title: Phenotypic and genotypic correlation between myopia and intelligence.
abstract: Myopia, or near-sightedness, is our most common eye condition and the prevalence is increasing globally. Visual impairment will occur if uncorrected, whilst high myopia causes sight-threatening complications. Myopia is associated with higher intelligence. As both are heritable, we set out to examine whether there is a genetic correlation between myopia and intelligence in over 1,500 subjects (aged 14-18 years) from a twin birth cohort. The phenotypic correlation between refractive error and intelligence was -0.116 (p < 0.01) - the inverse correlation due to the fact that myopia is a negative refractive error. Bivariate twin modeling confirmed both traits were heritable (refractive error 85%, intelligence 47%) and the genetic correlation was -0.143 (95% CI -0.013 to -0.273). Of the small phenotypic correlation the majority (78%) was explained by genetic factors. Polygenic risk scores were constructed based on common genetic variants identified in previous genome-wide association studies of refractive error and intelligence. Genetic variants for intelligence and refractive error explain some of the reciprocal variance, suggesting genetic pleiotropy; in the best-fit model the polygenic score for intelligence explained 0.99% (p = 0.008) of refractive error variance. These novel findings indicate shared genetic factors contribute significantly to the covariance between myopia and intelligence.
authors.affiliation: Department of Ophthalmology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.|Department of Twin Research &Genetic Epidemiology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Katie M
authors.initials: KM
authors.lastname: Williams
authors.affiliation: Department of Twin Research &Genetic Epidemiology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Pirro G
authors.initials: PG
authors.lastname: Hysi
authors.affiliation: Department of Twin Research &Genetic Epidemiology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Yonova-Doing
authors.affiliation: Department of Ophthalmology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Mahroo
authors.affiliation: Unit of Genetic Epidemiology &Bioinformatics, Department of Epidemiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, The Netherlands.
authors.forename: Harold
authors.initials: H
authors.lastname: Snieder
authors.affiliation: Department of Ophthalmology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.|Department of Twin Research &Genetic Epidemiology, King's College London, 3rd Floor Block D South Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hammond
mesh_terms: D000293:Adolescent; D005260:Female; D056726:Genetic Association Studies; D015894:Genome, Human; D006801:Humans; D007360:Intelligence / Q000235:genetics*; D016014:Linear Models; D008297:Male; D020412:Multifactorial Inheritance / Q000235:genetics; D009216:Myopia / Q000235:genetics*; D012030:Refractive Errors; D012307:Risk Factors; D014427:Twins / Q000235:genetics