Familial erythroleukemia: four cases of the Diguglielmo syndrome in close relatives.

Erythroleukemia was diagnosed in three brothers during a 6-month period in 1976. A son of one leukemic had died 5 years earlier with erythroleukemia. First-degree relatives of these men were evaluated in an attempt to identify contributing factors. Twenty-four relatives have been studied. Immunoglobulin M was elevated in 14 of 16 persons (mean, 352.8 mg/dl; normal, less than 145 mg/dl; P less than .001). This was neither a monoclonal protein nor rheumatoid factor. Age-dependent red cell enzymes were increased. Erythrocyte hexokinase was markedly increased in 23 of 24 persons (mean, 35.05 units/100 ml RBC; normal, less than 18 units; P less than .001). Evidence for a hemolytic state was absent. Bone marrow samples in 8 first-degree relatives were normal. Cytogenetics were normal in 18 relatives. One leukemic exhibited hypoploidy and a marker chromosome. The association of an immunoglobulin abnormality and enzymopathy in the leukemics and relatives alike suggests a hereditary susceptibility to the development of erythroleukemia. The exact link is not identified.