Performance of the new Eurofever/PRINTO classification criteria in Familial Mediterranean fever patients with a single exon 10 mutation in childhood

The diagnosis of Familial Mediterranean fever (FMF) based on clinical findings supported by genetic mutation. Recently, the new Eurofever/PRINTO classification criteria including genetic analysis were established. The aim of this study is to evaluate the performance of the new criteria in FMF patients with a single exon 10 mutation in childhood. The study group consisted of FMF patients who had a single exon 10 mutation in a referral center in Turkey. Patients with periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome were included as a control group. The medical charts of all patients were reviewed retrospectively. A total of 106 FMF patients (59 boys) were enrolled in the study group. The median age at first symptom was 5; the median age at diagnosis was 7 years. The mean follow-up was 33 ± 35.4 months. Majority of the patients (n = 58, 54.7%) had heterozygous M694V, 16 (15%) patients had M694V/E148Q and 13 (13.8%) patients had heterozygous M680I mutation. The sensitivity of the Yalcinkaya-Ozen criteria was 98.1% and it was 97.1% for the Eurofever/PRINTO classification criteria. The specificity of the new Eurofever/PRINTO classification criteria was 96.7% and it was 74.1% for the Yalcinkaya-Ozen criteria. The new Eurofever/PRINTO classification criteria have a good sensitivity as the Yalcinkaya-Ozen criteria in patients with a single exon 10 mutation. Additionaly, the new criteria have better specificity. It should be useful to apply the clinical only criteria where the carrier rate is high.