Mitochondrial DNA haplogroup C4 can increase the risk of active tuberculosis disease in Southwest China.

Tuberculosis (TB) remains a serious health problem worldwide. Host genetic factors are reported to be correlated with tuberculous infection. However, few mitochondrial genetic studies of TB patients have been carried out. To investigate the role of mitochondrial DNA (mtDNA) in tuberculous infection. We recruited 243 TB patients and 261 normal controls (NCs) to compare their mtDNA haplogroups and copy numbers. The frequency of mtDNA haplogroup C4 was significantly higher in TB patients (7%) than in NCs (2.8%, = 0.042). However, this difference disappeared when TB patients were separated into male and female groups and compared with sex-matched NCs. When TB patients were divided into five subgroups for further analyses, the mtDNA haplogroup C4 showed different frequencies among the five subgroups. The frequency of the haplogroup C4 was much lower in the pulmonary TB (pTB) and pleural TB (plTB) group (1.4%) than in the non-pTB and plTB group (9.3%, = 0.027). mtDNA copy numbers were significantly higher in TB patients than in NCs (99.09 ± 54.54 vs. 73.90 ± 43.92; < 0.0001); results in male/female/total TB patients and matched NCs were similar. mtDNA haplogroups and copy numbers were found to have an important role in active TB disease. .