Report of the familial occurrence of systemic lupus erythematosus in male siblings

The occurrence of systemic lupus erythematosus (SLE) is reported in 2 pairs of male siblings. Since the occurrence of idopathic SLE is uncommon in the male, these cases provide additional support to the hypothesis that genetic factors play an important role in pathogenesis. Of additional interest in these patients was the varied clinical manifestations of disease between brothers, suggesting that additional factors govern the clinical expression of this disorder.