Myalgia as a symptom of familial Mediterranean fever in children

We read the article entitled Familial Mediterranean fever gene mutation frequencies and genotype–phenotype correlations in the Aegean region of Turkey prepared by Ozalkaya et al. [1]. The results will be more rational while describing the characteristics of an inherited disease in a certain geographic region, if the data obtained from all or near all of the patients in that region is given. As being another center in the Aegean Region, serving children with familial Mediterranean fever (FMF), we compared our results with those of the above study and aimed to evaluate their consistency. There were 172 patients (M/F: 89/83) being followed up in our center with the diagnosis of FMF based on Tel Hashomer criteria. The mean ages at the onset of symptoms and at the time of diagnosis were months (1–292) and 115 § 63 months (2–612), respectively. Clinical features of the patients are shown in Table 1. MEFV gene analysis including 12 most frequent mutations seen in Turkish people was performed in 84 patients. The results are shown in Table 2. Most frequent mutation was M694V that was present in 60 (71.4%) patients. Three cases with amyloidosis had MEVF gene analysis; two cases were homozygous and one case was heterozygous for M694V mutation. There were 6 patients with none of the twelve mutations screened. The data of our cases from the same geographic region including the mean age of the patients at the diagnosis and at onset of the symptom, frequency of symptoms except for myalgia and genotypes of the patients were found similar to those described in the study of Ozalkaya et al. Although from the same region, myalgia was signiWcantly more frequent among our patients than those in the study of Ozalkaya et al. They categorized their patients due to reliability of diagnosis as deWnitive, probable and suspicious FMF groups. Myalgia frequency was reported to be 9, 7.8 and 2.4% in these subgroups, respectively, the diVerence among the groups being not statistically signiWcant. The rate of myalgia in their group was 6.1% in total, while 20.3% of our patients had myalgia [2–4]. Those patients with protracted febrile myalgia presented to our clinic mostly during the spring months, and their ASO levels were high [2, 3]. Most cases with myalgia were homozygous or compound heterozygous for M694V mutation, while only one case was homozygous for E148Q [2, 5]. One of the patients with myalgia had also amyloidosis and osteopoikilosis and he was transplanted for end stage renal disease [6].