Risk factors for developing CLL can include inherited, or genetic, traits and exposure to cancer-causing agents in the environment. There is only a very small chance that a person who has one of the few known risk factors for CLL will develop the disease.
People who have a first-degree relative -- a parent, child, or sibling -- with CLL have a two- to four-fold increased risk of developing CLL. Most of the people who develop CLL, however, do not have a relative with the disease.
CLL may also be linked to exposure to Agent Orange, a chemical used widely during the Vietnam War. Researchers at the Institute of Medicine, an arm of the National Academy of Sciences, have found that veterans who served in Vietnam have a heightened risk of CLL. Agent Orange exposure is also associated with higher rates of lymphoma, multiple myeloma, and other medical conditions.
Scientists know that most cases of leukemia are associated with specific gene mutations, but in most cases, it is not clear what causes those mutations.
