Long-term follow-up of paediatric MEFV carriers

Although familial Mediterranean fever (FMF) is inherited autosomal recessively, some heterozygotes may express disease phenotype and require therapy. To date, there is no study in the literature about how to follow-up Mediterranean fever (MEFV) heterozygotes who do not fulfil FMF criteria in the paediatric age group. This study aims to share a single-centre experience of the long-term clinical and laboratory follow-up of paediatric MEFV carriers. We reviewed the charts of 69 children who were heterozygous for MEFV variants. All children were followed-up with their routine analysis and serum amyloid A levels every 6 months. Thirty-nine children had pathogenic mutations and 30 children had variants of unknown significance. The mean follow-up was 3.2 ± 1.6 years (min 2 years, max 6 years). The children with pathogenic mutations had significantly higher mean SAA levels than the children with variants of unknown significance (p = 0.018); however, the mean CRP and ESR were similar. Besides, the children with pathogenic mutations complained of fever episodes significantly more than the children with variants of unknown significance (p = 0.04). None of the children had persistent proteinuria in the follow-up. We started colchicine in only two patients who were M694V heterozygous. Both patients had family history for FMF and fulfilled the disease criteria after 2 years of follow-up. Neither of these patients had persistently elevated acute phase reactants in their routine follow-up. This study suggested that routine clinical follow-up is useful; however, routine periodic laboratory workup is not necessary among MEFV carriers.