Genetic variants in leptin: Determinants of obesity and leptin levels in South Indian population

Abstract

The revelation of leptin action mechanisms has led to various attempts to establish the association of polymorphisms in the leptin gene with obesity-related phenotypes. But, outcomes have been contradicting, which made the information on the role of the leptin gene in regulating the mechanism of pathophysiology of obesity inexplicable. Moreover, none of the studies are known to have similar implications on the Indian population. To address such contradictions, our study aims to evaluate the association of leptin gene polymorphism with obesity and leptin levels in a South Indian Population. A total of 304 cases (BMI≥27.5) and 309 controls (BMI≤23) from local inhabitants of Mysore, Karnataka were recruited for the study. The leptin gene variants rs7799039, rs2167270 and rs4731426 independently, as well as in 4 haplotype combinations, were found to be significantly associated with the risk of obesity. An increasing trend in BMI and leptin levels was observed with every addition of A and C minor alleles of exonic variant (rs2167270) and intronic variant (rs4731426) respectively. However, only AA genotype of SNP rs7799039 was positively associated with BMI. None of the SNPs were associated with fat percentage and waist to hip ratio. On a whole, this data suggests that the common polymorphisms in the leptin gene are strong predictors of obesity and leptin levels in South Indians.

Keywords:

• association study
• BMI
• fat percentage
• leptin
• leptin resistance
• obesity

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We are thankful to all subjects in Mysore, Karnataka who voluntarily participated in this study and provided blood samples. We are grateful to Mr S Yaseen Saheb, Dr BV Raviprasad and Dr Jaishankar Rao for their guidance and support throughout the work. We are also thankful to Lions Club Mysore, Dr. Vikas Modi and Dr Ramakrishna of Amritakripa Hospital, Rupanagar, Mysore and paramedical staff for organizing medical camps and extending their valuable help during the collection of samples. Thanks are due to our colleagues Mr Abrar Alam, Mr Ranjith and Dr Pushpa Jogihalli for their sincere involvement at various levels in this project.

Funding

This work is a part of the Anthropological Survey of India's project “People of India: Bio cultural adaptations.” We express our gratitude to the Director Anthropological Survey of India, Ministry of Culture, Government of India, Kolkata for supporting the project financially.