Association study of single nucleotide polymorphism in tryptophan hydroxylase 1 gene with adolescent idiopathic scoliosis: A meta-analysis

BACKGROUND: Adolescent idiopathic scoliosis is a common spinal deformity among children and adolescents worldwide with its etiology uncertain. Over a decade, a single nucleotide polymorphism rs10488682 in tryptophan hydroxylase 1 (TPH1) gene has been investigated in several association studies. We perform this study to summarize the current evidence of TPH1 rs10488682 polymorphisms and adolescent idiopathic scoliosis (AIS). METHODS: Six databases were systematically searched: PubMed, Embase, Cochrane Library, Web of Science, Chinese Biomedical Literature, and Wanfang database. Eligible case–control studies related to TPH1 and AIS were selected. Reference lists of them were reviewed for more available studies. Two authors independently screened and evaluated the literature and extracted data. The odds ratios and 95% confidence intervals were derived in association tests. Subgroup analysis was conducted by ethnicity. Sensitivity analysis was performed to examine the stability of the overall results. RESULTS: A total of 1006 cases and 1557 controls in 3 independent studies were included for meta-analysis. Statistical significance was discovered in heterozygote model (AT vs AA: OR = 1.741, 95%Cl = 1.100–2.753, P = .018 < .05, I(2) = 0%), recessive model (AA vs AT + TT: OR = 0.640, 95%Cl = 0.414–0.990, P = .045 < .05, I(2) = 0%) and over-dominant model (AT vs AA + TT: OR = 1.366, 95%Cl = 1.115–1.673, P = .003 < .05, I(2) = 84.7%) in overall populations. Similar associations were also found in the Caucasian population. No significant associations were found in other genotypic comparisons and allelic comparisons. CONCLUSIONS: Statistically significant correlations were discovered between the TPH1 rs10488682 polymorphisms and AIS. Heterozygous AT genotype seems to be risky with an over-dominant effect. Ethnicity appears to modify the disease association. REGISTRATION: Not applicable.