The polymorphisms of melatonin receptor 1B gene (MTNR1B) (rs4753426 and rs10830963) and susceptibility to adolescent idiopathic scoliosis: a meta-analysis

To determine whether MTNR1B rs4753426 and rs10830963 polymorphisms are correlated with AIS. Adolescent idiopathic scoliosis (AIS) is the most common form of spinal deformity, while its etiology remains uncertain. Melatonin receptor 1B (MTNR1B) gene polymorphisms have been found to be significantly associated with AIS risk; however, some of these results are controversial. An systematic online search was performed using PubMed, EMBASE, Web of Science and the Cochrane Library to identify case-control studies investigating the relationship between MTNR1B rs4753426 and rs10830963 polymorphisms and the susceptibility of AIS. The pooled odds ratio (OR) with 95 % confidence interval (95 % CI) was calculated to assess the associations, and subgroup meta-analyses were performed according to the ethnicity of the study populations. A total of five studies involving 2395 cases and 3645 controls met the inclusion criteria after assessment by two reviewers. Overall, no significant associations were found between MTNR1B rs4753426 polymorphism and AIS risk (C vs. T: OR = 1.11, 95 % CI 0.94-1.30, P = 0.21; CC vs. TT: OR = 1.15, 95 % CI 0.97-1.36, P = 0.12; CT vs. TT: OR = 1.14, 95 % CI 0.97-1.35, P = 0.10; CC/CT vs. TT: OR = 1.14, 95 % CI 0.98-1.33, P = 0.09; CC vs. CT/TT: OR = 1.10, 95 % CI 0.84-1.45, P = 0.48), as well as the MTNR1B rs10830963 polymorphism (G vs. C: OR = 0.99, 95 % CI 0.88-1.12, P = 0.91; GG vs. CC: OR = 0.99, 95 % CI 0.74-1.33, P = 0.96; CG vs. CC: OR = 1.00, 95 % CI 0.84-1.18, P = 0.88; GG/CG vs. CC: OR = 0.99, 95 % CI 0.84-1.17, P = 0.93; GG vs. CG/CC: OR = 0.99, 95 % CI 0.75-1.30, P = 0.92). When stratified by ethnicity, there were no significant associations between MTNR1B rs4753426 and MTNR1B rs10830963 polymorphisms and AIS risk in either Asian or Caucasian populations. MTNR1B rs4753426 and MTNR1B rs10830963 polymorphisms are not obviously associated with risk of AIS in either Asian populations or Caucasian populations.