[No evidence for genetic association between alpha-2 macroglobulin I1000V polymorphism and sporadic Alzheimer's disease in two independent Chinese populations].
ABSTRACT Alpha-2 macroglobulin (alpha2M) is a proteinase inhibitor found in association with senile plaques in Alzheimer's disease (AD). Also alpha2M has been implicated in several pathophysiological processes in AD. In view of the recent contradictory reports on the relationship between AD and a common polymorphism I1000V in A2M gene, the present authors studied a relatively large sample, determined the genotype of the I1000V polymorphism in A2M gene in sporadic AD patients and age-matched controls with normal cognition, and examined the possible association of the polymorphism with AD.
Genotypes of A2M and apolipoprotein E (apoE) were detected by polymerase chain reaction combined with restriction fragment length polymorphism in 257 patients and 242 controls in Guangzhou, and 112 patients and 113 controls in Chengdu.
The 1000Val allele frequencies in the merged AD and control groups were 7.7% and 8.7%, respectively. The differences of allelic and genotypic frequencies between the patients and control subjects were not statistically significant, even after stratification by apoE epsilon4 status or by age-of-onset of the disease.
The results of this study revealed no association between the I1000V polymorphism of A2M and Chinese sporadic AD in Guangzhou and Chengdu.
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ABSTRACT: Accumulating studies have evaluated the association of Alpha-2-Macroglobulin gene (A2M) 5 bp insertion/deletion (5 bp I/D, rs3832852) and Ile1000Val (rs669) polymorphisms with Alzheimer's disease (AD) risk, but the results remain inconclusive. To investigate whether these two polymorphisms facilitate the susceptibility to AD, we conducted a comprehensive systematic review and meta-analysis. Databases of PubMed, Embase, Web of Science, Medline, CNKI, and Google Scholar were searched to get the genetic association studies. All statistical analyses were conducted with Review Manager 5.2 and STATA11.0. Fifty-two articles were included in the final meta-analysis. We performed meta-analysis of 39 studies involving 8,267 cases and 7,932 controls for the 5 bp I/D polymorphism and 27 studies involving 6,585 cases and 6,637 controls for the Ile/Val polymorphism. Overall results did not show significant association between these two polymorphisms and AD risk in dominant, recessive, and multiplicative genetic models. On the stratification analyses by ethnicity and APOE ε4 status with genotypes of polymorphism sites, similar negative associations were found. The meta-analysis suggests that there is no enough evidence for associations of A2M gene polymorphisms (5 bp I/D, Ile1000Val) with AD risk at present, even after stratification by ethnicity and APOE ε4 with genotypes of polymorphism sites. However, due to the heterogeneity in the meta-analysis, the results should be interpreted with caution.Cell biochemistry and biophysics 04/2014; · 3.34 Impact Factor