Single nucleotide polymorphism rs708567 in IL-17RC gene is associated with a susceptibility to and 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 a key role 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 susceptibility to AIS, implicating IL-17RC as a novel predisposition gene for AIS. However, as this association has not been replicated in other populations, its global applicability is unclear. Methods. A total of 529 Chinese girls with AIS and 512 healthy, age-matched controls were recruited from June 2007 to December 2009. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was carried out to detect the genotype of single nucleotide polymorphism (SNP) rs708567 in the IL-17RC gene. Case-control and case-only studies were performed to determine the associations between the IL-17RC gene polymorphism and the susceptibility to and the curve severity of AIS. Results. The GG genotype and G allele frequency were significantly higher in the AIS patients than that in the controls (χ2 test: P = 0.023 and 0.028, respectively). Both the GG genotype and G allele significantly increased the risk of AIS by an OR of 1.550 (95% CI: 1.062 2.261) and 1.507 (95% CI: 1.046 2.172), respectively. In addition, in a subgroup of skeletally mature AIS patients (n=241), who carrying GG genotype showed a significantly higher mean maximum Cobb angle than those carrying AG genotype (36.93 ± 13.15° vs. 28.52 ± 7.76°, P = 0.004). Conclusion. This study confirms a significant association between the IL-17RC gene polymorphism and the susceptibility to and the curve severity of AIS in a Chinese Han population, suggesting that the IL-17RC gene is not only an AIS predisposition gene but is also a disease-modifying gene in the Chinese Han population.