Objective: To investigate the major effect of the candidate genes, calmodulin 1 (CALM1) and growth hormone receptor (GHR) gene, in mechanism of adolescent idiopathic scoliosis (AIS) and to evaluate the cross-influence between the polymorphism of the candidates genes and risk factors of AIS.
Methods: Peripheral blood samples were collected from 30 AIS patients, 6 boys and 24 girls, aged 15.7, and 30 gender and age-matched controls. Genomic DNA was extracted. PCR amplification and sequencing of the segments containing SNPs chosen from candidate genes were conducted. The SNPs were genotyped then. Statistical analysis was conducted. Questionnaire survey was conducted in terms of the risk factors.
Results: (1) The AIS patients had higher corrected standing height and an earlier growth spurt than the controls. (2) The frequencies of CC genotype of CALM1 gene at -16C > T locus and homozygous genotype of GHR gene at exon 10 I526L were significantly higher in the AIS patients than in the controls. (3) The frequencies of SNP03G-05A and SNP03G-05C haplotypes of GHR gene were significantly higher in the AIS patients than in the controls. (4) The frequency of PPGG (PP = homozygous genotype of GHR gene at I526L, GG = homozygous genotype of MTNR1B gene at rs1562444 locus) of the AIS patients was significantly higher than that of the controls. (5) The AIS patients who had homozygous genotype of GHR gene at I526L had an earlier growth spurt and higher standing height than those who had heterozygous genotype.
Conclusion: The -16C > T polymorphism at the promoter region of CALM1 gene and the homozygous genotype of GHR gene at I526L may be associated with high susceptibility to AIS.