Association of ACE I/D gene polymorphism and related risk factors in impaired fasting glucose and type 2 diabetes: a study among two tribal populations of North-East India.

BACKGROUND: Type 2 diabetes is a serious public health concern in India, even the indigenous tribal populations are not left unaffected. The present study aims to understand the association of major risk factors i.e. obesity, hypertension, dyslipidemia, ACE I/D polymorphism with impaired fasting glucose (IFG) and type 2 diabetes (T2D) among two different Mendelian populations of North East India. METHODS: Demographic, somatometric, physiological variables along with fasting blood samples were collected from 609 individuals. The participants were screened for ACE I/D polymorphism. RESULTS: ACE I/D polymorphism was found to follow HWE among Liangmai tribe but not among Mizo tribe. Distribution of DD genotype/D allele was found to be significantly higher for T2D among Mizo tribe. Significant association were observed between DD genotype/D allele of ACE I/D polymorphism and TC as well as LDL with both IFG and T2D only in Mizo tribe. CONCLUSIONS: The present study is an example of gene-environment interaction where DD genotype or D allele and dyslipidemia (high TC and high LDL) are posing risk for IFG and T2D both independently and in combination only among Mizo tribe with relatively less physical activity attributed to their residence in less hilly terrain however Liangmai tribe which resides in high hilly terrain shows no such association.

Obesity, dyslipidaemia and candidate gene polymorphisms: a cross-sectional study among the Liangmai and Mizo tribes of Manipur, India.

BACKGROUND: The prevalence of obesity and dyslipidaemia was observed to be increased among the tribal populations, due to globalization. MATERIALS AND METHODS: In the present study, data on demographic, somatometric and blood samples were collected from 613 participants of both sex, age 18-60 years, further lipid profiling and genotyping was executed. Multifactor dimensionality reduction (MDR) software was used for gene-gene interactions analysis. RESULTS: Significantly differences were observed with respect to the general characteristic and selected gene polymorphisms in both the tribes. Among the Liangmai tribe, MC4R gene was found to pose significant decreased risk for waist-height ratio (WHtR) (OR = 0.56; 95% confidence interval (CI)= 0.32-0.99; p value = .04) and HDL (OR = 0.58; 95% CI = 0.36-0.92; p value = .02). Similar trends of significant decreased risk (OR = 0.39; 95% CI = 0.20-0.76; p value=.006) for BMI were observed among the Mizo tribe. The gene-gene interaction revealed the combined model of FTO+MC4R genes shows an increased risk for BMI in both the tribes. The independent significant increased risk posed by FTO gene was moderated by interaction with MC4R gene. CONCLUSIONS: The observed differences can possibly attribute to both their respective ancestries resulting in different gene pools and the physical environment. The results of the study highlight the importance of gene-gene and gene-environment interactions in adverse phenotype groups.KEY MESSAGEAmong the tribal population, the prevalence of obesity and dyslipidaemia has been increased.Differential distribution and associations of selected markers hint towards differential genetic architecture in these populations.MC4R rs17782313 polymorphism was found to show a significantly decreased risk for WHtR and low HDL among the Liangmai tribe and BMI among the Mizo tribe.Significant increased risk posed by FTO rs9939609 gene polymorphism was moderated by the interaction with MC4R rs17782313.

Differential distribution and association of FTO rs9939609 gene polymorphism with obesity: A cross-sectional study among two tribal populations of India with East-Asian ancestry.

The fat mass and obesity associated (FTO) rs9939609 gene polymorphism is most widely studied in terms of obesity in various populations. Recently, the prevalence of obesity has been reported to be very high among the North-Eastern State of India. The major aim of the present study is to understand the extent of FTO rs9939609 gene polymorphism and its association with obesity among the two North-East Indian tribal populations with similar East Asian ancestry. Somatometric data and fasting blood sample were collected from 521 tribal individuals (258 Liangmai and 263 Mizo) of Manipur after obtaining written informed consent. Genotyping of FTO rs9939609 single nucleotide polymorphism (SNP) was done using restriction fragment length polymorphism method for PCR-amplified fragments. Both the presently studied populations were not following Hardy-Weinberg law. The prevalence of obesity and minor allele frequency of FTO rs9939609 polymorphism was found to be significantly higher among the Mizo tribe compared to that of Liangmai. The selected polymorphism was found to be significantly associated with obesity (BMI) only among the Liangmai tribe (Odds ratio-3.0; 95% CI-1.4, 6.4; p-0.003), after adjusting for age and occupation. Age-cohort wise distribution and absolute fitness analysis indicated the lower fitness of minor allele in the higher age group among the Liangmai tribe. To the best of the author's knowledge this is the first study, associating FTO rs9939609 gene polymorphism and obesity in the North-eastern Indian tribal populations with East-Asian ancestry. This study revealed the FTO rs9939609 polymorphism is observed to be associated with obesity only among the Liangmai tribe not among the Mizo tribe. The differential distribution and association observed in the two selected tribes, inhabited in a similar geographical region, could be attributed to differences in their migratory histories in terms of both route and time of settlement.