Amyloidosis in familial Mediterranean fever patients: correlation with MEFV genotype and SAA1 and MICA polymorphisms effects.
BACKGROUND
Familial mediterranean fever (FMF) is a recessively inherited disease characterized by recurrent crises of fever, abdominal, articular and/or thoracic pain. The most severe complication is the development of renal amyloidosis. Over 35 mutations have been discovered so far in the gene responsible for the disease, MEFV. This article aims at determining a correlation between the MEFV genotype and the occurrence of amyloidosis in FMF patients, in addition to the study of the modifying effects of the SAA1 (type 1 serum amyloid A protein) and MICA (Major Histocompatibility Complex (MHC) class-I-chain-related gene A) genes on this severe complication.


METHODS
Fourteen MEFV mutations were screened and the SAA1 and MICA polymorphisms tested in 30 FMF patients with amyloidosis and 40 FMF patients without amyloidosis.


RESULTS
The M694V and V726A allelic frequencies were, respectively, significantly higher and lower in the group with amyloidosis, compared to the control FMF group. The beta and gamma SAA1 alleles were more frequently encountered in the group without amyloidosis, whereas the alpha allele was significantly more observed in FMF patients with amyloidosis (p < 0.025). All the MICA alleles were encountered in both patients' groups, but none of them was significantly associated with amyloidosis.


CONCLUSIONS
The results suggest a protective effect of the SAA1 beta and gamma alleles on the development of amyloidosis and show the absence of a MICA modifying effect on amyloidosis development. Testing these polymorphisms on a larger sample will lead to more definite conclusions.
Medlej-Hashim
Myrna
M
Unité de Génétique Médicale, Faculté de Médecine, Université Saint Joseph, Beirut, Lebanon. myrnahachem@hotmail.com
Delague
Valérie
V
Chouery
Eliane
E
Salem
Nabiha
N
Rawashdeh
Mohammed
M
Lefranc
Gérard
G
Loiselet
Jacques
J
Mégarbané
André
A
D000293:Adolescent; D000328:Adult; D000483:Alleles; D000686:Amyloidosis / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D003598:Cytoskeletal Proteins; D010505:Familial Mediterranean Fever / Q000150:complications / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D011110:Polymorphism, Genetic; D011506:Proteins / Q000235:genetics*; D000071198:Pyrin; D000685:Serum Amyloid A Protein / Q000235:genetics*
D003598:Cytoskeletal Proteins; D015395:Histocompatibility Antigens Class I; C000604192:MEFV protein, human; C099187:MHC class I-related chain A; D011506:Proteins; D000071198:Pyrin; D000685:Serum Amyloid A Protein