The insulin polymorphism -23Hph increases the risk for type 1 diabetes mellitus in the Romanian population

The insulin -23Hph and IGF2 Apa polymorphisms were genotyped in Romanian patients with T1DM (n = 204), T2DM (n = 215) or obesity (n = 200) and normoponderal healthy subjects (n = 750). The genotypes of both polymorphisms were distributed in concordance with Hardy-Weinberg equilibrium in all groups. The -23Hph AA genotype increased the risk for T1DM (OR: 3.22, 95%CI: 2.09-4.98, p < 0,0001), especially in patients without macroalbuminuria (OR: 4.32, 95%CI: 2.54-7.45, p < 0,0001). No other significant association between the alleles or genotypes of insulin -23Hph and IGF2 Apa and diabetes or obesity was identified

New susceptibility loci associated with kidney disease in type 1 diabetes

WOS:000309817900008Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genome-wide association studies (GWAS) of T1D DN comprising ∼2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P = 1.2×10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P = 2.0×10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-β1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P = 2.1×10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.Peer reviewe

Autoimmune diseases and vitamin D receptor Apa-I polymorphism are associated with vitiligo in a small inbred Romanian community

Vitiligo has been associated with the host's genetic profile, metabolic abnormality and immunostatus. The purpose of this study was to investigate the association of vitiligo with autoimmune diseases for 31 out of 39 subjects with vitiligo and their first-degree relatives living in a small Caucasian inbred rural community. They were compared with healthy individuals. A 2.28% prevalence of vitiligo was calculated and the presence of consanguine marriages (72.3%) was noted for this community. Our results indicate an increased prevalence of thyroidopathies, diabetes mellitus and rheumatoid arthritis in families with vitiligo. We also show that the Apa-I polymorphism of the vitamin D receptor gene is associated with vitiligo. This is the first study of its kind performed in Romania suggesting that the vitamin D receptor gene might play a role in the aetiopathogenesis of skin depigmentatio

Forest plots for significant hits incorporating discovery and replication plots.

<p>Plots show the study-specific association estimates (OR) and 95% confidence intervals for the discovery and second phase studies. (A) Association of rs7583877 with ESRD; heterogeneity <i>P</i> = 0.037. (B) Association of rs12437854 with ESRD; heterogeneity <i>P</i> = 0.046. (C) Association of rs7588550 with DN; heterogeneity <i>P</i> = 0.467. The association estimate and confidence interval for the meta-analysis combining the discovery and second-stage results are denoted by the diamond.</p

AFF3 is upregulated in renal epithelial cells (HK-2) stimulated with pro-fibrotic TGF-β1.

<p>(A) Western blot of AFF3 protein expression in HK-2 cells stimulated with TGF-β1 (5 ng/ml; 24–48 h). (B) TaqMan quantitative PCR analysis of AFF3 mRNA expression in HK-2 cells stimulated with TGF-β1 (5 ng/ml; 48 h) and (C) AFF3 mRNA expression in HK-2 cells transfected with AFF3 siRNA in the presence (black bar)/absence (grey bar) of TGF-β1 (5 ng/ml; 48 h). (D) TaqMan quantitative PCR analysis of N-cadherin, CTGF, Jagged1 and E-cadherin expression in HK-2 cells transfected with AFF3 siRNA in the presence (black bar)/absence (grey bar) of TGF-β1 (5 ng/ml; 48 h). (E) Representative Western blot of N-cadherin, CTGF, Jagged1 and E-cadherin protein responses in HK-2 cells transfected with AFF3 siRNA in the presence/absence of TGF-β1 (5 ng/ml; 48 h). HK-2 cells transfected with control siRNA were selected as a control. For TaqMan PCR, expression was normalized to GAPDH. Data are plotted as mean ± SE (n = 3; *<i>P</i><0.05, **<i>P</i><0.01).</p

Regional association plots for top ranked SNPs with associated gene expression data.

<p>Panels represent independent signals for the primary DN and ESRD analysis. The color of the SNP symbol indicates the linkage disequilibrium (r²) with the index SNP which is colored purple. Blue and red gene colors in the lower part of each figure panel indicate up and down regulation in tubulointerstitial or glomerular DN kidney biopsies, respectively. Genes with no change in expression are indicated with black; no data on gene expression with gray color. (A) Association of rs7583877 with ESRD. (B) Association of rs12437854 with ESRD. (C) Association of rs7588550 with DN.</p

Results from discovery, second stage, and combined meta-analysis for supported markers.

<p>A1 = minor allele = effect allele; A2 = major allele; Freq(A1) = minor allele frequency; OR = odds ratio; 95% CI = 95% confidence interval. Discovery: Meta analysis results for GENIE discovery cohorts. Stage 2: Meta analysis results for replication cohorts. Combined: Meta analysis results for discovery and the stage 2 cohorts. NA = no result, due to genotype failure or quality control filtering.</p

Characteristics of samples successfully analyzed in each discovery collection and the meta-analyses.

<p>n = total number of patients; Micro = patients with microalbuminuria; M/F = number of males/females; HbA_1C blood glycosylated hemoglobin; BMI = body mass index. Case = macroalbuminuria or ESRD, Control = normoalbuminuric, see text for full details.</p