The promoter polymorphisms of melatonin receptor 1B gene in adolescent idiopathic scoliosis

Abstract

Objective To determine whether the promoter polymorphisms of melatonin receptor 1B gene (MTNR1B) associated with the predisposition and/or disease severity of adolescent idiopathic scoliosis (AIS). Methods Eight hundred and fourteen AIS patients and 651 normal controls were recruited in this study. The maximum Cobb angles of AIS patients were larger than 20 degrees. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)was performed to genotype two genetic variations (rs4753426、rs7941837) located in the MTNR1B promotor gene.ResultsFor rs4753426, the genotype frequencies were TT 6.5%, TC 41.5%, CC 52.0% in AIS patients, and TT 9.5%, TC 44.4%, CC 46.1% in controls; the allele frequencies were T 27.3%, C 73.7% in AIS patients and T 31.7%, C 68.3% in controls. The frequencies of genotype and allele of the rs4753426 were significantly different between AIS patients and controls (P=0.025, P=0.007, respectively). For rs7941837, the genotype frequencies were AA 21.2%, AT 50.2%, TT 28.6% in AIS patients, and AA 17.6%, AT 50.6%, TT 31.7% in controls; the allele frequencies were A 46.3%, T 53.7% in AIS patients, and A 43.0%, T 57.0% in controls. For rs7941837, both the frequencies of genotype and allele were not significant different between AIS patients and controls (P＞0.05). In the AIS patients who reached skeletal maturity or underwent corrective surgery, there was no difference in the mean maximum Cobb angles between the 2 variations of MTNR1B polymorphism.Conclusions Polymorphism of rs4753426 in the MTNR1B promoter gene is associated with the occurrence of AIS, suggesting MTNR1B is a predisposition gene rather than a modifying gene of AIS. Key words: Scoliosis; Adolescent