Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity. We previously conducted a genome-wide association study (GWAS) and detected two loci associated with AIS. To identify additional loci, we extended our GWAS by increasing the number of cohorts (2,109 affected subjects and 11,140 control subjects in total) and conducting a whole-genome imputation. Through the extended GWAS and replication studies using independent Japanese and Chinese populations, we identified a susceptibility locus on chromosome 9p22.2 (p = 2.46 × 10(-13); odds ratio = 1.21). The most significantly associated SNPs were in intron 3 of BNC2, which encodes a zinc finger transcription factor, basonuclin-2. Expression quantitative trait loci data suggested that the associated SNPs have the potential to regulate the BNC2 transcriptional activity and that the susceptibility alleles increase BNC2 expression. We identified a functional SNP, rs10738445 in BNC2, whose susceptibility allele showed both higher binding to a transcription factor, YY1 (yin and yang 1), and higher BNC2 enhancer activity than the non-susceptibility allele. BNC2 overexpression produced body curvature in developing zebrafish in a gene-dosage-dependent manner. Our results suggest that increased BNC2 expression is implicated in the etiology of AIS.

Shoulder balance is one of the key components to the body deformity in adolescent idiopathic scoliosis (AIS) patients with double thoracic curve and shoulder cosmesis plays an important role in patients' satisfaction of surgical outcomes. Up to now, only radiographic parameters were used to evaluate the shoulder balance in literatures; no corresponding cosmetic parameters have been developed to evaluate the cosmetic shoulder balance. Meanwhile, we often confronted that perfect radiographic shoulder balance was achieved, but the patients complained about the residual cosmetic deformity. This phenomenon implied that discrepancy may exist between radiographic shoulder balance and cosmetic shoulder balance. The present study was carried out to investigate the correlation between radiographic and clinical cosmetic shoulder balance in AIS patients with double thoracic curve. Thirtyfour AIS patients were recruited for this study. All the patients had a double thoracic curve. Six cosmetic parameters--inner shoulder height (SHi), outer shoulder height (SHo), shoulder area index 1 (SAI1), shoulder area index 2 (SAI2), shoulder angle (a1) and axilla angle (a2) were developed and measured on the standing photographs. Also, seven radiographic parameters--T1 tilting (T1), first rib angle (FRA), clavicle angle (CA), coracoid process height (CPH), clavicle-rib cage intersection (CRCI), first rib-clavicle height (FRCH), trapezius length (TL) were measured on the standing posterior-anterior radiographs. Correlation analysis was made between cosmetic parameters and radiographic parameters. SHi was found to be significantly correlated with T1, FRA, CA, CPH, CRCI (P \ 0.05), among which FRA had the highest correlation coefficient. SHo was found to be significantly correlated with T1, FRA, CA, CPH, CRCI, FRCH (P \ 0.05), among which CRCI had the highest correlation coefficient. However, none of the correlation coefficient was greater than 0.8. The correlation coefficients between radiographic parameters and SAI1, SAI2, a1, a2 were also below 0.8 that were similar with SH. The results indicated that radiographic parameters could only partially reflect the shoulder cosmetic appearances. However, none of the existing parameters can accurately reflect the shoulder cosmetic appearance. As cosmesis is critical important to patients' satisfaction, spine surgeons should pay more attention to the cosmetic shoulder balance rather than radiographic shoulder balance.

Purpose To investigate the prevalence of degenerative lumbar scoliosis (DLS) in Chinese Han population, as well as its correlation with age, gender, bone mineral density (BMD), and body mass index (BMI); and to determine factors that might affect the curve severity. Methods A prospective study was performed on adults visiting the dual-energy X-ray absorption clinics for physical examination from January 2011 to March 2012. 2,395 subjects aged older than 40 years and having no history of previous spinal trauma, surgeries or scoliosis, were enrolled in this study. A logistic regression analysis was performed to determine the independent variables related to the presence of scoliosis. Besides, the relationship between curve severity and these variables was also analyzed with partial linear correlation analysis. Results The prevalence of DLS was approximately 13.3 %. The logistic regression analysis showed that age, T score, and gender all had remarkable correlation with the occurrence of DLS, with the odd ratios being 4.2, 1.5, and 1.6, respectively. According to the receiver operating characteristics curve, the best dividing point for age and T score of female subjects was 65 and -2.0, respectively. Partial linear correlation analysis indicated that there existed no obvious correlation between the above variables and the severity of scoliosis. Conclusion The prevalence of DLS in Chinese Han population aged older than 40 years was approximately 13.3 %, which had a significant correlation with age, gender, and BMD. Osteopenia, gender of female, and aged older than 65 years could contribute to the presence of DLS. The curve severity was not associated with age, gender, BMI, or BMD.

Smartphone-aided measurement for Cobb angle showed excellent reliability and efficiency. It is suggested to popularize the use of this method in clinical practice.