MEFV and Arthritis: Another large Turkish cohort of 3454 patients showed that 88.2% had abdominal pain, 86.7% had a fever, 27.7% had arthritis, 20.2% had chest pain, 23% had myalgia, and 13.1% had erysipelas-like erythema [25].The phenotypic variations among and within different ethnic groups could be explained by a variable MEFV mutation pattern, modifier genes, or environmental and population-specific factors such as demographic history, as well as a complex combination of climatic and geographic features [26].