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Meeting Reports 2005

FMF and Beyond
The Fourth International Congress on Systemic Autoinflammatory Diseases
(FMF 2005 - Abstracts)

November 6-10, 2005

Abstract Report

Abstract Details for İsmail Sarı
Abstract Information :
Comparison of Phenotypes of Wild-type and other Genotypes of the FMF Patients

Ismail  Sari1, Guldal  Kirkali2, and Mehmet Tunca3            

1Dokuz Eylul University School of Medicine Department of Rheumatology, Izmir Turkey; 2Dokuz Eylul University School of Medicine Department of Biochemistry, Izmir Turkey; 3Dokuz Eylul University School of Medicine Department of Internal Medicine, Izmir Turkey

OBJECTIVE
Despite intensive sequencing, a substantial number of FMF patients display none of the known mutations on the MEFV gene. The aim of this study was to investigate if there was any phenotypic difference between the wild-type and other genotypes.

PATIENTS AND METHODS
We studied the 212 patients who were previously genotyped. Exon 10 was fully sequenced in all cases and the mutation encoding pyrin E148Q was sought by gel electrophoresis of the 5 prime exon 2 amplicon after MvaI digestion. Following data were collected and analyzed: sex, age, disease duration, delay of diagnosis, genotype status, number of attacks per year, presence of fever, abdominal pain, pleuritic pain, arthritis, erysipelas-like erythema (ELE) and inflammatory back pain (IBP).

RESULTS
Among the 212 patients who were genotyped none of the searched mutations were detectable in 23 (10.85%) of them. There was no significant difference between patients with various mutations and wild genotype regarding the above-mentioned demographical and clinical parameters. We then compared this group with M694V homozygotes (n: 34) who are universally accepted as a “severe” phenotype, and M680I homozygous (n: 12) patients whose phenotypic expression is more controversial. Homozygous M694V cases had significantly more pronounced pleuritic pain (78.8 vs 52.2%), arthritis (82.4 vs 26.1%) and ELE (57.6 vs 9.5%) than wild-type FMF patients, while the latter displayed a phenotypic expression in parallel with the M680I homozygotes.

CONCLUSION
Wild type phenotype is essentially similar to patients in general. Since 10-15 percent of FMF patients fit in this category, genotyping for diagnostic purposes will only complicate the clinical decision making process.
 
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