The identified risk factors which are: age 21–50 years, HIV coinfection, low BMI of ≤18.5 kg/m2, low CD4 cell count ≤350 cells/mm3, previous history of TB disease, smoking (especially ex-smokers), and substance abuse, should help target the high risk groups among inmates that must be closely monitored for developing TB. The gene discussed is CD4; the disease is substance abuse.