High frequency of E148Q sequence variation in children with familial Mediterranean fever in southeast Turkey.

OBJECTIVE The aim of this study was to investigate the spectrum of Mediterranean fever (MEFV) gene mutations and genotype-phenotype correlation in children with familial Mediterranean fever (FMF) in southeast Turkey. METHODS A total of 507 children (274 females) with FMF and MEFV gene mutation(s) were included. A 15-year retrospective evaluation was conducted; parameters analyzed were: age, sex, age at symptoms onset, age at FMF diagnosis, delay between symptoms onset and diagnosis, FMF attack symptoms, and response to colchicine. Disease severity scores were calculated and MEFV mutation analysis was performed via real-time PCR for the 6 most frequent mutations. Children with comorbid diseases or tested negative for MEFV gene mutations were excluded to provide homogeneity. RESULTS A family history of FMF was found in 60.2% (n=305) of patients. The most common symptoms reported for FMF attacks were abdominal pain (98.0%), fever (93.9%) and arthralgia (47.3%); 75.0% of patients (n=380) were heterozygous, 14.2% were homozygous (n=72) and 10.8% were compound heterozygous (n=55).The following MEFV gene mutation alleles were identified: E148Q (40.1%), M694V (25.9%), V726A (15.8%), R761H (7.4%), M680I (6.8%), and P369S (4.1%). The M694V subgroup had the lowest mean age of disease onset and the highest mean disease severity score, whereas the E148Q group had later mean disease onset and the lowest mean disease severity score (p<0.05). CONCLUSION The highest E148Q mutation frequency and milder disease in the course of FMF in our study population may be due to geographic and ethnic background dissimilarities of southeast Turkey.