Co-existence of Hashimoto's thyroiditis with familial Mediterranean fever: is there a pathophysiological association between the two diseases?

Familial Mediterranean fever is an autosomal recessive disease characterized by periodic attacks of fever and polyserositis, while Hashimoto's thyroiditis is the most common cause of hypothyroidism. We suggest that common autoimmune mechanisms may underlie both disorders, describe their clinical co-existence in a patient, and discuss a possible causal link between them.