Musculoskeletal manifestations in patients with familial Mediterranean fever and its relation to different genotypes

To describe various musculoskeletal manifestations in patients with Familial Mediterranean Fever (FMF) and their relation to different genotypes. Fifty-four FMF patients were included. All patients underwent detailed history taking, physical examination, and Mediterranean Fever (MEFV) gene mutation analysis using real-time polymerized chain reaction (PCR). The median age was 25 years (6–53 years). 35 were females and 19 males (F:M 1.84:1). 61.1% of patients developed symptoms before the age of 20 years. MEFV gene mutations were detected in 83.3% of cases with M694I mutation the most frequent. Musculoskeletal manifestations were the most frequent feature (92.6%). Arthralgia, myalgia and mechanical back pain were significantly more frequent during attacks. Arthritis was found in 22.2% of patients during attacks and 16.7% between attacks. No significant association was found between mutation positivity and the presence of arthralgia, myalgia, or arthritis during attacks. During attacks, knee joint pain was significantly more frequent in homozygous patients. Between attacks, shoulder joint pain was significantly more prevalent among homozygous patients. Patients with M694V mutation showed higher frequency of arthritis during attacks (50%) and higher prevalence myalgia (83.3%). Between attacks myalgia was significantly more frequent among M694V-positive patients compared with M694V-negative patients. Musculoskeletal manifestations are frequent clinical features in FMF patients. While MEFV mutations are common, type of gene mutation alone do not predict clinical manifestations, except for an association between homozygosity and specific joint involvement and a higher frequency of myalgia among M694V mutation positive patients.