CDK4 IVS4-nt40G-->A SNP and type 2 diabetes in Italians.

As cyclin-dependant kinase 4 (CDK4) regulates beta cell proliferation, it may confer T2D risk. We tested the CDK4 IVS4-nt40A-->G SNP for association with T2D in Italians (230 cases, 204 control subjects) and excluded a role of the variant in our dataset.

CHOP 5'UTR-c.279T>C and +nt30C>T variants are not associated with overweight condition or with tumors/cancer in Italians - a case-control study.

BACKGROUND: Type 2 diabetes (T2D) is associated with obesity and has been shown recently to be associated with tumors/cancer. HNF1-beta and JAZF1 genes are associated with T2D and prostate cancer. We have previously shown that CHOP 5'UTR-c.279T>C and +nt30C>T haplotype variants contribute to T2D. CHOP deficiency causes obesity in mice, thus CHOP gene variants may contribute to human obesity. Furthermore, CHOP mediates apoptosis and is implicated in cancer pathogenesis. Hence, we aimed at identifying any potential association of CHOP 5'UTR-c.279T>C and +nt30C>T genotypes and corresponding haplotypes with overweight condition/pre-obesity and tumors/cancer in an Italian dataset. METHODS: We recruited from Italy 45 overweight subjects (body mass index (BMI) >or= 25) and 44 control subjects (BMI < 25) as well as 54 cases with at least one cancer or at least one tumor and 43 control subjects without tumors/cancer from the general population. We excluded allelic departure from Hardy-Weinberg equilibrium in cases and control subjects, separately. RESULTS: We assessed the power to detect risk odds ratios by association tests in our datasets. We tested the hypothesis of association of CHOP 5'UTR-c.279T>C and +nt30C>T genotypes and haplotypes with tumors/cancer and, separately, with overweight condition. Both associations were not significant. CONCLUSION: From our study, we may conclude that CHOP 5'UTR-c.279T>C and +nt30C>T genotypes and corresponding haplotypes are not associated with tumors/cancer and pre-obesity. However, more studies are warranted to establish the role of CHOP variants in tumor/cancer predisposition and in overweight condition.

Linkage studies for T2D in Chop and C/EBPbeta chromosomal regions in Italians.

The genes causing type 2 diabetes (T2D), a complex heterogeneous disorder, differ and/or overlap in various populations. Among others there are two loci in linkage to T2D, the chromosomes 20q12-13.1 and 12q15. These two regions harbor two genes, C/EBPbeta and CHOP, which are excellent candidate genes for T2D. In fact, C/EBPbeta protein cooperates with HNF4alpha (MODY1, monogenic form of diabetes) and 1alpha (MODY3, monogenic form of diabetes). C/EBPbeta mediates suppression of insulin gene transcription in hyperglycemia and may contribute to insulin-resistance. It interacts in a complex pathway with the CHOP protein. CHOP may play a role in altered beta-cell glucose metabolism, in beta-cell apoptosis, and in lack of beta-cell replication. Thus, both C/EBPbeta and CHOP genes may independently and interactively contribute to T2D. The chromosomal regions targeting C/EBPbeta and CHOP genes have never been previously explored in T2D. We planned to identify their potential contribution to T2D in Italians. We have genotyped a group of affected siblings/families with both late- and early-onset T2D around the C/EBPbeta and the CHOP genes. We have performed non-parametric linkage analysis in the total T2D group, in the late-onset and the early-onset group, separately. We have identified a suggestive linkage to T2D in the CHOP gene locus in the early-onset T2D group (P = 0.04). We identified the linkage to T2D in the chromosome 12q15 region in the early-onset T2D families and specifically target the CHOP gene. Our next step will be the identification of CHOP gene variants, which may contribute to the linkage to T2D in Italians.