A Missing Correlation between the Number and Type of MEFV Mutations and Severity of Clinical Manifestations in Egyptian Pediatric FMF Patients

Abstract

Aims: Previous researches identified the gene for Familial Mediterranean Fever (FMF) and found several different gene mutations that cause this inherited rheumatic disease. The aim of this work is to investigate the correlation between severity of symptoms of FMF and the number and type of MEFV variants, as well as to shed light on the correlation between the genotype and phenotype of Egyptian pediatric FMF patients. Study Design: Retrospective study. Place and Duration of Study: Department of Pediatrics, Kasr El Aini Hospital, Cairo University Medical School, Cairo, Egypt, between January 2012 and February 2013. Methodology: This study involved 35 childhood cases of Egyptian ethnic origin suspected to suffer from FMF. They include 19 males and 16 females of age range between 1-17 years. MEFV mutations in each patient were determined by performing DNA isolation and purification, in vitro amplification (PCR), and reverse hybridization using an FMF StripAssay. Results: Our results revealed 14% homozygous, 34% single heterozygous, 35% compound heterozygous-bi, and 17% compound heterozygous-tri patients. Twelve MEFV mutations were covered where all mutations were concentrated on exons 10 and 2. Severity of clinical manifestations and severity score did not linearly correlate with the number of variants, nor with the type of variant. Conclusion: Our results question the strength of genotype-phenotype correlation in FMF and indicate that MEFV genotypes express much more variable phenotypes than previously suggested. Our results also revealed no association between the number of mutations and severity of clinical manifestations.