Sickle cell trait: Individuals who carry one copy of the sickle cell gene have some resistance to malaria, a serious infectious disease caused by Plasmodium parasites. Cystic fibrosis carriers: People who carry one copy of the gene causing cystic fibrosis may have increased resistance to certain bacterial infections, such as those caused by Pseudomonas aeruginosa. Genetic variations in the HLA complex: These variations can affect how the immune system recognizes and responds to pathogens, influencing susceptibility to diseases like tuberculosis.
