Increased incidence of hematologic malignancies in first-degree relatives of patients with chronic lymphocytic leukemia.

Cases of leukemia in more than one family member occur rarely. Family members of patients with chronic lymphocytic leukemia (CLL) may, however, be at increased risk of hematologic malignancy. The charts of all patients with CLL (29) seen by the author from 1987 through 1989 were reviewed and living patients specifically questioned about family history of malignancy. Ten of the 29 (34%) had a first-degree relative with a hematologic malignancy. Three patients had a first-degree relative with CLL including a pair of identical twins. Two additional patients had a spouse with a lymphoid malignancy. No differences were found in serum immunoglobulin levels between those patients with a family history of hematologic neoplasia and those without. The lymphocytes of the majority of patients with a family history of hematologic neoplasia (60%) expressed kappa light chains as did those without (70%). An increased incidence of lymphoid malignancy has been reported in western Ashkenazi Jews and in particular those of Russian descent. The majority of our cases were of Jewish origin and came from Eastern Europe. Seven of 10 patients with a family history of hematologic neoplasia were from Eastern Europe. In contrast only one of three patients with CLL who had a first-degree relative with CLL was of Jewish origin.