No association between the type 2 diabetes mellitus susceptibility gene, SLC30A8 and schizophrenia in a Chinese population

Meta-analysis of glucose tolerance, insulin, and insulin resistance in antipsychotic-naïve patients with nonaffective psychosis

BACKGROUND

Some studies have suggested that antipsychotic-naïve patients with nonaffective psychosis (NAP) have glucose intolerance.

AIMS

To conduct a systematic review and meta-analysis of fasting glucose (FG), two hour values in the oral glucose tolerance test (2HG), fasting insulin concentration (INS), and insulin resistance (IR).

METHOD

We identified possibly relevant studies, then selected studies, following usual guidelines, with two authors reviewing the manuscripts. We required studies to include subjects with nonaffective psychosis and control subjects.

RESULTS

There were 911 patients and 870 control subjects in the analysis of FG; their average ages were respectively 28.7 and 29.5years. Significant differences were found for all four variables, with effect size estimates ranging from 0.21 to 0.58.

CONCLUSIONS

As a group, at the time of first clinical contact for psychosis, people with NAP have a slight increase in FG, which most of them maintain in the normal range despite a small increase in IR by secreting additional INS. When faced with a physiological challenge such as a glucose tolerance test or antipsychotics, they are no longer able to maintain a normal glucose concentration.

Type 2 Diabetes Mellitus and the Association of Candidate Genes in Asian Indian Population from Hyderabad, India

INTRODUCTION

Genetic and environmental factors play an important role in susceptibility to type 2 diabetes mellitus (T2DM). Several genes have been implicated in the development of T2DM. Genetic variants of candidate genes are, therefore, prime targets for molecular analysis.

AIM

In this study, we have selected 3 candidate genes, namely, TCF7L2, SLC30A8, and IGF2, for assessing their association with T2DM in an Indian population.

MATERIALS AND METHODS

Five hundred individuals were enrolled in this case-control study- 250 T2DM patients and 250 healthy control individuals. Clinical characteristics were obtained for all subjects, and genotype analysis was performed by PCR-RFLP analysis.

RESULTS

Allele and genotyping frequencies, odds ratios, and 95% confidence intervals were calculated for 3 single nucleotide polymorphisms (SNPs), 1 each from TCF7L2 (rs7903146), SLC30A8 (rs13266634), and IGF2 (rs680) in T2DM patients. The rs7903146 and rs680 polymorphisms were found to be significantly associated with T2DM (p < 0.05), whereas the rs13266634 polymorphism was not (p > 0.05). The multifactor dimensionality reduction method identified the particular polymorphisms associated with an increased risk of disease.

CONCLUSION

The present study indicated that the gene-gene interaction model successfully predicted T2DM risk based on TCF7L2 and SLC30A8 polymorphisms. These results provide strong evidence of independent association between T2DM and the 3 SNPs analysed herein.

Validation of the association of TCF7L2 and SLC30A8 gene polymorphisms with post-transplant diabetes mellitus in Asian Indian population

The rs7903146 and rs13266634 polymorphisms in the TCF7L2 and SLC30A8 genes, respectively, have been reported to be associated with type 2 diabetes. However, little is known about the association of these polymorphisms with post-transplant diabetes mellitus (PTDM). To study this linkage, we determined a distribution of allele and genotype frequencies in Asian Indians. 42 PTDM and 98 non-PTDM subjects were recruited. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect for rs7903146 and rs13266634 polymorphisms. The clinical details and statistical analysis for PTDM and non-PTDM subjects were recorded. Our results observed higher frequencies of the minor alleles in rs7903146 and rs13266634 polymorphisms in the PTDM group compared to the non-PTDM subjects. The allele frequencies also found to be significantly associated with PTDM (rs7903146: T vs C: OR-2.6; (95%CI: 1.2-5.6); p = 0.01; rs13266634: T vs C: OR-2.0; (95%CI: 1.1-3.4); p = 0.01). These findings suggest that rs7903146 and rs13266634 polymorphisms are associated with PTDM in the Asian Indian population despite a relatively small study group.