Association between Common Variants near <em>LBX1</em> and Adolescent Idiopathic Scoliosis Replicated in the Chinese Han Population

<div><h3>Background</h3><p>Adolescent idiopathic scoliosis (AIS) is one of the most common spinal deformities found in adolescent populations. Recently, a genome-wide association study (GWAS) in a Japanese population indicated that three single nucleotide polymorphisms (SNPs), rs11190870, rs625039 and rs11598564, all located near the <em>LBX1</em> gene, may be associated with AIS susceptibility <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053234#pone.0053234-Takahashi1">[1]</a>. This study suggests a novel AIS predisposition candidate gene and supports the hypothesis that somatosensory functional disorders could contribute to the pathogenesis of AIS. These findings warrant replication in other populations.</p> <h3>Methodology/Principal Findings</h3><p>First, we conducted a case-control study consisting of 953 Chinese Han individuals from southern China (513 patients and 440 healthy controls), and the three SNPs were all found to be associated with AIS predisposition. The ORs were observed as 1.49 (95% CI 1.23–1.80, <em>P</em> = 5.09E-5), 1.70 (95% CI 1.42–2.04, <em>P</em> = 1.17E-8) and 1.52 (95% CI 1.27–1.83, <em>P</em> = 5.54E-6) for rs625039, rs11190870 and rs11598564, respectively. Second, a case-only study including a subgroup of AIS patients (N = 234) was performed to determine the effects of these variants on the severity of the condition. However, we did not find any association between these variants and the severity of curvature.</p> <h3>Conclusion</h3><p>This study shows that the genetic variants near the <em>LBX1</em> gene are associated with AIS susceptibility in Chinese Han population. It successfully replicates the results of the GWAS, which was performed in a Japanese population.</p> </div

Gene expression levels in response to different doses of leptin.

<p>The expression levels in control group without leptin treatment were used as calibrators. Relative expression levels were calculated by using the 2^−ΔΔCt method.</p

Linkage disequilibrium (LD) pattern and Haplotypes of the <i>Leptin</i> gene from the 45 healthy subjects.

<p>Two LD blocks were identified in the sequenced genomic region of the gene (calculated with the Solid spine of LD algorithm with the Minor Allele Frequency≥1%). Arrows indicate the positions of the 6 tag SNPs selected for the association study.</p

6 tag SNPs selected for the association study.

<p>6 tag SNPs selected for the association study.</p

<i>P</i> values of ANOVA for factorial designed data in Adipogenesis assay.

*<p><i>P</i><0.05 was considered statistically significant.</p>**<p><i>P</i><0.01.</p

Results of the Case-control association studies.

a<p>The three values in the “genotype” column indicate the numbers of homozygotes(major allele)/heterozygotes/homozygotes(minor allele) in each SNP, respectively.</p>b<p>After adjusting for age, gender and BMI by logistic regression.</p>c<p>Calculated for the alleles.</p><p>Bonferroni adjustment (All SNPs <i>P</i>_adjusted = 1).</p

Gene expression levels in response to different doses of leptin.

<p>The expression levels in control group without leptin treatment were used as calibrators. Relative expression levels were calculated by using the 2^−ΔΔCt method.</p

Summary of the AIS and control subjects in cytological study.

*<p><i>P</i><0.05 was considered statistically significant.</p>**<p><i>P</i><0.01.</p

Summary of the AIS and control subjects in genetic association study.

*<p><i>P</i><0.05 was considered statistically significant.</p>**<p><i>P</i><0.01.</p

Association between the SNPs near <i>LBX1</i> and AIS predisposition in Chinese Han population.

a<p>Risk alleles were indicated in boldface.</p>b<p>Risk allele frequency (RAF).</p>c<p>Allelic odds ratio.</p>d<p>Confidence interval (CI).</p>e<p><i>P</i>-values were adjusted using the Bonferroni method for multiple tests.</p>f<p><i>P</i> -values were calculated using the Cochran-Armitage trend test.</p>g<p><i>P</i> -values were calculated using the χ² test.</p