The Clinical Characteristics and Prognosis of Exon 2 Mutations in Familial Mediterranean Fever

Objective: It is unclear whether exon 2 mutations are variations or a mutations that causes the disease. This study aimed to evaluate the clinical features and prognosis exon 2 mutations in Familial Mediterranean Fever. Methods: The clinical features, disease severity and prognosis of all patients with at least one exon 2 mutations were evaluated retrospectively. These data were compared seperately for homozygous (Group 1), heterozygous (Group 2), compound heterozygous (Group 3), and complex alleles (Group 4), and the data were compared by grouping patients into those with and without exon 10 mutations. Results: There were a total of 119 patients with exon 2 mutations, including 11.7% in Group 1, 36.1% in Group 2, 21.8% in Group 3, and 30.2% in Group 4 were similar in terms of demographic data, clinical characteristics, and disease course. When compared patients with exon 10 mutations (+) to those with exon 10 mutations (-), the exon 10 mutations (+) group had a higher presence of chest pain (100%, p=0.02) and a significantly higher mean Pras severity score (6.66±1.87, 6.01±1.40; p=0.02). Additionally, a higher number of patients with exon 10 mutation (-) achieved remission with treatment (76 (67.9%), 36 (32.1%); p=0.03). Conclusion: Exon 2 mutations have a milder course and higher remission rates but they should be considered as Familial Mediterranean Fever disease because of their similar clinical presentation and response to colchicine treatment with exon 10 mutations. Early treatment and close follow-up should be performed.