Interleukin-6 receptor gene polymorphisms and periodontitis in a non-smoking Japanese population.
OBJECTIVE
The indispensable role of interleukin-6 receptor (IL-6R) in regulating IL-6 responses has been clearly established. We have previously reported that IL6R polymorphisms strongly influenced the serum levels of soluble IL-6R. In this study, we investigated the association between these genetic variations and periodontitis.


METHODS
Among the seven novel IL6R single-nucleotide polymorphisms (SNPs) reported, we genotyped two important sites: the +48892 A/C in exon 9 and the -183 G/A in the promoter region. The SNP in exon 9 results in Asp-->Ala substitution in the proteolytic cleavage site of IL-6Ralpha. In total, 212 periodontitis cases and 210 healthy controls were genotyped using polymerase chain reaction, restriction fragment length polymorphisms and direct sequencing methods.


RESULTS
Analysis of the genotype distribution of the +48892 A/C SNP in periodontitis patients and in controls revealed a suggestive association with aggressive (p = 0.04) and chronic periodontitis (p = 0.04). In addition, the carriage rate for the A allele was significantly higher in chronic periodontitis patients [p = 0.02, odds ratio (OR) = 2.25]. No association was found in the -183 G/A SNP. The two markers were in linkage disequilibrium (LD) (|D'| = 0.53).


CONCLUSIONS
The IL6R+48892 A/C polymorphism could act as a risk factor for periodontitis; however, further association and biological studies are needed.
Galicia
Johnah C
JC
Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Tai
Hideaki
H
Komatsu
Yasutaka
Y
Shimada
Yasuko
Y
Ikezawa
Ikuyo
I
Yoshie
Hiromasa
H
D000225:Adenine; D000328:Adult; D000368:Aged; D000409:Alanine / Q000235:genetics; D000483:Alleles; D001224:Aspartic Acid / Q000235:genetics; D015415:Biomarkers / Q000032:analysis; D003596:Cytosine; D005091:Exons / Q000235:genetics; D005260:Female; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006801:Humans; D007564:Japan; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000235:genetics / Q000276:immunology*; D011110:Polymorphism, Genetic / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D019947:Receptors, Interleukin-6 / Q000235:genetics*
D015415:Biomarkers; D019947:Receptors, Interleukin-6; D001224:Aspartic Acid; D003596:Cytosine; D000225:Adenine; D000409:Alanine