Purpose: To identify heritable genetic factors altering susceptibility to refractive error in the general population.
Methods: This was a genetic association study of refractive error investigating genetic polymorphisms in regions previously reported through linkage. Two study panels were drawn from the British 1958 Birth Cohort, composed of 2211 persons 44 years of age at the time of visit. Two main outcomes were considered: refractive error as a continuous outcome (spherical equivalent) and myopia as a diagnosis (defined as spherical equivalent equal to or worse than-1.00 diopter). Genotyping was initially performed in 1188 subjects from the outer tertiles of the population distribution, using customized arrays of single nucleotide polymorphisms (SNPs) saturating regions of previously reported highly significant linkage. In a second stage, SNPs most significantly associated were validated in 1023 more persons. Findings were investigated further through human fetal expression studies.
Results: Polymorphisms within the SERPINI2 gene were associated with refractive error in two different European subgroups from the 1958 British Birth Cohort (meta-analysis P = 7.4E-05 for rs9810473). Association was also significant for myopia (best association: OR = 0.80; 95% CI, 0.69-0.93; P = 0.003 for rs10936538). Expression profiling of SERPINI2 revealed that the gene is expressed in the retina and in other eye and CNS tissues.
Conclusions: The novel association of SERPINI2 with refractive error and myopia is suggestive of a possible link between physiological pathways controlling eye growth and development and those controlling glucose metabolism. The findings indicate that SERPINI2 is a promising candidate for further investigations of the genetic susceptibility to myopia.