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Predicting genetic risk factors for AA amyloidosis in Algerian patients with familial Mediterranean fever

Premier auteur : Djouher Ait-Idir


Revue :  Molecular Genetics and Genomics


Amyloid-associated renal amyloidosis (AA) is a severe complication of familial Mediterranean fever (FMF). Its occurrence has been reported to be associated with polymorphisms in the serum amyloid A1 (SAA1) gene and variants in the MEFV gene, associated with FMF respectively.

In Algeria, the association between SAA1 variants and FMF-related amyloidosis had not been studied, hence the aim of this case-control study.


120 subjects were included including 60 healthy controls and 60 unrelated FMF patients (39 with amyloidosis and 21 without). All were genotyped for SAA1 alleles (SAA1.1, SAA1.5 and SAA1.3), and a subset for the 13 C/T polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Comparisons between genotype and allele frequencies were made using the chi-square and Fisher tests.


Among the 39 FMF patients with AA amyloidosis, there were 18 males for 21 females; mean age was 39.5 years with a mean age at onset of FMF of 11.5 years and a mean number of FMF progression years of 24.5 years; In 36% of cases there was consanguinity and a family history. 77% were treated with colchicine. There was no significant difference for these elements compared with FMF patients without amyloidosis.


The SAA1.1/1.1 genotype was predominant in patients with FMF complicated with AA amyloidosis compared with patients with FMF without amyloidosis (p = 0.001) and controls (p < 0.0001).

The SAA1.1/1.5 genotype was higher in patients without amyloidosis (p = 0.0069) and controls (p = 0.0082) than in patients with amyloidosis.

Bivariate logistic regression revealed an increased risk of AA amyloidosis with three genotypes, SAA1.1/1.1 [odds ratio 7.589 (OR); 95% confidence interval (CI): 2.130-27.041] (p = 0.0018), SAA1. 1/1.3 [OR 5.700; 95% CI: 1.435-22.644] (p = 0.0134), and M694I/M694I [OR 4.6; 95% CI: 1.400-15.117] (p = 0.0119).

The SAA1.1/1.5 - 13 C/C genotype group [OR 0.152; 95% CI: 0.040-0.587] (p = 0.0062) was protective against amyloidosis.

In all groups, the -13 C/C genotype predominated and was not associated with renal complications [OR 0.88; 95% CI: 0.07-10.43] (p = 0.915).

Discussion and conclusion:

In conclusion, unlike the -13 C/T polymorphism, the SAA1.1/1.1, SAA1.1/1.3 and M694I/M694I genotypes may increase the risk of developing renal AA amyloidosis in the Algerian population with familial Mediterranean fever.

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