Causes of chronic lymphocytic leukaemia

The cause of CLL is not known, but research is going on all the time to try to find out. Like other leukaemias, it is not infectious and cannot be passed on to other people.

In most people, CLL is not caused by an inherited faulty gene, so other members of their family are not likely to develop CLL. However, in some cases (about 1 in 10), other family members also have CLL. This is known as familial CLL. It is not yet known why this occurs, but research is trying to find out.

CLL occurs more often in men than women, but the reason for this is not known.