Genetics of myopia.

Myopia research and correction is a World Health Organization priority, because myopia development seems to be attributable to environment, behavioral patterns, and genetic factors, which may all be subject to modification.[12] Around 15% of the Middle Eastern population suffer from diagnosed myopia, which frequently stays uncorrected due to cultural disincentives.[3] Uncorrected myopia is a major reason for traffic accidents[4] and has also been reported for night myopia >0.75D in the region. Apart from the refractive impairment, axial myopia bears the risk of retinal detachment and is a potentially blinding condition.

Genetic research has resulted in the identification of linkage regions for myopia (2q, 4q, 7q, 12q, 15q,17q, 18p, 22q, and Xq), and genes on 7p15, 7q36, and 22q11 were reported to control myopia.[5] Only recently, research has focused on the vitamin D receptor wherein polymorphisms have been found associated with myopia. In the zebrafish, nonsense mutations in low-density lipoprotein receptor-related protein 2 (lrp2), which serves also as an endocytic receptor for the vitamin D binding protein, has been linked to the development of high myopia (and glaucoma). In humans, polymorphisms of the vitamin D receptor and the group-specific component were linked to moderate myopia, corroborating preliminary findings of lower vitamin D blood levels in myopes.

Besides other important articles in this issue of OJO, research reported on the vitamin D receptor gene start codon (fok1) further details the significance of vitamin D involvement in myopia and is another step on the long road to understanding genetics in myopia.