Risk factors for AA amyloidosis in Germany.
OBJECTIVE
To identify risk factors for serum amyloid-A (AA) amyloidosis in patients living in Germany.


METHODS
Clinical and genetic data were obtained from 71 patients with AA amyloidosis. SAA1 genotypes were analyzed in 231 individuals. Control groups comprised 45 patients with long-standing inflammatory diseases without AA amyloidosis and 56 age-matched patients without any inflammatory disease.


RESULTS
The most frequent underlying diseases of AA amyloidosis were familial Mediterranean fever (FMF) (n = 24, 34%) and inflammatory rheumatic diseases (n = 30, 42%). Patients without any known underlying disease (n = 11, 16%) were considered as having idiopathic AA amyloidosis. Patients with FMF were significantly younger at disease onset and younger at diagnosis of AA amyloidosis compared with patients with rheumatic diseases. Patients with idiopathic AA amyloidosis were older than patients with definite rheumatic diseases. Patients with FMF and high penetrance MEFV gene mutations had a relative risk of 1.73 for AA amyloidosis. Patients with FMF or a rheumatic disease and the SAA1 α/α genotype had a relative risk of 4.86 and 2.53, respectively, for developing an AA amyloidosis. The prevalence of this risk genotype was 36% in German patients without an inflammatory disease, 92% in German patients with AA amyloidosis and 100% in German patients with idiopathic AA amyloidosis.


CONCLUSIONS
Risk factors for AA amyloidosis are the presence of a hereditary autoinflammatory or chronic rheumatic disease, elevated C-reactive protein and SAA serum levels, a long delay of a sufficient therapy, an advanced age and the SAA1α/α genotype.
Department of Medicine V, Amyloidosis Center and Division of Rheumatology, University of Heidelberg , Heidelberg , Germany .
Norbert
N
Blank
Ute
U
Hegenbart
Peter
P
Lohse
Jörg
J
Beimler
Christoph
C
Röcken
Anthony D
AD
Ho
Hanns-Martin
HM
Lorenz
Stefan O
SO
Schönland
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000686:Amyloidosis / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D005858:Germany / Q000453:epidemiology; D006801:Humans; D000075363:Immunoglobulin Light-chain Amyloidosis; D008875:Middle Aged; D012307:Risk Factors; D000685:Serum Amyloid A Protein / Q000235:genetics*; D055815:Young Adult
C521404:SAA1 protein, human; D000685:Serum Amyloid A Protein
Amyloidosis; SAA1 genotype; familial Mediterranean fever; rheumatoid arthritis; serum amyloid-A protein