Background
The aim was to review all published studies that investigated the association between MYOC.mt1 polymorphism and the risk of primary open-angle glaucoma (POAG).
Material and Method
Electronic databases were searched for relevant articles in English. Inclusion and exclusion criteria were established according to the criteria of the Cochrane Methods Group. Studies were included if participants were patients with POAG (adult- or juvenile-onset), had extractable data on both genotypes of MYOC.mt1, phenotypes of severity, and reasonable controls. Statistical analysis was performed using SPSS 13.0 for Windows and RevMan 4.2. Four case-control studies of 835 cases and 530 controls were included in the meta-analysis.
Results
The pooled odds ratio (OR) to develop POAG with and without MYOC.mt1 from a fixed-effects model was 1.06 (95%CI: 0.81-1.38, P=0.67), i.e. MYOC.mt1 carriers did not have significantly higher risk of developing POAG than non-carriers. There was also no significant association between the -1000G allele and increased risk (OR=1.05, 95%CI: 0.83-1.32, P=0.71). Comprehensive summarization was done to determine the influence of MYOC.mt1 on the severity of optic disk changes and visual function loss in POAG cases. There was evidence of publication bias from funnel-plot asymmetry and Egger's test.
Conclusions
Evidence for an association between MYOC.mt1 and the risk of POAG is limited. These results suggest that MYOC.mt1 polymorphism does not have significant influence on the risk of POAG development or its severity. However, the evidence of publication bias suggests that more large prospective cohort studies with precise design are required to confirm an association between MYOC.mt1 and POAG.

Keywords: Polymorphism, Genetic, Promoter Regions, Genetic - genetics, Glycoproteins - genetics, Glaucoma, Open-Angle - genetics, Eye Proteins - genetics, Genetic Predisposition to Disease, Cytoskeletal Proteins - genetics, Alleles