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Gary Bargary, Adam Lawrance-Owen, Patrick Goodbourn, Jenny Bosten, John Mollon; A potassium ion channel associated with variation in the accuracy of ocular tracking. Journal of Vision 2014;14(15):46. doi: https://doi.org/10.1167/14.15.46.
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© ARVO (1962-2015); The Authors (2016-present)
Smooth pursuit eye movements differ from saccades in their vulnerability to barbiturates and in their frequent impairment in schizophrenia. In a whole-genome association study of 979 healthy young adults, we measured the accuracy of smooth pursuit movements using a head-mounted infra-red eye tracker (JAZZ-novo, Ober Consulting). Targets moved horizontally at a speed that was constant within a block (10°/s, 20°/s or / 30°/s). We found a strong association (P = 3.5 x 10–11) between the root mean square error (RMSE) in this ocular tracking task and a locus in the chromosomal region 1q42.2. The most strongly associated marker (rs701232) lies in an intron of the gene KCNK1, which encodes the two-pore-domain potassium ion channel K2P1. The association was confirmed by a permutation analysis, which gave a genome-wide probability value of 0.0039. Within our sample of participants, RMSE in ocular tracking was significantly correlated with performance on a number of psychophysical tasks, including detection of coherent motion (0.16 <ρ< 0.34, P<< 0.001). None of these perceptual measures were themselves associated with rs701232; and when we used performance on the coherent-motion task as a covariate in the GWAS for smooth pursuit, the association with rs701232 was not weakened (P = 5.38 x 10–12). We conclude that individual differences in perceptual ability are unlikely to be the source of the effect of rs701232 on ocular tracking. Supported by the Gatsby Charitable Foundation (GAT2903).
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