Abstract
Two classical autoimmune polyendocrine deficiency syndromes with heritable tendencies are described, Type 1 diabetes mellitus being associated with the Type 2 polyendocrine deficiency syndrome (Schmidt's syndrome). A man with Type 1 diabetes mellitus is described who developed an unusual combination of five autoimmune conditions (myasthenia gravis, Addisonian pernicious anaemia, adrenalitis and thyroiditis) which did not fit into the Type 1 or Type 2 classical polyendocrine deficiency syndromes. This suggests that the autoantibody, biochemical and haematological screening of affected individuals and their relatives should be extended to anticipate a wider range of potential autoimmune conditions.