IL21R and tuberculosis: Six QTLRs harbor seven genes that have been already associated with susceptibility/resistance to TB: QTLR_12 on BTA 1 (CD80), QTLR_25 on BTA3 (CTSS), QTLR_26 on BTA 3 (FCGR1A), QTLR_127 on BTA 23 (HFE), QTLR_133 on BTA 25 (IL21R), and QTLR_152 on BTA 29 (ANO9 and SIGIRR).