Is Polymorphism Of CALM1 Gene/ER1 Gene Associated With Susceptibility Of Adolescent Idiopathic Scoliosis?

BackgroundAdolescent idiopathic scoliosis (AIS), a major rotatory asymmetry of the spine, is diagnosed after the onset of puberty. It can progress and severe cases may be complicated by restrictive pulmonary diseases, back pain, severe cosmetic deformity and psychosocial problems. Although rapid development of operative technique, because of uncertainty about cause of the disease, it's still difficult for the clinical doctor to prevent or control progress of the deformity, effectively.In the past decades, the vast range of etiological studies include genetic, molecular, histochemical, neurosurgical, cognitive, and dermatoglyphic aspects, and so on. However, all these works failed to reach an agreement. One of which, genetic research of AIS is brought into focus gradually in recent years.Although it's still not sure about the genetic methods of AIS, more and more evidence suggest that AIS may be multigenetic disease. As for the current methods of genetic research, usually, there are two kinds: the linkage analysis and the association analysis. The first is mainly for familial idiopathic scoliosis while the second is the kinless sufferer.Although there are more and more researchful report, however, the results were often self-contradiction. On the other side, as polymorphic phenotype (such as PUMC classification/Lenke classification, etc.), there are still no report about the association of genetic mechanism with different clinical classification.Objects1. To investigate the major effect of candidate genes (CALM1 Gene/ER1 gene) in mechanism of AIS.2. To examine the association between polymorphic phenotype and different candidate genes (CALM1 Gene/ER1 gene).Material and MethodsThis study included 100 patients with AIS (19 boys, 81 girls, mean age-15.11 years old), and 100 healthy controls(25 boys, 75 girls, mean age-15.55 years old). All of the subjects were from Peking Union Medical College Hospital. Height, menarche status, curve pattern, Cobb angle, and Risser sign in female patients were recorded. Genomic DNA was extracted from peripheral blood leukocytes of each subject who had signed informed consent, using QIAamp DNA Blood Mini Kit. There were 4 polymorphic loci, rs12885713 and rs5871 site in calmodulin 1 (CALM1) gene, rs2234693 and rs9340799 site in estrogen receptorα(ER1)gene, were analyzed. Firstly, PCR amplification and sequence of the segment contained SNP chosen from candidate genes. Then, SNPs were genotyped. Finally, we carried out statistical analysis for the association study with regards to polymophism of SNPs in both case and control group. At the same time, all of the patients were grouped according to PUMC classification, to investigate the association between different classification and AIS genetic mechanism.Results1. Epidemiologic Analysis(1) The corrected standing height of individuals in case group was significantly greater than that of control group (t=3.700, P=0.003).(2) AIS patients had earlier menarche than controls (Z=-3.956, P＜0.0001).2. SNP—AIS(1) Between group PUMCⅡAIS and controls, there are statistical difference on CALM1 gene rs12885713 site allele and ER1 gene rs2234693 site allele polymorphism (P value were 0.034, 0.014).(2) Between group thoracic curve and controls, there is difference on CALM1 gene rs5871 site allele polymorphism (P=0.035). (3) Between group lumbar curve and controls, there is difference on CALM1 gene rs12885713 site allele and ER1 gene rs9340799 site allele polymorphism(P value were 0.009 and 0.014).3. Genotype polymorphism—AIS(1) Between group Cobb angle≥40°and controls, there is difference on ER1 gene rs2234693 site genotype polymorphism (P＜0.0001)。(2) There were no any difference on genotype polymorphism between the other group AIS and controls (P＞0.05)。4. Combination of genotype and AISThere was statistical difference on CALM1 gene rs12885713 site genotype＋ER1 gene rs2234693 site genotype between group AIS and controls.Conclusion1. PUMCⅡAIS might be related to the the CALM1 gene rs12885713 site allele polymorphism and the ER1 gene rs2234693 site allele polymorphism.2. Thoracic curve AIS might be related to the CALM1 gene rs5871 site allele polymorphism.3. Lumbar curve AIS might be related to the the CALM1 gene rs12885713 site allele polymorphism and the ER1 gene XbaⅠ(rs9340799) site allele polymorphism.4. It was suggested that the PUMC classification is not only the criterion of treatment, but also the scientic combination of genetic mechanism and phenotype.5. The different clinical phenotype of AIS might be related to the different SNP site.6. The different combination of genotype might be related to the individual susceptibility to AIS.7. Although it's too early to get conclusion, it was suggested that different clinical phenotype of AIS might be related to different SNP site. It's the first time to research the genetic mechanism of AIS according to clinical classificiation.