Familial Mediterranean Fever (FMF) is an autoinflammatory disorder caused by a mutation in the MEFV gene, which codes for the pyrin protein found in white blood cells. This genetic alteration can disrupt the function of the pyrin protein, leading to dysregulation of the immune system and recurrent inflammation. Research suggests that MEFV gene mutations may also play a role in the development of other autoimmune conditions, including rheumatoid arthritis.