Prevalence and significance of mutations in the familial Mediterranean fever gene in Henoch-Schönlein purpura.

OBJECTIVES: Based on the fact that Henoch-Schönlein purpura (HSP) occurs in approximately 5% of persons with familial Mediterranean fever (FMF), we assessed the prevalence and significance of FMF gene mutations in children with one or more episodes of HSP.

STUDY DESIGN: Thirty-four boys and 18 girls treated for HSP at Rambam Medical Center were interviewed and asked to donate blood. Mean age at disease onset was 6.7+/-2. 4 years, and mean follow-up was 3.8+/-1.3 years. Six predominant mutations (M694V, M680I, M694I, V726A, K695R, E148Q) in the MEFV gene were studied.

RESULTS: Nine heterozygotes, three homozygotes and two compound heterozygotes, were identified. Altogether, five persons (10%) carried two mutated MEFV alleles, a number significantly exceeding that determined for the general Israeli population (1%-2%). Of these, three displayed genotypes associated with a mild form of disease (M694V/E148Q and V726A/V726A), and two had genotypes normally observed in disease-free persons (E148Q/K695R and E148Q/E148Q).

CONCLUSIONS: Occult FMF cases much more numerous than expected were identified among children presenting with HSP. Such children should be closely monitored for renal complications, and treatment with colchicine should be considered.