Interleukin 6-174 G/C promoter and variable number of tandem repeats (VNTR) gene polymorphisms in sporadic Alzheimer's disease.
BACKGROUND
Previous studies examining the association between the interleukin 6 (IL-6)-174 C/G polymorphism and Alzheimer's disease (AD) have yielded conflicting results. Furthermore, the C allele of the IL-6 variable number of tandem repeats (VNTR) polymorphism was associated with a delayed onset and a decreased risk of AD.


METHODS
A total sample of 149 AD patients, and 298 age- and sex-matched unrelated caregivers from Apulia, southern Italy, were genotyped for the apolipoprotein E (APOE) polymorphism, the VNTR polymorphism in the 3' flanking region, and the -174G/C single-nucleotide polymorphism (SNP) in the promoter region of IL-6 gene on chromosome 7. Furthermore, we performed a haplotype analysis on these two polymorphisms on IL-6 locus.


RESULTS
IL-6 VNTR and -174G/C allele and genotype frequencies were similar between AD patients and controls, also after stratification for late-onset (> or =65 years) and early-onset (<65 years) or APOE epsilon4 status. Furthermore, there was no evidence of linkage disequilibrium between the VNTR and -174G/C polymorphisms, not supporting a previous reported additive effect of both IL-6 polymorphisms on AD risk.


CONCLUSIONS
Our findings did not support a role of IL-6-174 G/C and IL-6 VNTR polymorphisms in the risk of sporadic AD in southern Italy, suggesting that these polymorphisms of IL-6 gene were at most weak genetic determinants of AD.
Capurso
Cristiano
C
Department of Geriatrics, University of Foggia, Ospedali Riuniti, Viale L. Pinto, 71100 Foggia, Italy. c.capurso@unifg.it
Solfrizzi
Vincenzo
V
Colacicco
Anna Maria
AM
D'Introno
Alessia
A
Frisardi
Vincenza
V
Imbimbo
Bruno P
BP
Lorusso
Maria
M
Vendemiale
Gianluigi
G
Denitto
Marta
M
Santamato
Andrea
A
Seripa
Davide
D
Pilotto
Alberto
A
Fiore
Pietro
P
Capurso
Antonio
A
Panza
Francesco
F
D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D007558:Italy / Q000453:epidemiology; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*
D001057:Apolipoproteins E; D015850:Interleukin-6