Lack of association between the promoter polymorphisms of MMP-3 and IL-6 genes and adolescent idiopathic scoliosis: a case-control study in a Chinese Han population.
METHODS
Case-control study.


OBJECTIVE
This study is to replicate the association between the promoter polymorphisms of matrix metalloproteinase (MMP)-3 (-1171 5A/6A rs3025058) and interleukin (IL)-6 genes (-174G/C rs1800795) and adolescent idiopathic scoliosis (AIS) in a Chinese Han population.


BACKGROUND
Recently, promoter polymorphisms in MMP-3 and IL-6 have been reported to be associated with AIS. Such genetic association, if confirmed by replication in other samples, would point to a primary degenerative defect in the disc or nucleus pulposus and inflammation as the key pathogenic mechanisms of AIS.


METHODS
A total of 487 Chinese girls with AIS and 494 healthy age-matched adolescent girls were recruited consecutively during a 3-year period. The same genotyping technique as the original report was used to detect promoter polymorphisms of the MMP-3 and IL-6 genes. Statistical analysis of genotype frequencies between AIS patients and normal controls were performed by chi test.


RESULTS
In this association study of the MMP-3 polymorphism and the risk of scoliosis, no significant difference was found between cases and controls, both in term of allelic association (6A: 81.2% in cases vs. 81.8% in controls, 5A: 18.8% in cases vs. 18.2% in controls, P = 0.745) or genotype association (6A/6A: 65.9% in cases vs. 66.2% in controls, 5A/6A: 30.6% in cases vs. 31.2% in controls, and 5A/5A: 3.5% in cases vs. 2.6% in controls; P = 0.733). Among AIS patients, the maximal Cobb angles were also not different among MMP-3 genotypes (6A/6A: 31.1 degrees +/- 9.7 degrees, 5A/6A: 29.1 degrees +/- 10.5 degrees, and 5A/5A: 29.4 degrees +/- 11.2 degrees; P = 0.392). As for IL-6 polymorphism, -174G/C polymorphism was not found in the Chinese AIS patients, and all 100 AIS patients and 100 normal controls were found to carry the G/G wild type.


CONCLUSIONS
This study did not find any significant association of promoter polymorphisms of the MMP-3 (-1171 5A/6A rs3025058) and IL-6 gene (-174G/C rs1800795) with AIS. The results indicate that the MMP-3 promoter polymorphism is not associated with AIS in the Chinese population. Further studies, however, are needed to rule out the potential association with other promoter polymorphisms in IL-6.
Liu
Zhen
Z
Spine Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China.
Tang
Nelson L S
NL
Cao
Xing-Bin
XB
Liu
Wen-Jun
WJ
Qiu
Xu-Sheng
XS
Cheng
Jack C Y
JC
Qiu
Yong
Y
D000293:Adolescent; D044466:Asian People / Q000235:genetics; D016022:Case-Control Studies; D002648:Child; D002681:China / Q000208:ethnology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000208:ethnology / Q000235:genetics*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D019278:Matrix Metalloproteinase 3 / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012600:Scoliosis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
D015850:Interleukin-6; D019278:Matrix Metalloproteinase 3