How is etiology of FMF?

Recessive genetic disease missense and non sense mutations of MEFV gene in short arm of chrm 16, codes for pyrin/marenostrin protein, more than 310 sequence variants in MEFV gene has been identified no all disease phenotype, Homo M694V (valine for methionine) experience more severe disease and develop amyloidosis, V726A (alanine for valine) lower risk of amyloidosis.