Association Between Keratoconus and Familial Mediterranean Fever in Turkey.

Purpose: To evaluate the association between familial Mediterranean fever (FMF) and keratoconus (KC).
Methods: This retrospective case-control study was performed to compare the prevalence of KC in patients with FMF with the corresponding prevalence in control patients without FMF referred to Genetic Diagnostic Center at Diskapi Yildirim Beyazit Training and Research Hospital from June 2012 to June 2015. We included all 100 patients with FMF. Each FMF-affected patient was matched to 3 controls.
Results: None of the patients in the control group (0%, 0/300) had KC, whereas 4 of 100 patients with FMF (4%) had KC (P < 0.004). Three of 33 patients with a homozygous mutation (9.1%) (M694V/M694V in 2 cases and M680I/M680I in 1 case) and 1 of the 46 patients with a compound heterozygous mutation (2.2%) (M694V/M680I) had KC, whereas none of the 21 patients with a heterozygous mutation (0%) had KC. All patients with KC were women, and mean age was 40.8 years (range, 30-51). Although 1 of the 4 patients with KC had hypertension and type 2 diabetes mellitus, the other 3 patients did not have any systemic illness except FMF. When we compared the prevalence of KC in patients with FMF (4%) with the highest prevalence of KC reported in the literature (0.2%), FMF was a predisposing factor to develop KC [odds ratio: 18.1 (95% CI: 11.9-27.5)] especially in patients with a homozygous mutation [odds ratio: 43.4 (95% CI: 28.6-65.7)].
Conclusions: Mediterranean fever (MEFV) gene mutations, particularly in homozygous mutations of the MEFV gene, may be a predisposing factor in the development of KC.