Familial clustering of malignant astrocytomas.

Three of 32 consecutive patients with astrocytomas enrolled in an experimental chemotherapy protocol had at least one first degree relative with an astrocytoma. These patients did not have family members with an excess of malignancies, known exposure to a specific environmental factor, or a recognized neurocutaneous syndrome. In all three families, the illnesses temporally overlapped and the age of the patients affected in the second generation was less than those in the first generation. An estimation of the probability of developing astrocytomas in families with one affected individual strongly suggests a familial effect. Our observations, coupled with other cases reported in the literature, suggest that familial astrocytomas occur more frequently than is currently recognized. Identification and careful study of such families may provide important clues to the etiology of these malignancies.