Association of Uncoupling Protein 1 (UCP1) gene polymorphism with obesity: a case-control study

Shahanas Chathoth,Amein Al Ali,Khandaker Ahtesham Ahmed,Sadananda Acharya,Chittibabu Vatte,Mona H Ismail,Zhara Al Ali,Cyril Cyrus,Aisha Mohammed Al Barqi

doi:10.1186/s12881-018-0715-5

Abstract

BackgroundObesity is one of the main causes of morbidity and mortality worldwide. More than 120 genes have been shown to be associated with obesity related phenotypes. The aim of this study was to determine the effect of selected genetic polymorphisms in Uncoupling protein 1 (UCP1) and Niemann-Pick C1 (NPC1) genes in an obese population in Saudi Arabia.MethodsThe genotypes of rs1800592, rs10011540 and rs3811791 (UCP1 gene) and rs1805081 and rs1805082 (NPC1 gene) were determined in a total of 492 subjects using TaqMan chemistry by Real-time PCR. In addition, capillary sequencing assay was performed to identify two specific polymorphisms viz., rs45539933 (exon 2) and rs2270565 (exon 5) of UCP1 gene.ResultsA significant association of UCP1 polymorphisms rs1800592 [OR, 1.52 (1.10–2.08); p = 0.009] was observed in the obese cohort after adjusting with age, sex and type 2 diabetes. Further BMI based stratification revealed that this association was inconsistent with both moderate and extreme obese cohort. A significant association of UCP1 polymorphisms rs3811791 was observed only in the moderate-obese cohort [OR = 2.89 (1.33–6.25); p = 0.007] but not in the extreme-obese cohort indicating an overlying genetic complexity between moderate-obesity and extreme-obesity. The risk allele frequencies, which were higher in moderate-obese cohort, had abnormal HDL, LDL and triglyceride levels.ConclusionThe rs1800592 and rs3811791 of UCP1 gene are associated with obesity in general and in the moderate-obese group in particular. The associated UCP1 polymorphisms in the moderate-obese group may regulate the impaired energy metabolism which plays a significant role in the initial stages of obesity.

Highlights

Obesity is one of the main causes of morbidity and mortality worldwide
The allele frequencies of the Single Nucleotide Polymorphism (SNP) rs1800592, rs10011540, rs3811791 (UCP1) and rs1805081 and rs1805082 (NPC1) are listed in Table 2 and genotype frequencies are mentioned in Additional file 1: Table S1
The mutant allele G of SNP rs1800592 on Uncoupling protein 1 (UCP1) showed a significant association with obesity [OR, 1.52 (1.10–2.08); p = 0.009]

Summary

Introduction

Obesity is one of the main causes of morbidity and mortality worldwide. More than 120 genes have been shown to be associated with obesity related phenotypes. The aim of this study was to determine the effect of selected genetic polymorphisms in Uncoupling protein 1 (UCP1) and Niemann-Pick C1 (NPC1) genes in an obese population in Saudi Arabia. Several studies have reported that polymorphisms of the UCP1 gene such as, g.-3826A > G (rs1800592), g.-1766A > G (rs10011540) and g.-112A > C (rs3811791) in the promoter region, and p.Ala64Thr (rs45539933) and p.Met299Leu (rs2270565) in the codon region are associated with obesity and T2DM [10,11,12,13,14,15]. It has been reported that rs1805081 (p.His215Arg) and rs1805082 (p.Ile858Val) polymorphisms of the NPC1 gene are associated with early-onset and morbid adult obesity in a European population and Chinese children [19,20,21]. A Genome Wide Association Study conducted on Mexican children found a significant association of risk allele NPC1 rs1805081 with increased fasting glucose levels and decreased fasting serum insulin levels [22]

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