Pyrin (also known as MEFV) associates with microtubules and co-localises with actin. It is regulated in response to inflammatory mediators. In humans, it is expressed in peripheral blood leukocytes. Mutations in the pyrin gene cause familial Mediterranean fever, autosomal recessive (ARFMF) and familial Mediterranean fever, autosomal dominant (ADFMF). Familial Mediterranean fever is characterised by recurrent episodes of fever, which are independent of any bacterial or viral infections.