Senile systemic amyloidosis affects 25% of the very aged and associates with genetic variation in alpha2-macroglobulin and tau: a population-based autopsy study.
BACKGROUND
Senile systemic amyloidosis (SSA) is characterized by deposition of wild-type transthyretin (TTR)-based amyloid in parenchymal organs in elderly individuals. Previously, no population-based studies have been performed on SSA.


METHODS
Here we have studied the prevalence and risk factors for SSA in a Finnish autopsied population aged 85 or over, as part of the population-based Vantaa 85+ Autopsy Study (n = 256). The diagnosis of SSA was based on histological examination of myocardial samples stained with Congo red and anti-TTR immunohistochemistry. The genotype frequencies of 20 polymorphisms in 9 genes in subjects with and without SSA were compared.


RESULTS
The prevalence of SSA was 25%. SSA was associated with age, myocardial infarctions, the G/G (Val/Val) genotype of the exon 24 polymorphism in the alpha2-macroglobulin (alpha2M), and the H2 haplotype of the tau gene (P-values 0.002, 0.004, 0.042, and 0.016).


CONCLUSIONS
This population-based study shows that SSA is very common in old individuals, affecting one-quarter of people aged over 85 years. Myocardial infarctions and variation in the genes for alpha2M and tau may be associated with SSA.
Tanskanen
Maarit
M
Department of Pathology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland. maarit.tanskanen@helsinki.fi
Peuralinna
Terhi
T
Polvikoski
Tuomo
T
Notkola
Irma-Leena
IL
Sulkava
Raimo
R
Hardy
John
J
Singleton
Andrew
A
Kiuru-Enari
Sari
S
Paetau
Anders
A
Tienari
Pentti J
PJ
Myllykangas
Liisa
L
D000367:Age Factors; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000453:epidemiology* / Q000235:genetics; D001344:Autopsy; D003224:Congo Red; D005091:Exons; D005260:Female; D005387:Finland / Q000453:epidemiology; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009203:Myocardial Infarction / Q000150:complications; D009206:Myocardium / Q000473:pathology; D011110:Polymorphism, Genetic; D011228:Prealbumin / Q000378:metabolism; D015995:Prevalence; D012307:Risk Factors; D000511:alpha-Macroglobulins / Q000235:genetics*; D016875:tau Proteins / Q000235:genetics*
C054369:MAPT protein, human; D011228:Prealbumin; D000511:alpha-Macroglobulins; D016875:tau Proteins; D003224:Congo Red