Allelic variation in BTNL2 and susceptibility to tuberculosis in a South African population

Tuberculosis and sarcoidosis show phenotypic features of granulomatous disease. The bacterium Mycobacterium tuberculosis can induce the expression of the sarcoidosis susceptibility gene BTNL2 in monocyte-derived macrophages. BTNL2 was therefore investigated as a candidate gene for tuberculosis in a case–control association study in the South African Coloured population. We sequenced the coding regions of BTNL2 to detect known and novel polymorphisms and genotyped 18 SNPs in 432 pulmonary tuberculosis cases and 482 controls. We did not find a significant association between the truncating rs2076530 SNP, previously associated with sarcoidosis, and tuberculosis. No association was found between any of the other SNPs studied and disease and none of the estimated haplotypes showed any association with TB. Comparative analyses with the South African data from this study and published data on German and American populations revealed that, for a segment of BTNL2, the admixed, but not stratified, South African population resembles the African-Americans more than white populations.