A variant allele of the Mediterranean-fever gene increases the severity of gout.

BACKGROUND

Gout is a clinical syndrome that occurs as an inflammatory response to increased concentration of uric acid and monosodium urate crystals. Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease with autosomal recessive inheritance. The Mediterranean fever (MEFV) gene is responsible for FMF and encodes pyrin that suppresses the inflammatory response. Most of the FMF-related mutations have been identified in exon 2 (e.g., E148Q and R202Q) and exon 10 (M680I, M694V, M694I and V726A) of the MEFV gene, and each missense mutation is known to increase production of interleukin-1, a proinflammatory cytokine. Our aim was to investigate effects of MEFV variant alleles on the manifestations of gout.

METHODS

Seventy-one patients diagnosed with gout (age: 61.73 ± 11.73 years, F/M: 14/57) and 50 healthy subjects (age: 61.48 ± 11.97, F/M: 10/40) as controls were included in this study.

RESULTS

MEFV variant alleles were found in 24 (33.8%) of the gout patients and in 13 (26%) of the control subjects; the difference was not statistically significant. In the gout patients with a MEFV variant allele, the interval between the first two attacks was shorter (P = 0.014), and the platelet count was higher (P = 0.026), compared to the patients without a variant allele. In addition, the patients with a MEFV variant allele showed the higher incidence of tophus (8.5% vs. 1.4%) (P = 0.005) and the higher number of attacks per year (P = 0.001).

CONCLUSION

We propose that a variant allele of the MEFV gene may be responsible for the severity of gout.