Mutations in the gene for familial Mediterranean fever: do they predispose to inflammation?
OBJECTIVE
To analyze 70 individuals who were found to have the Mediterranean fever (MEFV) gene for the presence of definite familial Mediterranean fever (FMF) and to assess if they were prone to clinical and laboratory inflammation. We also prospectively evaluated 72 patients with childhood rheumatic diseases for the presence of MEFV mutations.


METHODS
Seventy patients with one MEFV gene mutation were reevaluated for the presence of a clinical FMF phenotype using a new set of criteria. They were also questioned for the presence of musculoskeletal symptoms and rheumatic diseases. They were sampled for erythrocyte sedimentation rates and C-reactive protein levels. A second group with childhood rheumatic diseases were diagnosed according to international criteria.


RESULTS
Median age of the 70 heterozygous individuals was 12 years. About 1/3 (34.3%) were classified with clinical FMF phenotype according to the suggested criteria. Fifteen (21.4%) were classified as normal and 3 (4.3%) had recurrent abdominal pains but did not fulfill all criteria for clinical FMF. Overall, 28 (40.0%) had some form of rheumatic complaint and 15 (21.4%) had developed a rheumatic disease including Behçet's disease, a vasculitis, or acute rheumatic fever. The mean ESR and CRP levels were 45.47 +/- 33.05 mm/h and 4.00 +/- 6.73 mg/dl, respectively. Among the 72 patients with rheumatic diseases of childhood, 22 (30.5%) carried one or 2 mutations of the MEFV gene. The mutated allele frequency among patients with rheumatic diseases was significantly higher than those in controls (p < 0.05). Within this group, among the 59 patients with juvenile idiopathic arthritis 15 had mutations in the heterozygous or homozygous form.


CONCLUSIONS
We confirm the acute phase response in the carriers for MEFV mutations. We suggest that these patients may have a tendency to develop certain manifestations due to an increased baseline of inflammation, and the presence of these mutations may affect their disease course when they develop rheumatic disease.
Ozen
Seza
S
Department of Pediatrics, Hacettepe University, 06100 Ankara, Turkey. sezaozen@hacettepe.edu.tr
Bakkaloglu
Aysin
A
Yilmaz
Engin
E
Duzova
Ali
A
Balci
Banu
B
Topaloglu
Rezan
R
Besbas
Nesrin
N
D000293:Adolescent; D001171:Arthritis, Juvenile / Q000235:genetics* / Q000503:physiopathology; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003598:Cytoskeletal Proteins; D004252:DNA Mutational Analysis; D010505:Familial Mediterranean Fever / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000503:physiopathology; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011336:Probability; D011446:Prospective Studies; D011506:Proteins / Q000235:genetics*; D000071198:Pyrin; D018570:Risk Assessment; D012720:Severity of Illness Index
D003598:Cytoskeletal Proteins; C000604192:MEFV protein, human; D011506:Proteins; D000071198:Pyrin