Quantitation Analysis of PCDH10 Methylation in Adolescent Idiopathic Scoliosis Using Pyrosequencing Study

Study Design. A retrospective and comparative study. Objective. To evaluate the difference of DNA methylation in protocadherin10 (PCDH10) genes between adolescent idiopathic scoliosis (AIS) and normal controls, and to assess the association between DNA methylation and the etiology of AIS. Summary of Background Data. The PCDH10 gene showed abnormal expression in AIS. However, the mechanism was still unclear. DNA methylation was an important epigenetic mechanism at the interface between genetics and environmental phenotype, seeming to be a suitable epigenetic mark for the abnormal expression of PCDH10 in AIS. Methods. There were 50 AIS patients and 50 healthy controls included in the study. The peripheral blood sample of each participant was taken. The pyrosequencing assay was used to assess the methylation status of PCDH10 promoter and real time PCR (RT-PCR) was used to detect the PCDH10 gene expression. The comparison analysis was performed using independent t test and 2-tailed Pearson coefficients was calculated for the correlation analysis. Results. The average methylation level was 4.32 +/- 0.73 in AIS patients and 3.14 +/- 0.97 in healthy controls (P < 0.001). The PCDH10 gene expression was 0.23 +/- 0.04 in AIS patients and 0.36 +/- 0.08 in normal controls (P < 0.0001). Statistically significant linear correlation was found between PCDH10 gene methylation level and Cobb angle of major curve (P < 0.001). Besides, a significant negative correlation between PCDH10 methylation and PCDH10 gene expression was found (P < 0.001). Conclusion. AIS patients were associated with high DNA methylation level and low gene expression of PCDH10 gene rather than normal controls. The high methylation level indicated high Cobb angle of major curves in AIS. The abnormal DNA methylation may widely exist and serve as a potential mechanism for AIS.