rs6127698 polymorphism in the MC3R gene and susceptibility to multifocal tuberculosis in southern Chinese Han population

Abstract

Objective: To investigate the relationship between melanocortin-3 receptor (MC3R) gene polymorphism and tuberculosis (TB) susceptibility in Han population in southern China.

Methods: A total of 341 patients with TB (173 with pulmonary TB and 168 with multifocal TB) and 359 healthy controls were enrolled. Genotyping was performed by PCR and DNA sequencing, and detection of protein was performed by western blot.

Results: The distributions of genotype and allele frequencies of rs6127698 differed significantly between the pulmonary and multifocal TB groups, and between the multifocal TB and control groups. The GG genotype was significantly more common among multifocal TB patients than among pulmonary TB patients (P = .009) and those in the control group (P = .001) under the recessive model. GG+GT genotype was more common in multifocal TB than in pulmonary TB (P < .01) and control group (P < .01) under the dominant model. G allele was more common in multifocal TB than in pulmonary TB (P < .0167) and control group (P < .0167). Patients with multifocal TB had an increased expression of MC3R protein than healthy controls (P < .05).

Conclusions: In the southern Chinese Han population, the MC3R rs6127698 polymorphism, which accompanying an increased expression of MC3R protein,was associated with susceptibility to multifocal TB. Presence of the G allele increased the risk of developing multifocal TB.

Keywords: Gene polymorphism; MC3R; Multifocal tuberculosis.