Analysis of the Effects of SAA1 Gene Polymorphisms on Renal Involvement in a Familial Mediterranean Fever Jordanian Population.

Abstract

Familial Mediterranean Fever (FMF) is an inherited autosomal recessive disorder resulting from the inheritance of MEFV gene mutations. Patients with FMF are at increased risk of secondary amyloidosis, namely type AA. In some Mediterranean populations, the α genotype was associated with the development of renal amyloidosis, a finding not reproduced in other populations. Our study aimed to assess the association of SAA1 genotypes with renal involvement. This is a retrospective analysis of FMF patients which were followed at our institute between January 2016 and August 2022. Familial Mediterranean Fever screening was performed using polymerase chain reaction and reverse hybridization techniques. Statistical analysis was performed using bivariate logistic regression. MEFV analysis of the studied patients (n=427) identified 52 patients with a homozygous genotype (12.1%) and 374 with a heterozygous genotype (87.5%). The heterozygous group were mostly heterozygous carriers of a single FMF variant (81%), while 19% were compound heterozygous. Renal involvement was revealed in 95 patients (22.2%), which were manifested as proteinuria (21.3%) and/or renal impairment in 4 patients (3%). The clinical diagnosis of amyloidosis was suspected in 6 patients only (1.4%). Analysis for SAA1 gene genotype-phenotype correlation showed that patients with the SAA1.1/1.1 (OR=0.54, P=.452) was not statistically associated with renal involvement. Pearson Chi-square was performed to examine the association between FMF homozygosity and each SAA1 genotype, which showed a significant association between FMF gene homozygosity with SAA1.1/1.1 genotype (χ2 = 8.06, P=.018). In our Jordanian FMF population, we report low rates of renal involvement with a high rate of the β haplotype (SAA1.5). Neither the α/α nor the β/β genotypes were associated with evidence of renal involvement.