Fine-mapping analysis of a chromosome 2 region linked to resistance to Mycobacterium tuberculosis infection in Uganda reveals potential regulatory variants.

Tuberculosis (TB) is a major public health burden worldwide, and more effective treatment is sorely needed. Consequently, uncovering causes of resistance to Mycobacterium tuberculosis (Mtb) infection is of special importance for vaccine design. Resistance to Mtb infection can be defined by a persistently negative tuberculin skin test (PTST-) despite living in close and sustained exposure to an active TB case. While susceptibility to Mtb is, in part, genetically determined, relatively little work has been done to uncover genetic factors underlying resistance to Mtb infection. We examined a region on chromosome 2q previously implicated in our genomewide linkage scan by a targeted, high-density association scan for genetic variants enhancing PTST- in two independent Ugandan TB household cohorts (n = 747 and 471). We found association with SNPs in neighboring genes ZEB2 and GTDC1 (peak meta p = 1.9 × 10-5) supported by both samples. Bioinformatic analysis suggests these variants may affect PTST- by regulating the histone deacetylase (HDAC) pathway, supporting previous results from transcriptomic analyses. An apparent protective effect of PTST- against body-mass wasting suggests a link between resistance to Mtb infection and healthy body composition. Our results provide insight into how humans may escape latent Mtb infection despite heavy exposure.