Familial chronic lymphocytic leukemia.

Familial aggregation of chronic lymphocytic leukemia (CLL) has been observed more frequently than familial aggregation of any other type of oncohematologic disorder. The presence of cells with a CLL-like immunophenotype (CLL-like cells) was recently documented in 13.5% healthy first-degree relatives of CLL patients. We present a family with CLL in which 2 brothers, a sister and their mother were affected.