BACKGROUND: VDR may be considered as a candidate gene potentially related to 
idiopathic scoliosis susceptibility and natural history. Transcriptional profile 
of VDR mRNA isoforms might be changed in the structural tissues of the scoliotic 
spine and potentially influence the expression of VDR responsive genes. The 
purpose of the study was to determine differences in mRNA abundance of VDR 
isoforms in bone, cartilage and paravertebral muscles between tissues from curve 
concavity and convexity, between JIS and AIS and to identify VDR responsive 
genes differentiating juvenile and adolescent idiopathic scoliosis in 
paravertebral muscles.
METHODS: In a group of 29 patients with JIS and AIS, specimens of bone, 
cartilage, paravertebral muscles were harvested at the both sides of the curve 
apex together with peripheral blood samples. Extracted total RNA served as a 
matrix for VDRs and VDRl mRNA quantification by QRT PCR. Subsequent microarray 
analysis of paravertebral muscular tissue samples was performed with HG U133A 
chips (Affymetrix). Quantitative data were compared by a nonparametric Mann 
Whitney U test. Microarray results were analyzed with GeneSpring 11GX 
application. Matrix plot of normalized log-intensities visualized the degree of 
differentiation between muscular tissue transcriptomes of JIS and AIS group. 
Fold Change Analysis with cutoff of Fold Change ≥2 identified differentially 
expressed VDR responsive genes in paravertebral muscles of JIS and AIS.
RESULTS: No significant differences in transcript abundance of VDR isoforms 
between tissues of the curve concavity and convexity were found. Statistically 
significant difference between JIS and AIS group in mRNA abundance of VDRl 
isoform was found in paravertebral muscles of curve concavity. Higher degree of 
muscular transcriptome differentiation between curve concavity and convexity was 
visualized in JIS group. In paravertebral muscles Tob2 and MED13 were selected 
as genes differentially expressed in JIS and AIS group.
CONCLUSIONS: In Idiopathic Scolioses transcriptional activity and alternative 
splicing of VDR mRNA in osseous, cartilaginous, and paravertebral muscular 
tissues are tissue specific and equal on both sides of the curve. The number of 
mRNA copies of VDRl izoform in concave paravertebral muscles might be one of the 
factors differentiating JIS and AIS. In paravertebral muscles Tob2 and Med13 
genes differentiate Adolescent and Juvenile type of Idiopathic Scoliosis.