A single-nucleotide polymorphism rs708567 in the IL-17RC gene is associated with a susceptibility to and the curve severity of adolescent idiopathic scoliosis in a Chinese Han population: a case-control study

BACKGROUND Although the pathogenesis of adolescent idiopathic scoliosis (AIS) remains controversial, genetic factors are thought to play key roles in the development of AIS. In a recent genome-wide association study, a polymorphism in the interleukin-17 receptor C (IL-17RC) gene was reported to be associated with the susceptibility to AIS, implicating IL-17RC as a novel predisposing gene for AIS. However, as this association has not been replicated in other populations, its global applicability remains unclear. METHODS A total of 529 Chinese girls with AIS and 512 healthy age-matched controls were recruited in this case-control study from June 2007 to December 2009. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect the genotype of the single-nucleotide polymorphism (SNP) rs708567 in the IL-17RC gene. Case-control and case-only studies were performed to determine the association between the IL-17RC gene polymorphism and the susceptibility to and curve severity of AIS. RESULTS The GG genotype and G allele frequencies were significantly higher in the AIS patients than in the controls (χ2 test: P = 0.023 and 0.028, respectively). The risk for the GG genotype is 1.550-fold (95% CI: 1.062 - 2.261) higher than the AG genotype, and the risk for the G allele is 1.507-fold (95% CI: 1.046 - 2.172) higher than the A allele. Additionally, a subgroup of skeletally mature AIS patients (n = 241) who carried the GG genotype showed a significantly higher mean maximum Cobb angle than those carrying the AG genotype (36.01 ± 13.12° vs. 28.92 ± 7.43°, P = 0.007). CONCLUSIONS This study confirms the significant association between the IL-17RC gene polymorphism and the susceptibility to and curve severity of AIS in a Chinese Han population, suggesting that the IL-17RC gene is an AIS-predisposing gene in Chinese Han population.