Analysis of SAA1 gene polymorphisms in the Greek population: rheumatoid arthritis and FMF patients relative to normal controls. Homogeneous distribution and low incidence of AA amyloidosis.
OBJECTIVE
To address whether or not the rarity of amyloidosis in Greek patients with rheumatoid arthritis (RA) is related to specific alleles of single nucleotide polymorphisms (SNPs) in the 5'-flanking region and the exon 3 of the SSA1 gene.


METHODS
The genotypes of the -13T/C SNP in the 5'-flanking region of the SAA1 gene and the two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined in 88 Greek patients with RA, 14 patients with familial Mediterranean fever (FMF) and 110 healthy controls. Linkage disequilibrium and haplotype frequencies involving -13T/C, 2995C/T and 3010C/T in these populations were tested and estimated, respectively.


RESULTS
The genotypic distribution and allelic frequencies were similar in all groups tested. SNPs 2995 and 3010 were in linkage disequilibrium for all study populations (p < 0.05), whereas SNP -13 was not in linkage disequilibrium with either 2995 or 3010 (p > or = 0.05). Two major haplotypes presented in all patients with RA and FMF and controls: -13C; 2995T; 3010C (-13C; alpha) and -13C; 2995C; 3010T (-13C; beta). The -13T allele was linked with the gamma haplotype in Greek patients with RA and controls. The frequency of the -13T allele was found to be very rare in all groups tested.


CONCLUSIONS
In conclusion, the rarity of the putative amyloidogenic -13T allele in Greek populations may be related to low prevalence of AA amyloidosis development in Greek RA patients.
Mavragani
Clio P
CP
Department of Pathophysiology, National University of Athens School of Medicine, Greece.
Yiannakouris
Nikos
N
Zintzaras
Elias
E
Melistas
Labros
L
Ritis
Kostas
K
Skopouli
Fotini N
FN
D000328:Adult; D000368:Aged; D000686:Amyloidosis / Q000097:blood / Q000235:genetics*; D001172:Arthritis, Rheumatoid / Q000208:ethnology / Q000235:genetics*; D005091:Exons / Q000235:genetics; D010505:Familial Mediterranean Fever / Q000208:ethnology / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D006115:Greece; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D015810:Linkage Disequilibrium; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D000685:Serum Amyloid A Protein / Q000032:analysis / Q000235:genetics*; D044465:White People / Q000235:genetics
C521404:SAA1 protein, human; D000685:Serum Amyloid A Protein