Final answer:
Pernicious anemia is caused by a deficiency of vitamin B12.
Step-by-step explanation:
Pernicious anemia is caused by a deficiency of vitamin B12. It is a condition where the body is unable to absorb enough vitamin B12 from the food you eat, leading to low levels of this important vitamin. Vitamin B12 is mainly found in animal products, so vegans and vegetarians are at higher risk of developing pernicious anemia. This condition can also occur in individuals with Crohn's disease, surgical removal of the intestines or stomach, intestinal parasites, and AIDS.