Clinical significance of MEFV gene variation R202Q.

Background: The aim of this study was to evaluate the phenotypic features and the clinical significance of the R202Q mutation of the MEFV gene.

Methods: We retrospectively reviewed the medical records of Familial Mediterranean Fever patients with M694V/- and M694V/R202Q mutations. We compared the patients regarding disease severity, symptoms, age at the onset of symptoms, gender, consanguinity, and family history.

Results: Twenty-one patients (9 males, 12 females) had compound heterozygote mutation (M694V/R202Q), and 37 patients (23 males, 14 females) had M694V/- mutation. The mean age of the patients at the time of diagnosis was 7.3 ± 4.3 and 9.2 ± 3.7 years. The rate of arthritis was significantly higher in patients with M694V/R202Q heterozygote mutation than those with M694V/- heterozygote mutation (76.2% vs 32.4%; p =  < 0.001). The mean severity score was higher in M694V/R202Q heterozygote group although it did not reach statistical significance (8.43 ± 1.69 vs 7.49 ± 1.50; p = 0.082). However, the rate of having a high severity score was significantly higher in the M694V/R202Q mutation group than in the other group (47.6% vs 21.6%, respectively; p = 0.039). The rate of arthritis was significantly higher in patients with M694V/R202Q heterozygote mutation than those with M694V/- heterozygote mutation (76.2% vs 32.4%; p =  < 0.001).

Conclusion: Our finding supports the possibility that R202Q may be pathogenic rather than a variation. We found that the R202Q mutation is associated with the inflammatory phenotype of FMF; hence, the typical clinical findings of FMF especially arthritis can be observed in patients with compound mutation including R202Q. Key Points • We found that the R202Q mutation is associated with the inflammatory phenotype of FMF • The patients with the R202Q mutation had a greater rate of arthritis symptoms.