Genetic association analyses of non-synonymous single nucleotide polymorphisms in diabetic nephropathy

Aims/hypothesis  Diabetic nephropathy, characterised by persistent proteinuria, hypertension and progressive kidney failure, affects a subset of susceptible individuals with diabetes. It is also a leading cause of end-stage renal disease (ESRD). Non-synonymous (ns) single nucleotide polymorphisms (SNPs) have been reported to contribute to genetic susceptibility in both monogenic disorders and common complex diseases. The objective of this study was to investigate whether nsSNPs are involved in susceptibility to diabetic nephropathy using a case-control design. Methods  White type 1 diabetic patients with (cases) and without (controls) nephropathy from eight centres in the UK and Ireland were genotyped for a selected subset of nsSNPs using Illumina’s GoldenGate BeadArray assay. A χ ² test for trend, stratified by centre, was used to assess differences in genotype distribution between cases and controls. Genomic control was used to adjust for possible inflation of test statistics, and the False Discovery Rate method was used to account for multiple testing. Results  We assessed 1,111 nsSNPs for association with diabetic nephropathy in 1,711 individuals with type 1 diabetes (894 cases, 817 controls). A number of SNPs demonstrated a significant difference in genotype distribution between groups before but not after correction for multiple testing. Furthermore, neither subgroup analysis (diabetic nephropathy with ESRD or diabetic nephropathy without ESRD) nor stratification by duration of diabetes revealed any significant differences between groups. Conclusions/interpretation  The nsSNPs investigated in this study do not appear to contribute significantly to the development of diabetic nephropathy in patients with type 1 diabetes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

诱导型一氧化氮合酶基因多态性与糖尿病肾病的关系

采用基因测序方法研究诱导型一氧化氮合酶(iNOS)基因多态性的分布及与糖尿病肾病(DN)的关系,发现其多态性在不同种族的分布差异有统计学意义,但iNOS基因多态性与DN无显著相关。     

Genetic association studies in diabetic nephropathy

Clinical observations and epidemiological studies have shown that there is familial aggregation of diabetic nephropathy in many ethnic groups, indicating the strong contribution of inherited factors in the development of diabetic nephropathy. Identification of the genes involved in the pathogenesis of diabetic nephropathy may provide better knowledge of its pathophysiology and future therapies. To search for the genes involved in susceptibility, resistance or progression to diabetic nephropathy, candidate gene population association, family-based association and genome wide association studies have been widely used. This article reviews genetic polymorphisms, summarizes the data from genetic association studies of diabetic nephropathy in both type 1 and type 2 diabetes, and discusses about the future genetic analyses in the complex diseases.     

Patterns of hyperinsulinaemia in type 1 diabetic patients with and without nephropathy

The prevalence and patterns of insulinaemia in five groups of patients with Type 1 diabetes have been reinvestigated using a free insulin assay which minimizes in vitro redistribution of the free and antibody-bound insulin components. In 18 diabetic patients managed by conventional insulin injection treatment and 19 patients treated by continuous subcutaneous insulin infusion (CSII), the mean 24-h serum free insulin level exceeded a non-diabetic reference range in 78% (injections) and 68% (CSII). Twenty-four-hour profiles showed that hyperinsulinaemia occurred in the basal state before meals and at night, but not immediately post-prandially. The serum free insulin concentration at 0800 h, 1200 h, and 1600 h was significantly (p less than 0.001) correlated with mean 24-h free insulin in injection-treated and CSII patients, and samples at one of these time-points may thus provide a simple, single measure of integrated insulinaemia for population studies. There was no significant difference in 24-h mean free insulin levels in 7 patients randomly crossed-over between injection treatment and CSII, but the profiles had a more physiological pattern during CSII, with a mean post-prandial serum free insulin level which was significantly higher on CSII than injections (mean +/- SE = 37.2 +/- 3.1 vs 26.9 +/- 2.5 mU l-1, p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

2型糖尿病肾病患者血清脂联素的水平

糖尿病肾病（DN）组血清脂联素水平较单纯糖尿病组显著升高；大量白蛋白尿组血清脂联素水平较正常对照组、单纯糖尿病组、早期DN组显著升高。脂联素水平与24h尿白蛋白排泄率呈正相关，与腰臀比呈负相关。DN大量白蛋白尿期血清脂联素水平显著升高，其机制尚不清楚。     

Maternal history of type 2 diabetes is associated with diabetic nephropathy in type 1 diabetic patients

AIMS: Insulin resistance is a key feature of type 2 diabetes. It is also involved in the development and progression of microvascular complications. We analysed the relationship between parental history of diabetes, insulin resistance and diabetic nephropathy (DN) and assessed the specific maternal and paternal influences of history of type 2 diabetes on DN in type 1 diabetic offspring. METHODS: We recorded information regarding family history of type 2 diabetes and of cardiovascular disease in 160 consecutive, unrelated type 1 diabetic patients. Insulin resistance was assessed using a validated estimation of the glucose disposal rate (eGDR). RESULTS: Type 1 diabetic patients with a maternal history of type 2 diabetes were more likely to be insulin-resistant (P=0.043) and to have renal complications (P=0.0041) than those from the reference group (without parental history of diabetes), while patients with a paternal history were not different from those from the reference group, regarding eGDR and DN. Time to development of abnormal albuminuria was significantly affected by maternal history of type 2 diabetes (log-rank=12.66; P=0.0004) and by familial history of premature cardiovascular disease (log-rank=5.48; P=0.0234). In multivariate analysis, a maternal history of type 2 diabetes was independently associated with nephropathy after adjustment for sex, diabetes duration and familial history of premature cardiovascular disease. CONCLUSION: Maternal history of type 2 diabetes is independently associated with DN in type 1 diabetic patients. This might suggest the transmission of a maternal trait related to microvascular complications, raising the hypothesis of imprinted genes predisposing to diabetic renal disease.     

2型糖尿病肾病患者血清脂联素水平的变化

目的:观察2型糖尿病肾病(DN)患者血清脂联素(adiponectin, ADPN)水平变化及其临床意义. 方法:正常对照组(NC)10例;2型糖尿病患者53例,根据尿白蛋白排泄率(UAER)及血清肌酐(SCr)水平分成糖尿病组(DM,UAER<30 mg/g,SCr<132.6 μmol/L)、糖尿病肾病组(DN1,≥30 mg/g,SCr<132.6 μmol/L)和晚期糖尿病肾病组(DN2,UAER≥300 mg/g,SCr>132.6 μmol/L);应用酶联免疫吸附法(ELISA)测定各组血清中的ADPN、可溶性血管细胞粘附分子1(sVCAM-1)水平. 结果:DN2组的血清ADPN水平高于NC组、DM组和DN1组(P<0.05);DN1组的ADPN高于NC组和DM组,但无统计学差异;DM组的ADPN水平低于NC组,但无统计学差异.sVCAM-1在NC组、DM组、DN1组和DN2组依次逐渐增高.相关分析显示ADPN与尿酸(UA)、SCr、肾小球滤过率(eGFR)呈显著相关关系(P<0.05),多元逐步回归分析显示SCr是ADPN的独立相关因素(决定系数为r2＝0.265,β＝3.130,P<0.01).无论在研究对象总体还是糖尿病患者中,ADPN与sVCAM-1均呈正相关性(相关系数分别为0.331,P<0.01;0.316,P<0.05) 结论:2型糖尿病肾病患者血清ADPN水平升高可能与肾功能减退有关,血清ADPN升高可能参与了糖尿病肾病患者的内皮功能损害机制.     

中国汉族人群载脂蛋白E基因多态性与2型糖尿病肾病相关性的Meta分析

目的 评价中国汉族人群载脂蛋白E(ApoE)基因多态性与2型糖尿病肾病(T2DN)的相关性.方法 全面检索T2DN与ApoE基因多态性的相关文献,用Meta分析方法对研究结果进行数据合并,并评价分析结果稳定性和可靠性.结果 T2DN组较之T2DNN组ApoE基因E2、E2/E2和E2/E3的合并OR值及其95% CI分别为2.08 (1.55～2.77)、2.75 (1.09～7.01)和2.10 (1.48～2.96)(P＜0.05),T2DN组较之NC组分别为2.62 (2.01～3.41)、3.63 (1.61～8.16)和2.64 (1.67～4.16)(P＜0.05).T2DN组较之T2DNN组E3和E3/E3的合并OR值及其95% CI分别为0.67 (0.54～0.82)和0.62 (0.48～0.79)(P＜0.05),T2DN组较之NC组为0.53 (0.41～0.70)和0.49 (0.39～0.62)(P＜0.05).结论 中国汉族人群T2DN与ApoE基因多态性关系密切,等位基因 E2是T2DN的危险因子,等位基因E3可能是T2DN的保护因子.     

Genetic association study of adiponectin polymorphisms with risk of Type 2 diabetes mellitus in Korean population.

AIMS: To investigate any association between Type 2 diabetes mellitus and two single nucleotide polymorphisms (SNPs) in the adiponectin gene, T45G and G276T, in the Korean population. METHODS: We genotyped 427 non-diabetic controls and 493 Type 2 diabetic patients for SNPs T45G and G276T of adiponectin gene, measured plasma adiponectin concentrations, and examined clinical parameters in Koreans. RESULTS: There were no statistically significant differences in allele frequencies of SNPs 45 and 276 comparing control with Type 2 diabetic subjects (T frequency 68.3% vs. 71.6%, P=0.13 for SNP45, G frequency 72.2% vs. 68.9%, P=0.12 for SNP276). The genotype distributions of these SNPs had no association with the risk of Type 2 diabetes and metabolic parameters of insulin resistance. Plasma levels of adiponectin were not statistically different according to T45G and G276T either, in both control and Type 2 diabetic subjects. CONCLUSION: The T45G and G276T of the adiponectin gene may not be an important determinant of Type 2 diabetes or insulin resistance in Korean subjects.     

Telomere length and progression of diabetic nephropathy in patients with type 1 diabetes

Abstract. Fyhrquist F, Tiitu A, Saijonmaa O, Forsblom C, Groop P‐H, on behalf of the FinnDiane Study Group (Minerva Institute for Medical Research; Helsinki University Central Hospital; and Folkhälsan Institute of Genetics; Helsinki, Finland). Telomere length and progression of diabetic nephropathy in patients with type 1 diabetes. J Intern Med 2010; 267 : 278–286. Objectives. To determine whether short telomere length of blood leucocytes from patients with type 1 diabetes is associated with or predictive of progression of diabetic nephropathy. Design and methods. Two consecutive DNA samples were obtained from 132 patients from the nationwide Finnish Diabetic Nephropathy Study with type 1 diabetes. Control DNA samples were taken from 44 healthy blood donors. Telomere length was measured by Southern blot. Patients were divided into three groups according to their urinary albumin excretion rate (AER): 48 patients with normoalbuminuria (AER < 20 μg min^?1); seven patients with microalbuminuria (AER ≥ 20 μg min^?1 <200 μg min^?1) and 77 patients with macroalbuminuria (AER ≥ 200 μg min^?1). Progression was defined as a change in albuminuria to a higher level. Results. Progression occurred in 21 patients. Progressors had shorter mean telomere length (8.1 ± 0.7 kb, mean ± SD; P = 0.017) and higher percentage of short telomeres (32.0 ± 8%, P = 0.002) than nonprogressors (8.5 ± 0.7 kb and 27 ± 7.2%, respectively). Thus, both shorter telomeres (HR = 0.190, 95%CI 0.065–0.558, P = 0.0025) and higher proportion of short telomeres (HR = 1.115, 1.039–1.195, P =0.0023) were independent predictors of diabetic nephropathy. Telomere length was not associated with the degree of albuminuria and was not different in patients with type 1 diabetes compared with healthy controls. Conclusions. Short telomeres are independent predictors of progression of diabetic nephropathy in patients with type 1 diabetes.     

Lack of association of angiotensin II type 1 receptor gene polymorphism with diabetic nephropathy in insulin-dependent diabetes mellitus

Several observations suggest that inherited factors are influential in the development of nephropathy in patients with insulin-dependent diabetes mellitus (IDDM). Genetic components of the renin angiotensin system are possible candidate genes. The aim of this study was to determine the role of the hypertension associated angiotensin II type 1 receptor (AT1R) gene A¹¹⁶⁶C polymorphism in susceptibility to nephropathy in IDDM. We examined 264 Caucasoid patients with IDDM and overt nephropathy (as defined by persistent proteinuria in the absence of other causes, hypertension and retinopathy), 136 IDDM patients with long duration of diabetes and no nephropathy (LDNN group), 200 recently diagnosed IDDM patients (Sporadic Diabetic group), and 212 non-diabetic subjects. The AT1R gene polymorphism was assessed using the polymerase chain reaction and restriction isotyping. Genotype frequencies did not differ significantly between the sporadic diabetic group and the nephropathy group (p = 0.245), nor between the long duration non-nephropathy group and the nephropathy group (p = 0.250). Allele frequencies were not significantly different between the three groups (p = 0.753). We conclude that there is no significant association between the hypertension associated AT1R gene polymorphism and diabetic nephropathy in patients with IDDM in the UK. © 1997 John Wiley & Sons, Ltd.     

Absence of an association between the polymorphisms in the genes encoding adiponectin receptors and type 2 diabetes

Aims/hypothesis Secreted by adipocytes, adiponectin is a hormone that acts as an antidiabetic and anti-atherogenic adipokine. We recently cloned the genes encoding two adiponectin receptors (ADIPOR1 and ADIPOR2). The aim of this study was to examine whether ADIPOR1 and/or ADIPOR2 play a major role in genetic susceptibility to insulin resistance or type 2 diabetes in the Japanese population.Methods By direct sequencing and a search of public databases, we identified single nucleotide polymorphisms (SNPs) in ADIPOR1 and ADIPOR2, and investigated whether these SNPs are associated with insulin resistance and type 2 diabetes in the Japanese population.Results The linkage disequilibrium (LD) in the chromosomal region of ADIPOR1 was almost completely preserved, whereas the LD in ADIPOR2 was less well preserved. None of the SNPs in ADIPOR1 or ADIPOR2 were significantly associated with insulin resistance or type 2 diabetes. No differences in ADIPOR1 or ADIPOR2 haplotype frequencies were observed between type 2 diabetic and non-diabetic subjects.Conclusions/interpretation Genetic variations in ADIPOR1 or ADIPOR2 are unlikely to lead to a common genetic predisposition to insulin resistance or type 2 diabetes in the Japanese population.Electronic supplementary material Supplementary material is available for this article at .     

ACE基因、AT1R基因多态性与2型糖尿病肾病的关系

目的研究血管紧张素I转化酶(ACE)基因/D多态及血管紧张素受体1型(AT1R)A1166C多态性与中国汉族人2型糖尿病肾病(DN)的关系。方法运用聚合酶链反应(PCR)和PCR/DdeI酶切技术,检测93例DN患者(DN组)与94例2型糖尿病患者(DM组)ACE基因及AT1R基因多态基因型。结果DN组ACE基因DD基因型频率(34.4%)、D型等位基因频率(54.3%)较DM组(19.1%,40.4%)均升高(P<0.05,<0.01);两组间AT1R基因A1166C多态基因型频率和等位基因频率分布均无差异(P>0.05);ACE和AT1R基因多态与DN的分层分析显示,同时携带ACE纯合子缺失基因型(DD)和AT1R突变基因型(AC+CC)者发生DN的危险较大,OR值为8.569。结论ACE基因/D多态性与2型DM并发DN有关,携带DD基因型和D型等位基因的2型DM患者是DN的易感人群。ATlR基因A1166C多态性虽与我国汉族人2型DM并发DN无关,但AT1R与ACE基因多态存在协同效应,携带AC+CC与DD基因型的个体有更高的患DN风险。     

White coat hypertension in type 1 diabetic patients without nephropathy

The aim of our study was to determine the prevalence of white coat hypertension (WCH) in type 1 diabetic patients. Therefore, ambulatory blood pressure monitoring (ABPM) and 24-h urinary albumin excretion (UAE) were determined in 47 patients with type 1 diabetes mellitus (27 with new diagnosis of hypertension by office blood pressure (BP) measurement and 20 with normotension). WCH was diagnosed in 20 patients (74%). Patients with WCH presented higher values of systolic and diastolic BP and UAE than normotensive patients. The results indicate that in type 1 diabetes mellitus WCH is very frequent. Thus, WCH may represent a potential risk for the development of diabetic complications, mainly diabetic nephropathy.     

Genetic association analysis of LARS2 with type 2 diabetes

Aims/hypothesis

LARS2 has been previously identified as a potential type 2 diabetes susceptibility gene through the low-frequency H324Q (rs71645922) variant (minor allele frequency [MAF] 3.0%). However, this association did not achieve genome-wide levels of significance. The aim of this study was to establish the true contribution of this variant and common variants in LARS2 (MAF?>?5%) to type 2 diabetes risk.

Methods

We combined genome-wide association data (n?=?10,128) from the DIAGRAM consortium with independent data derived from a tagging single nucleotide polymorphism (SNP) approach in Dutch individuals (n?=?999) and took forward two SNPs of interest to replication in up to 11,163 Dutch participants (rs17637703 and rs952621). In addition, because inspection of genome-wide association study data identified a cluster of low-frequency variants with evidence of type 2 diabetes association, we attempted replication of rs9825041 (a proxy for this group) and the previously identified H324Q variant in up to 35,715 participants of European descent.

Results

No association between the common SNPs in LARS2 and type 2 diabetes was found. Our replication studies for the two low-frequency variants, rs9825041 and H324Q, failed to confirm an association with type 2 diabetes in Dutch, Scandinavian and UK samples (OR 1.03 [95% CI 0.95–1.12], p?=?0.45, n?=?31,962 and OR 0.99 [0.90–1.08], p?=?0.78, n?=?35,715 respectively).

Conclusions/interpretation

In this study, the largest study examining the role of sequence variants in LARS2 in type 2 diabetes susceptibility, we found no evidence to support previous data indicating a role in type 2 diabetes susceptibility.     

中国人醛糖还原酶基因5'端(AC)n多态性与2型糖尿病肾病相关性的meta分析

目的 对中国人醛糖还原酶基因5'端(AC)n多态性与2型糖尿病合并糖尿病肾病相关性的研究进行meta分析.方法 通过文献检索收集2007年4月以前发表的中国人醛糖还原酶基因5'端(AC)n多态性与2型糖尿病合并糖尿病肾病相关性的病例-对照研究,剔除不符合要求的文献,以漏斗图检验入选文献的发表偏倚,并根据各入选文献的同质性检验结果进行数据合并,计算总OR值,meta分析采用Review Manager 4.2版统计软件.结果 共8篇文献符合条件纳入研究,入选文献无明显发表偏倚,各文献同质性检验显示有关Z-2(χ2=18.20,P=0.01)、Z+2(χ2=35.30,P<0.01)等位基因分布情况的文献间均存在显著异质性.Z～2等位基因增加2型糖尿病肾病的易感性(OR=1.72,95%CI 1.25-2.36,P<0.01),Z+6等位基因对2型糖尿病患者肾脏具有保护作用(OR=0.66,95%17/0.45-0.98,P=0.04),Z+2等位基因对糖尿病肾病的易感性无影响(OR=0.73,95%CI 0.47-1.12,P=0.15).结论 醛糖还原酶基因5'端(AC)n多态性与中国人2型糖尿病合并糖尿病肾病易感性相关,Z-2等位基因可能是2型糖尿病患者糖尿病肾病的易感基因,Z+6等位基因可能对2型糖尿病患者肾脏具有保护作用.