To search for a gene(s) conferring susceptibility to diabetic nephropathy (DN), we genotyped over 80,000 genebased single nucleotide polymorphisms (SNPs) in Japanese patients and identified that the engulfment and cell motility 1 gene (ELMO1) was a likely candidate for conferring susceptibility to DN, in view of the significant association of an SNP in this gene with the disease (intron 18؉9170, GG vs. GA؉AA, 2 ‫؍‬ 19.9, P ‫؍‬ 0.000008; odds ratio 2.67, 95% CI 1.71-4.16). In situ hybridization (ISH) using the kidney of normal and diabetic mice revealed that ELMO1 expression was weakly detectable mainly in tubular and glomerular epithelial cells in normal mouse kidney and was clearly elevated in the kidney of diabetic mice. Subsequent in vitro analysis revealed that ELMO1 expression was elevated in cells cultured under high glucose conditions (25 mmol/l) compared with cells cultured under normal glucose conditions (5.5 mmol/l). Furthermore, we identified that the expression of extracellular matrix protein genes, such as type 1 collagen and fibronectin, were increased in cells that overexpress ELMO1, whereas the expression of matrix metalloproteinases was decreased. These results indicate that ELMO1 is a novel candidate gene that both confers susceptibility to DN and plays an important role in the development and progression of this disease. Diabetes 54:1171-1178, 2005

To identify genetic elements that might confer susceptibility to diabetic nephropathy, we performed a genome-wide analysis of gene-based single nucleotide polymorphisms (SNPs) in a large cohort of Japanese patients with diabetes. In case-control association studies, patients with type 2 diabetes were divided into two groups, one having retinopathy as well as overt nephropathy and the other (the control group) having diabetic retinopathy but with no signs of renal involvement. Genotyping of these patients at >55,000 SNP loci indicated a gene encoding solute carrier family 12 member 3 (SLC12A3) to be a good candidate for the susceptibility to diabetic nephropathy, in view of a significant association of one landmark SNP located in the 24th intron

Using a large-scale genotyping analysis of gene-based single nucleotide polymorphisms (SNPs) in Japanese type 2 diabetic patients, we have identified a gene encoding neurocalcin delta (NCALD) as a candidate for a susceptibility gene to diabetic nephropathy; the landmark SNP was found in the 3' UTR of NCALD (rs1131863: exon 4 +1340 A vs. G, P = 0.00004, odds ratio = 1.59, 95% CI 1.27-1.98). We also discovered two other SNPs in exon 4 of this gene (+999 T/A, +1307 A/G) that showed absolute linkage disequilibrium to the landmark SNP. Subsequent in vitro functional analysis revealed that synthetic mRNA corresponding to the disease susceptible haplotype (exon 4 +1340 G, +1307 G, +999 A) was degraded faster than mRNA corresponding to the major haplotype (exon 4 +1340 A, +1307 A, +999 T), and allelic mRNA expression of the disease susceptibility allele was significantly lower than that of the major allele in normal kidney tissues. In an experiment using a short interfering RNA targeting NCALD, we found that silencing of the NCALD led to a considerable enhancement of cell migration, accompanied by a significant reduction in E-cadherin expression, and by an elevation of alpha smooth muscle actin expression in cultured renal proximal tubular epithelial cells. We also identified the association of the landmark SNP with the progression of diabetic nephropathy in a 8-year prospective study (A vs. G, P = 0.03, odds ratio = 1.91, 95% CI 1.07-3.42). These results suggest that the NCALD gene is a likely candidate for conferring susceptibility to diabetic nephropathy.

Aims/hypothesis Additional susceptibility loci for type 2 diabetes have been identified by a meta-analysis of genome-wide association studies (GWASs) in European populations. To examine further the roles of these new loci, we performed a replication study for the association of these single-nucleotide polymorphism (SNP) loci with the disease in three independent Japanese populations. Methods We genotyped seven of the 11 SNPs that emerged in stage 2 of the meta-analysis for European GWASs (rs864745 in JAZF1, rs12779790 near CDC123/CAMK1D, rs7961581 near TSPAN8/LGR5, rs4607103 near ADAMTS9, rs10923931 in NOTCH2, rs1153188 near DCD and rs9472138 near VEGFA) for three independent Japanese populations (first set, 1,630 type 2 diabetes patients vs 1,064 controls; second set, 1,272 type 2 diabetes patients vs 856 controls; third set, 486 type 2 diabetes patients vs 936 controls) using a TaqMan assay. The association of the SNP loci in each population was analysed using a logistic regression analysis, adjusting for age, sex and BMI, and the data were evaluated by a meta-analysis. Results A meta-analysis for the three case-control studies identified a nominal association of rs864745 in JAZF1 with type 2 diabetes (OR 1.148, 95% CI 1.034-1.275, p= Diabetologia

Aims/hypothesis Recently, rs10906115 in CDC123/ CAMK1D, rs1359790 near SPRY2, rs1436955 in C2CD4A/ C2CD4B and rs10751301 in ODZ4 were identified as genetic risk variants for type 2 diabetes by a genome-wide association study in a Chinese population. The aim of the present study was to ascertain the role of these four variants in conferring susceptibility to type 2 diabetes in the Japanese population. Methods We genotyped 11,530 Japanese individuals (8,552 type 2 diabetes cases, 2,978 controls) for the above single nucleotide polymorphisms (SNPs) and used logistic regression analysis to determine whether they were associated with type 2 diabetes. Results In accordance with the findings in a Chinese population, rs10906115 A, rs1359790 C and rs1436955 G were found to be risk alleles. Both rs10906115 and rs1359790 were significantly associated with susceptibility to type 2 diabetes in our study (rs10906115 OR 1.15, 95% CI 1.08, 1.22; p=6.10×10 −6 ; rs1359790 OR 1.14, 95% CI