Haplotype analysis of the human renin gene and essential hypertension

The human renin gene is an attractive candidate for involvement in the underlying cause of essential hypertension (EH). Despite extensive examination, the relation between the renin gene and hypertension remains unclear. The aims of the present study were to discover new genetic markers of EH and to investigate the relations between polymorphisms of the renin gene and EH in the Japanese. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we isolated 3 novel variants of the renin gene; a single nucleotide polymorphism (SNP) in intron 4 (T+17int4G), a variable number of tandem repeats (VNTR) polymorphism in intron 7, and a missense mutation in exon 9 (G1051A). We performed an association study with these polymorphisms in 212 patients with EH and 209 age-matched normotensive (NT) subjects. The frequency of genotypes VNTR and T+17int4G did not differ significantly between the 2 groups, whereas the overall distribution of G1051A was significantly different between EH and NT. Haplotype analysis revealed that the overall distribution of haplotypes differed significantly between the EH and NT groups. PRA levels in patients with EH with the G/G genotype were significantly higher than in subjects with EH with G/A and A/A genotypes. These data suggest that the missense mutation in exon 9 may affect the enzymatic function of renin and consequently may be involved in the etiology of hypertension.     

Systematic screening of type B human natriuretic peptide receptor gene polymorphisms and association with essential hypertension.

C-type natriuretic peptide (CNP) dilates arteries, lowers blood pressure and inhibits proliferation of vascular smooth muscle cells via the type B natriuretic peptide receptor (NPRB). The CNP-NPRB system may play a crucial role in the development of cardiovascular disease. We recently determined the structure of the human NPRB gene. In the present study, our objectives are to identify the polymorphisms of the NPRB gene and investigate the association of this gene with essential hypertension (EH). We used the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique to study the NPRB gene polymorphism, and conducted an association study using a novel polymorphic marker. PCR-SSCP analysis of all 22 exons was done in 90 subjects, and abnormally-migrating bands were observed in the analyses of exon 11 and intron 18. Direct sequencing of these DNA fragments revealed the following sequence alterations: a C to T transition at nucleotide (nt) 2077 in exon 11 and a 9-bp insertion/deletion (I/D) in intron 18. PCR-restriction fragment length polymorphism analysis (PCR-RFLP) was developed to detect the C2077T transition. PCR-RFLP analyses of healthy subjects revealed that the C2077T polymorphism had complete linkage to GT repeats in intron 2 reported previously. The I/D polymorphism was identified by polyacrylamide gel electrophoresis, and it was not linked to any known polymorphic alleles of this gene. Therefore, the possible association between the I/D polymorphism and EH was investigated. A total of 123 individuals with EH and 123 age-matched normotensive control subjects were studied. Overall distributions of allele frequencies in the two groups were not significantly different. Although the I/D polymorphism in intron 18 of the NPRB gene was not associated with EH, the results of this study, which identified two novel polymorphisms in the human NPRB gene, will facilitate further genetic analysis of this gene and cardiovascular disease.     

Association of the angiotensin-converting enzyme (ACE) gene G2350A dimorphism with essential hypertension

Although the angiotensin converting enzyme (ACE) is a strong candidate gene for hypertension, the extensively studied insertion-deletion dimorphism in intron 16 was not found to be associated with it. Several new polymorphisms in the ACE gene were identified, among which a dimorphism in exon 17, ACE G2350A, has a significant effect on plasma ACE concentrations. To assess the value of genotyping the ACE G2350A dimorphism in a genetically homogeneous population, we carried out a retrospective, case-control study of dimorphism G2350A for a putative association with essential hypertension (EH) in a Gulf population (Emirati)--an ethnic group characterized by no alcohol intake and no cigarette smoking. We investigated a sample population of 254 Emirati, comprising 136 normotensive controls, and 118 patients with clinical diagnoses of EH. ACE G2350A alleles were visualized by assays based on polymerase chain reaction and restriction endonuclease analysis. The ACE G2350A dimorphism showed an association with EH (chi2=6.71, 2 df, P=0.05). Further analysis revealed that the ACE G/G 2350 genotype was positively associated (OR=1.06-3.07, P=0.02) with EH. This is the first association study of the ACE G2350A dimorphism with EH, and the positive result might indicate that ACE could be a QTL for EH as originally thought.     

脑利钠肽基因型和生活习惯与高血压关系的病例对照研究

目的研究脑利钠肽（BNP）基因T-381C单核苷酸多态性和生活习惯与原发性高血压的关系。方法用病例-对照研究设计,选取高血压病例（高血压组）和与之年龄、性别匹配的按1：1配对的健康对照各796例（对照组）,运用PCR-限制片段多态（RFLP）技术检测BNP基因启动子区第381位点的T/C基因多态性,并比较不同基因型、生活习惯与高血压发病风险的关系。结果两组人群BNP基因T-381C等位基因的分布差异无显著性（χ~2=2.29,P=0.13）;高血压组CC基因型频率明显高于对照组,TC基因型频率低于对照组,三种基因型分布比较差异有统计学意义（χ~2=48.81,P〈0.05）。与携带TT或TC基因型者比较,携带CC基因型个体患高血压的风险增加（OR=1.98,95%CI 1.39～2.38）。吸烟显著增加了高血压风险（OR=2.30,95%CI1.70～2.91）,经常嗜酒（≥2次/周）增加高血压风险,OR处于临界值（OR=1.53,95%CI 1.19～1.89）,高盐饮食的作用较明显（OR=1.97,95%CI 1.48～2.31）,同时有吸烟、饮酒与高盐饮食习惯且携带CC基因型者发生高血压的风险增高,体育锻炼是保护性因素。结论原发性高血压与BNP基因T-381C多态性、生活习惯及它们之间的相互作用有关。     

肿瘤坏死因子β基因A80C多态与原发性高血压

目的:研究肿瘤坏死因子β(tumor necrosis factor-β,TNF-β)基因外显子1中的A80C多态与汉族人群原发性高血压的相关性。方法:采用基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)检测方法,在122例原发性高血压患者和202名健康对照者中,对TNF-β基因外显子1的A80C多态进行基因分型。结果:A80C多态的基因型分布及其等位基因频率在2组间相比均无显著性差异(P>0.05)。但在女性高血压患者中,其CC、CA和AA基因型分布与对照组相比有明显差异(P0.05)。女性CC基因型高血压患者的血清总胆固醇和低密度脂蛋白胆固醇浓度亦明显升高(P<0.01)。结论:TNF-β基因外显子1的A80C多态可能与女性原发性高血压的发生相关,尤其是携带CC基因型的女性。     

Allelic variants of natriuretic peptide receptor genes are associated with family history of hypertension and cardiovascular phenotype

OBJECTIVE: Abnormalities in the natriuretic peptide system could play a key role in the genesis of hypertension. We evaluated the associations between a family history of hypertension, cardiovascular phenotype and allelic variants of Npr1 and Npr3, two candidate genes that codify for natriuretic peptide receptors. METHODS: We genotyped 45 young normotensive subjects (19 males, 26.8 +/- 3.7 years) with accurately assessed family history of hypertension (FH+) and 52 (26 males, 26.1 +/- 3.1 years) without (FH-) for the known variants of Npr1 and Npr3 genes, and for a novel length difference (3C/4C) polymorphism at position 15129 in the 3'-untranslated region of the Npr1 gene. Blood pressure, echocardiography and plasma brain natriuretic peptide were assessed. RESULTS: Both the novel Npr1 3C allele (59 versus 33%, P < 0.001) and the 3C/3C genotype (31 versus 8%; P < 0.001) were significantly more frequent in FH+ than in FH-. The inverse distribution of the 4C/4C genotype suggested that a casual association was very unlikely. Moreover, the 3C/3C homozygous had significantly higher systolic blood pressure (121.1 +/- 6.3 versus 115.6 +/- 7.8 mmHg in 4C/4C; P < 0.05) and a longer left ventricular isovolumic relaxation time (67 +/- 10 versus 61 +/- 9 ms; P < 0.05). The Npr3 C(-55) allele variant was also more frequent in FH+ (88 versus 76%, P < 0.05), but was not associated with the cardiovascular phenotype. CONCLUSIONS: The novel Npr1 gene 3C variant and the Npr3 gene C(-55) allele are associated with hypertensive family history. Moreover, the functional Npr1 3C variant, when homozygous, is also associated with higher systolic blood pressure and prolonged ventricular relaxation.     

血管紧张素原M235T基因多态性对血压影响的研究

目的：研究血管紧张素原基因（ＡＧＴ）第二外显子Ｍ２３５Ｔ等位基因的多态性与高血压之间的关系。方法： 应用多聚酶链反应（ＰＣＲ）结合限制性酶切方法对１０５例健康体检者与１０２例原发性高血压（ＥＨ）患者进行基因突变的检测。结果：（１）ＥＨ患者Ｔ２３５ 等位基因频率（０．４４５）高于对照组（０．３２３）,Ｐ＜ ０．０５。在男性ＥＨ患者与男性对照组中差别更为明显（Ｐ＜ ０．０１）;（２）在有家族史的ＥＨ 患者中,Ｍ２３５Ｔ 突变基因型（ＴＴ型）频率高于正常对照组（４２．１％ ＶＳ１８．８％ ,Ｐ＜０．０５）。结论：（１）ＡＧＴ基因的突变与ＥＨ的发病具有相关性。对男性ＥＨ影响可能更大;（２）在有家族史的高血压患者中, ＡＧＴ２３５的ＴＴ基因型与ＥＨ有关     

A single-nucleotide polymorphism in the sterol-regulatory element-binding protein 1c gene is predictive of HIV-related hyperlipoproteinaemia

A single-nucleotide polymorphism (3'322C/G) was identified in the gene encoding a key cholesterol/triglyceride regulator, sterol-regulatory element-binding protein 1c (SREBP-1c). Although it did not alter the amino acid sequence, SREBP-1c-3'322C/G was predictive of highly active antiretroviral therapy-related hyperlipoproteinaemia. Increases in cholesterol were less frequently associated with homozygous SREBP-1c-3'322G (genotype 22) than with heterozygous/homozygous SREBP-1c-3'322C (genotypes 11/12) and correlated with leptin and insulin increases, particularly in genotype 11/12 carriers. A functional mutation linked to SREBP-1c-3'322C/G or messenger RNA conformation differences may explain our findings.     

E-选择素第2外显子G98T基因多态性与高血压病的相关性研究

目的 观察原发性高血压病(EH)患者E-选择素(E-selectin)基因第2外显子G98T多态性,并探讨高血压发病的遗传学机制。方法 应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术检测155例高血压患者和160例正常对照者E-selectin基因型,生化技术测定血脂水平。结果 E-selectin基因型GG、GT频率在高血压组和对照组分别为85.2％、14.8％和92.5％、7.5％;等位基因G、T频率在高血压组和对照组分别为92.6％、7.4％和96.3％、3.7％。基因型频率和等位基因频率在高血压组和对照组比较差异均有显著性(P<0.05)。结论 E-selectin第2外显子G98T基因多态性与高血压的发病有关性,T等位基因可能是高血压发病的危险因素之一。     

Association study between the variants of the human ANP gene and essential hypertension.

Variants of atrial natriuretic peptide (ANP) are reported to be more common in blacks with hypertension than in normotensive controls and constitute an independent risk factor for cerebral infarction. The purpose of the present study was to investigate the role of ANP in the pathogenesis of essential hypertension (EH) in the Japanese. We investigated 2 previously reported ANP gene markers, G1837A and T2238C, for their possible associations with EH. A total of 233 individuals with EH and 213 age-matched normotensive (NT) control subjects were studied. The frequencies of the G and A alleles were 0.09 (42/466) and 0.91 (424/466), respectively, for the NT group and 0.11 (47/426) and 0.89 (379/426), respectively, for the EH group. These frequencies did not differ significantly between the two groups. The frequencies of the T and C alleles were 0.024 (11/466) and 0.97 (455/466), respectively, for the NT group and 0.03 (13/426) and 0.97 (413/426), respectively, for the EH group. These frequencies also did not differ significantly between the two groups. Neither G1837A nor the T2238C polymorphism of the ANP gene was associated with EH. Our findings do not support the hypothesis that the G1837A and T2238C polymorphisms of the ANP gene are markers for EH in the Japanese.     

The methylentetrahydrofolate reductase gene variant (C677T) as a risk factor for essential hypertension in Caucasians.

Essential hypertension (EH) is a common, multifactorial disorder likely to be influenced by multiple genes of modest effect. The methylenetetrahydrofolate reductase (MTHFR) gene C677T mutation is functionally important, being strongly associated with reduced enzyme activity and increased plasma levels of homocysteine. Mild hyperhomocysteinemia is a known risk factor for cardiovascular disease (CVD) and hypothesised also to be involved in hypertension pathophysiology. The present study was performed to determine the prevalence of the 677T mutation in Australian Caucasian patients diagnosed with EH and to test whether the C677T variant is associated with the disorder. A case-control cohort, consisting of 250 EH patients and 250 age, sex and racially matched normotensive controls, were used for the association study. Comparison of C677T allele frequencies revealed a higher proportion of the mutant allele (T) in the EH group (40%) compared to unaffected controls (34%) (p=0.07). Furthermore, genotypic results indicated that the prevalence of the homozygous mutant genotype (T/T) in the affected group was higher than that of controls (14%:10%) (p=0.17). Interestingly, conditional logistic regression showed that the MTHFR C677T mutation conferred a mild, yet significant increase in risk of essential hypertension after adjusting for body mass index (odds ratio=1.57, 95% confidence interval: 1.04-2.37, p=0.03). These findings require further investigation in large independent samples, but suggest that essential hypertension, like CVD, may be mildly influenced by the MTHFR C677T variant.     

A single-nucleotide polymorphism in C-type natriuretic peptide gene may be associated with hypertension.

We conducted an association study between genetic variants of C-type natriuretic peptide gene (CNP) and hypertension in a Japanese population. We found four genetic variants, two in the promoter region, one missense mutation, and one in the 3'-untranslated region (3'-UTR), and genotyped all four variants in 2,006 subjects recruited from the Suita study. One of the variants, G2628A in 3'-UTR, was found to be associated with blood pressure. Multiple logistic analyses indicated that the genotype of the G2628A polymorphism (GG=1, GA+AA=2) (p=0.0034), sex (p=0.0288), alcohol consumption (p=0.0002), age (p<0.0001), and body mass index (p<0.0001) were predictors of hypertension. The odds ratio of the GA+AA genotype over the GG genotype for hypertension was 1.40 (p=0.0034, 95% confidence interval (CI) 1.12-1.75). Multiple logistic analyses in a younger subpopulation aged below 65 years indicated that the odds ratio of the GA+AA genotype over the GG genotype for hypertension was 1.58 (p=0.0024, 95%CI 1.18-2.12). Thus, the CNP G2628A polymorphism made an even greater contribution to hypertension in the younger subpopulation.     

新疆哈萨克族β2肾上腺素能受体基因C659G变异与原发性高血压相关

目的 研究人类β2肾上腺素能受体(ADRB2)基因C659G变异与新疆哈萨克族原发性高血压(EH)的关系.方法 采用聚合酶链反应法及限制性内切酶片段长度多态性技术(PCRRFLP),对新疆哈萨克族273例EH患者(EH组)及162例正常血压者(NT组)进行ADRB2基因C659G多态性检测,观察CC、cG和GG不同基因型以及该位点C、G不同等位基因频率在EH组和NT组中的分布.结果 435例哈萨克族人ADRB2基因C659G基因型频率分别为CC 85.75%、CG13.79%、GG 0.46%,等位基因频率分别为C 7.36%、G 92.64%.EH组与NT组基因型及等位基因频率的分布差异有统计学意义(P＜0.05).G等位基因为EH危险因子,OR值为12.37.各基因型问年龄、体质指数、收缩压以及舒张压差异有统计学意义(P＜0.05),同时在校正年龄、体质指数后,各基因型间收缩压及舒张压水平存在明显差异并有统计学意义(P＜0.05).结论 新疆哈萨克族人ADRB2基因C659G多态性与EH存在相关关系,提示该多态性可能在哈萨克族人EH的发病机制中起作用.     

脑利钠肽T-381C基因多态性与高血压的关系

目的探讨脑利钠肽T-381C基因多态性与高血压的关系。方法高血压患者(高血压组)138例,健康人(对照组)141例。两组年龄、体质量指数无差异。对两组进行血压测量,空腹采血检测血糖、总胆固醇、三酰甘油、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇等。聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法进行DNA多态性分析,琼脂糖凝胶电泳判断基因型。结果检测到TY、TC、CC 3种基因型。在高血压与对照组之间基因型构成比差异有统计学意义(P<0.05)。在高血压组TC-CC基因型和C等位基因频率(30.43%和17.75%)显著高于对照组(分别为19.86%和10.64%),P=0.042和0.016。TT基因型比TC-CC基因型的空腹血糖更高,差异有统计学意义(P<0.05)。结论脑利钠肽T-381C基因多态性可能对高血压有影响,TC-CC基因型和C等位基因发生高血压的风险较大。     

原发性高血压患者血清CD40水平及脉搏波速率与CD40基因多态性的关系

目的：探讨原发性高血压患者CD40基因多态性与血清CD40水平及脉搏波速率的联系。方法：研究对象为432名原发性高血压患者。以酶联免疫反应法测定血清可溶性CD40（sCD40）水平。用Taqman聚合酶链式反应（PCR）方法测定CD40基因三种类型（A/G、C/T、T/C）,分析CD40基因多态性与血清CD40浓度、脉搏波速率（PWV）的联系。结果：有CD40基因A/G中的GA[GA：（43.4±4.2）pg/ml比AA：（29.6±1.6）pg/ml,GG：（39.8±6.5）pg/ml]、C/T中的CT[CT：（42.1±4.2）pg/ml比CC：（37.1±7.6）pg/ml,TT：（30.6±1.5）pg/ml]、T/C中的TT[TT：（43.3±5.3）pg/ml比TC：（32.3±1.3）pg/ml,CC：（30.7±3.7）pg/ml]等三种基因型的高血压患者的sCD40水平均较其他相应基因型显著升高（P〈0.05～0.01）;有A/G中的GG[GG：（9.5±0.3）m/s比AA：（9.0±0.1）m/s,GA：（8.8±0.1）m/s]、C/T中的CC[CC：（9.6±0.3）m/s比CT：（8.9±0.1）m/s,TT：（9.0±0.5）m/s]、T/C中的CC[CC：（9.3±0.2）m/s比TT：（9.0±0.1）m/s,TC：（8.9±0.1）m/s]等三种基因型的高血压患者的PWV均较其他相应基因型明显增快（P均〈0.05）。结论：CD40的三种基因多态性与血清CD40浓度、脉搏波速率有关。     

Mutation analysis of the transferrin receptor-2 gene in patients with iron overload

Three mutations in the transferrin receptor-2 gene have recently been identified in four Sicilian families with iron overload who had a normal hemochromatosis gene, HFE (C. Camaschella, personal communication). To determine the extent to which mutations in the transferrin receptor-2 gene occur in other populations with iron overload, we have completely sequenced this gene in 17 whites, 10 Asians, and 8 African Americans with iron overload and a C282C/C282C HFE genotype, as well as 4 subjects without iron overload and homozygous for the mutant HFE C282Y genotype, 5 patients with iron overload and homozygous for the mutant HFE C282Y genotype, and 5 normal individuals. None of the individuals exhibited the Sicilian mutations, Y250X in exon 6, M172K in exon 4, and E60X in exon 2. One iron-overloaded individual of Asian descent exhibited a I238M mutation which was subsequently found to be a polymorphism present in the Asian population at a frequency of 0.0192. The presence of the I238M mutation was not associated with an increase in ferritin or transferrin saturation levels. Three silent polymorphisms were also identified, nt 1770 (D590D) and nt 1851 (A617A) and a polymorphism at nt 2255 in the 3' UTR. Thus, mutations in the transferrin receptor-2 gene were not responsible for the iron overload seen in our subjects.     

同型半胱氨酸相关酶基因多态性与高血压伴周围动脉闭塞性疾病的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T、胱硫醚B合成酶(CBS)基因844ins68和甲硫氨基合成酶(MS)基因A2756G3种同型半胱氨酸(Hcy)代谢相关酶基因多态性与北京社区汉族老年人群中原发性高血压(EH)、EH伴周围动脉闭塞性疾病(PAOD)易感性的关系。方法PCR扩增老年EH(EH组)、老年EH伴PAOD(EH—PAOD组)患者和老年健康对照组的MTHFR C677T、CBS 844ins68、MS A2756G基因突变点，直接或经限制性内切酶消化后行凝胶电泳，确定基因型并统计基因突变频率。结果EH组100例MTHFR基因3种基因型频率为：C／C29．0％，C／T45．0％，T／T26．0％；EH—PAOD组59例为：C／C15．9％，C／T35．5％，T／T48．6％；对照组100例为：C／C31．0％，C／T50．0％，T／T19．0％。3组MTHFR基因的C677T单核苷酸突变中T突变位点的频率分别为48．5％、64．4％、44．0％。EH—PAOD组与对照组和EH组比较，MTHFR T／T基因型频率和T等位基因频率差异均有统计学意义。而CBS 844ins68、MS A2756G各种基因型频率和等位基因频率在EH组、EH—PAOD组和对照组之间差异无统计学意义。结论MTHFR基因C677T单核苷酸突变可能是北京社区汉族老年人PAOD的遗传性危险因素之一，可能与EH无关。且CBS基因844ins68、MS基因A2756G的突变可能都不足以成为EH和PAOD的遗传危险因子。