Is TB Genetic?
No, tuberculosis (TB) is not solely genetic, but genetic factors significantly influence susceptibility to the disease. While TB is primarily an infectious disease caused by the bacterium Mycobacterium tuberculosis, a person's genetic makeup plays a crucial role in determining their likelihood of developing the illness after exposure.
Research strongly suggests a genetic component in TB susceptibility. Twin studies, for example, estimate heritability of susceptibility to TB as high as 80% (Diehl and Von, 1936; Kallmann and Reisner, 1943; https://elifesciences.org/articles/84394). This means that a significant portion of the variation in susceptibility among individuals can be attributed to their genes.
Several studies have identified specific genes and genetic variations linked to increased or decreased risk of developing TB. For example, variations in the TYK2 gene have been associated with heightened TB risk, particularly in individuals with two copies of a specific variation ( https://www.rockefeller.edu/news/24686-study-identifies-genetic-mutation-responsible-tuberculosis-vulnerability/, https://www.genengnews.com/news/tuberculosis-susceptibility-could-be-in-your-genes/). This highlights that while infection is necessary, genetic predisposition heavily influences the outcome.
It's important to understand that only a fraction of individuals exposed to M. tuberculosis develop clinical TB (https://pmc.ncbi.nlm.nih.gov/articles/PMC4024222/). This underscores the complex interplay between the infectious agent and the host's genetic background. The nature of this host-pathogen interaction undeniably includes a genetic component (https://en.wikipedia.org/wiki/Genetics_of_tuberculosis).
Furthermore, research indicates that TB is a "genetically primed and determined infectious disease" (https://pmc.ncbi.nlm.nih.gov/articles/PMC6503728/), emphasizing the vital role genetics play in shaping an individual's response to infection.
Conclusion
In summary, while TB infection is caused by a bacterium, genetic factors significantly influence individual susceptibility. This means that while exposure is a necessary factor, the development of the disease is heavily influenced by an individual’s genetic makeup.
