[The role of human genetic factors in susceptibility to tuberculosis]

Tuberculosis has been one of the most important illnesses in the history of the world, but it was never understood why only some people, and not others, develop the disease. It was assumed that human genetic factors play a role in susceptibility, but until the advent of molecular markers, it was never possible to convincingly separate inheritance from the compounding factors of environment and exposure to the bacillus. In recent years particular polymorphisms of several human genes have been shown to be correlated with susceptibility to TB: NRAMP1, Vitamin D receptor, Interferon gamma receptor, IL-12 and its receptor, several HLA haplotypes and there are probably several others that will be discovered. Nevertheless, no single gene appears to play a dominant role in the total TB burden of any population, and exposure of the individual to the bacillus and the environment and nutritional state of the individual also seem to play an important role in determining who will develop the disease.