Volume 48, Issue 4 pp. 1149-1155
Research Article

The contribution of genotypes at the MEFV and SAA1 loci to amyloidosis and disease severity in patients with familial Mediterranean fever

Ruth Gershoni-Baruch

Corresponding Author

Ruth Gershoni-Baruch

Rambam Medical Center, and Technion-Israel Institute of Technology, Haifa, Israel

Department of Medical Genetics, Rambam Medical Center, Haifa 31096, IsraelSearch for more papers by this author
Riva Brik

Riva Brik

Rambam Medical Center, and Technion-Israel Institute of Technology, Haifa, Israel

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Nurit Zacks

Nurit Zacks

Sheba Medical Center, Tel-Hashomer, Israel

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Maruan Shinawi

Maruan Shinawi

Rambam Medical Center, Haifa, Israel

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Merav Lidar

Merav Lidar

Sheba Medical Center, Tel-Hashomer, Israel

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Avi Livneh

Avi Livneh

Sheba Medical Center, Tel-Hashomer, and Tel-Aviv University, Tel-Aviv, Israel

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First published: 03 April 2003
Citations: 144

Abstract

Objective

The clinical profile in familial Mediterranean fever (FMF), including its major manifestation, amyloidosis, is influenced by MEFV allelic heterogeneity and other genetic and/or environmental factors. In this study, we analyzed the contribution of genotypes at the MEFV and SAA1 loci to disease severity and to the development of amyloidosis, and further defined the factors affecting the clinical profile of FMF.

Methods

We investigated a sample of 277 FMF patients (154 men and 123 women), including 62 patients with nephropathic amyloidosis, in whom both FMF alleles had been identified. A detailed chart review, interview, and physical examination were undertaken to determine the patients' demographic characteristics, medical history, clinical manifestations, and treatment. The disease severity score was calculated from the Tel-Hashomer key. Genotypes at the SAA1 locus (isoforms α, β, and γ) were determined in all patients. The SAA1 13C/T polymorphism of the SAA1 promotor was analyzed in a subset of cases.

Results

The male:female ratio (154:123, or 1.3) was higher among patients with amyloidosis (40:22, or 1.8) compared with patients without amyloidosis (114:101, or 1.1). Logistic regression analysis showed that homozygosity for the M694V allele (odds ratio [OR] 4.27, 95% confidence interval [95% CI] 2.01–9.07), the presence of the SAAα/α genotype (OR 2.99, 95% CI 1.47–6.09), the occurrence of arthritis attacks (OR 2.43, 95% CI 1.17–5.06), and male sex (OR 1.73, 95% CI 0.90–3.33) were significantly and independently associated with renal amyloidosis. Disease severity was mainly influenced by MEFV mutations and was not associated with genotypes at the SAA1 locus. The SAA1 13T allele was rare, being associated mainly with the SAA γ isoform, and not related to renal amyloidosis.

Conclusion

Overall, disease severity and the development of amyloidosis in FMF are differentially affected by genetic variations within and outside the MEFV gene.

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