Objectives : To investigate LBX1 mRNA expression in bilateral paravertebral muscles in adolescent idiopathic scoliosis (AIS) and control subjects to clarify its association with development and progression of scoliosis. Summary of background data : Paravertebral muscle abnormalities in AIS patients have been investigated through various methods. Despite the roles of LBX1 in skeletal muscles, the association with idiopathic scoliosis is still unclear. Methods : Fourteen AIS patients (average age, 15.9±2.2 years ; average Cobb angle, 48.2±8.9°) and 7 controls (average age, 26.4±9.7 years) were included. Muscle samples were harvested from bilateral paravertebral muscles at the apical vertebral level. LBX1 mRNA expression was evaluated by the real-time PCR. LBX1 expressions in bilateral paravertebral muscles were compared in each group. The expression ratio, the expression at the convex side relative to the concave side, was compared between groups. Correlation between expression ratio and Cobb angle was analyzed. Results : LBX1 expression on the convex side was higher than that on the concave side in AIS group (p=0.020), and the expression ratio of LBX1 in the AIS group was higher than that of controls (p=0.012). However, there was no significant correlation between the expression ratio of LBX1 and Cobb angle (r=－0.3826, p=0.177). Conclusions : In the AIS group, LBX1 mRNA expression was asymmetric. The AIS group had higher expression ratios than the controls. These findings suggest the possible functional role of paravertebral muscles in the development or progression of the spinal curve
