Preliminary Evaluation for the Development of a Scoring System to Predict Homozygous M694V Genotype in Familial Mediterranean Fever Patients: A Single-Center Study.

Objective: The aim of this study was to identify key parameters of a scoring system to be developed to predict the homozygous M694V genotype in patients clinically diagnosed with familial Mediterranean fever.

Methods: This study was a cross-sectional analysis of 472 pediatric familial Mediterranean fever patients with a homozygous genotype on exon 10, followed at our tertiary pediatric rheumatology clinic between June 2016 and June 2023. The patients were categorized into 2 groups based on their genotypes: group 1 comprised 402 patients (85.2%) with the homozygous M694V genotype, whereas group 2 consisted of 70 patients (14.8%) with other homozygous genotypes. Demographic information, clinical manifestations, MEFV (Mediterranean fever) gene variant analysis, and treatment responses were recorded from the patients' medical charts.

Results: The odds ratios for age at disease onset, arthritis, and chest pain were 0.892 (95% confidence interval [CI]: 0.832-0.958, p = 0.002), 2.565 (95% CI: 1.109-5.934, p = 0.028), and 2.351 (95% CI: 1.123-4.922, p = 0.023), respectively. A total of 60.7% of patients in group 1 had arthralgia, and 25% had erysipelas-like erythema, with these percentages were higher in group 1 compared with group 2 (p = 0.002, p = 0.001, respectively). Protracted febrile myalgia syndrome was detected in 1.5% of patients, all of whom had homozygous M694V genotype. Colchicine resistance was detected in 13.3% of patients, and all had homozygous M694V genotype.

Conclusions: This preliminary evaluation identified key parameters for a scoring system designed to predict the homozygous M694V genotype. A multicenter national study will further refine these parameters and develop the scoring system, which will aid clinicians in disease prognosis and therapeutic decision-making.