倍型与缺血性脑卒中的关联分析

目的研究α纤维蛋白原基因的Taq Ⅰ多态性和β纤维蛋白原基因-455G／A、-249C／T、-148 C／T、＋1689T／G、βBsmA ⅠG／C、448G／A、Be／ⅠG／A、Hinf Ⅰ A／C单核苷酸多态性及其单倍型与缺血性脑卒中的关系。方法用比浊法测定160例海南籍缺血性脑卒中和130名海南籍对照个体的血浆纤维蛋白原浓度，用PCR-限制性片段长度多态法确定基因型。用EH＋程序分析核苷酸多态性的连锁不平衡关系及单倍型，用卡方检验分析病例组和对照组的等位基因频率、基因型频率及单倍型频率的差异。结果-455G／A、-148C／T、448G／A多态性的基因型频率、等位基因频率在病例组和对照组之间的差异有统计学意义（P〈0．01），其余6个核苷酸多态性的基因型频率、等位基因频率在病例和对照组间的差异无统计学意义（P〉0．05），A^-455、T^-148、A^448携带者患缺血性脑卒中的相对危险度比非携带者分别大2．46倍、2．30倍和2．08倍。连锁不平衡分析未发现所分析的区域内存在单倍型板块。9个位点构建的单倍型在病例组和对照组之间的差异无统计学意义，以4个位点构建的单倍型中，某些单倍型在病例组和对照组之间的差异有统计学意义，对照组中某些携带G^-455、C^148、G^448位点的单倍型的频率高于病例组，而病例组中某些携带A^-455、T^-148、A^448位点的单倍型的频率高于对照组。结论多个位点和单倍型分析的结果提示8纤维白原455G／A、-148C／T、448G／A可能是海南汉族人群中与缺血性脑卒中关联的危险因素。     

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.     

HSPA5 promoter polymorphisms and risk of Parkinson's disease in Taiwan

Endoplasmic reticulum (ER) stress induced by misfolded proteins has been implicated in Parkinson's disease (PD) pathogenesis. A malfunction of unfolded protein response (UPR) to ER stress can result in PD as well as other neurodegenerative diseases. Heat shock 70 kDa protein 5 (HSPA5) is one of the UPR chaperones reactive to ER stress to block the apoptotic process. HSPA5 promoter polymorphisms -415 G/A (rs391957), -370 C/T (rs17840761) and -180 del/G (rs3216733) and their derived haplotypes may affect promoter activity of the gene. This study examines whether these HSPA5 promoter polymorphisms are associated with the risk of Taiwanese PD and the age of disease onset using a case-control study. Polymorphisms -415 G/A and -180 del/G were completely linked in our population (D'=1.00, Delta(2)=1.00). The genotype or allele frequency distribution of each HSPA5 polymorphism was not significantly different between the controls (n=341) and the PD patients (n=393). Neither the linked -415 G/A and -180 del/G nor -370 C/T polymorphism influences PD onset age. Our data suggest that the HSPA5 -415 G/A, -370 C/T, and -180 del/G polymorphisms are unlikely to play a major role in risk of developing PD in Taiwan.     

The complex interaction between APOE promoter and AD: an Italian case�Ccontrol study

The single nucleotide polymorphisms (SNPs) rs449647, rs769446 and rs405509 in the promoter region of the APOE gene have been variously suggested to be ɛ4-independent risk factors for Alzheimer''s disease (AD). A previous Italian study found that the rs449647 was significantly associated with late-onset AD. The aim of this study was to verify whether these APOE promoter SNPs are genetic risk factors for AD and to investigate their interaction with the common APOE polymorphism. A total of 169 clinically diagnosed AD patients and 99 cognitively intact age-matched controls were included in the study. Significant associations with AD independent from sex, age and APOE/ɛ4 status were found for rs449647 A/A and rs405509 G/G genotypes (positive), and rs449647 A/T and rs405509 T/T genotypes (negative). Haplotype frequency estimation at the APOE locus showed significant associations for the ATG4, ATT4 and ACG3 (positive) and ATT2, ATT3 and TCG3 (negative) haplotypes. Therefore this study confirms the role of the rs449647 A/A genotype as risk factor for AD in Italy and suggests that promoter genotypes and APOE haplotypes might have a complex function in AD-associated genetic risk factors.