Single nucleotide polymorphisms in pigmentation‐related dopachrome tautomerase and melanocortin‐1 receptor genes are associated with wet age‐related macular degeneration in a Finnish cohort

Abstract

AbstractPurpose: Melanin in intracellular organelles, melanosomes, protects the retinal pigment epithelium from ultraviolet radiation and oxidative stress (OS). However, despite the role of OS in the development of age‐related macular degeneration (AMD), the effect of pigmentation‐related genes on the risk of AMD onset is unclear.Methods: Finnish wet AMD patients and control subjects were genotyped for selected pigmentation‐related genes. 26 selected variants for tyrosinase (TYR), tyrosinase‐related protein 1 (TYRP1), dopachrome tautomerase (DCT), melanocortin‐1 receptor (MC1R), microphthalmia‐associated transcription factor (MITF), and orthodenticle homeobox‐2 (OTX2) were analysed using the Sequenom iPlex platform (Sequenom, Hamburg, Germany). Binary logistic regression analyses were performed to find genetic associations.Results: An intronic variant rs1407995 (T > C) of the DCT gene and a two base pair deletion variant rs3212351 (AT > del) in the regulatory region of the MC1R gene were associated with wet AMD in a crude recessive model (OR = 3.250, 95% CI = 1.036–10.195, p = 0.043 and OR = 1.714, 95% CI = 1.004–2.924, p = 0.048, respectively). The age‐ and gender‐adjusted recessive model revealed a stronger association of rs1407995 to AMD (OR = 4.514, 95% CI = 1.300–15.669, p = 0.018), whereas rs3212351 was no longer statistically significant (OR = 1.612, 95% CI = 0.923–2.819, p = 0.093).Conclusions: Several mutations in DCT and MC1R genes are known to associate with the blond or red hair phenotype with increasing ratio of red pro‐oxidant pheomelanin to protective brown eumelanin pigments. Furthermore, MC1R has been linked to the regulation of ocular inflammation, another key event in the pathogenesis of AMD. In conclusion, two polymorphisms in genes regulating melanin production and oxidative balance in pigmented cells were observed in a Finnish cohort evoking interest in their role in AMD onset.