Editing Myopia (section)

===Genetics===
A risk for myopia may be inherited from one's parents.<ref>{{cite web |title=Myopia (Nearsightedness) |url=http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/myopia |website=www.aoa.org |access-date=25 December 2019 |language=en}}</ref> [[Genetic linkage]] studies have identified 18 possible loci on 15 different [[chromosome]]s that are associated with myopia, but none of these loci is part of the candidate genes that cause myopia. Instead of a simple one-gene locus controlling the onset of myopia, a complex interaction of many mutated proteins acting in concert may be the cause. Instead of myopia being caused by a defect in a structural protein, defects in the control of these structural proteins might be the actual cause of myopia.<ref>{{cite journal | vauthors = Jacobi FK, Pusch CM | title = A decade in search of myopia genes | journal = Frontiers in Bioscience | volume = 15 | pages = 359–72 | date = January 2010 | issue = 1 | pmid = 20036825 | doi = 10.2741/3625 | doi-access = free }}</ref> A collaboration of all myopia studies worldwide identified 16 new loci for refractive error in individuals of European ancestry, of which 8 were shared with Asians. The new loci include candidate genes with functions in neurotransmission, ion transport, retinoic acid metabolism, extracellular matrix remodeling and eye development. The carriers of the high-risk genes have a tenfold increased risk of myopia.<ref>{{cite journal | vauthors = Verhoeven VJ, Hysi PG, Wojciechowski R, Fan Q, Guggenheim JA, Höhn R, MacGregor S, Hewitt AW, Nag A, Cheng CY, Yonova-Doing E, Zhou X, Ikram MK, Buitendijk GH, McMahon G, Kemp JP, Pourcain BS, Simpson CL, Mäkelä KM, Lehtimäki T, Kähönen M, Paterson AD, Hosseini SM, Wong HS, Xu L, Jonas JB, Pärssinen O, Wedenoja J, Yip SP, Ho DW, Pang CP, Chen LJ, Burdon KP, Craig JE, Klein BE, Klein R, Haller T, Metspalu A, Khor CC, Tai ES, Aung T, Vithana E, Tay WT, Barathi VA, Chen P, Li R, Liao J, Zheng Y, Ong RT, Döring A, Evans DM, Timpson NJ, Verkerk AJ, Meitinger T, Raitakari O, Hawthorne F, Spector TD, Karssen LC, Pirastu M, Murgia F, Ang W, Mishra A, Montgomery GW, Pennell CE, Cumberland PM, Cotlarciuc I, Mitchell P, Wang JJ, Schache M, Janmahasatian S, Janmahasathian S, Igo RP, Lass JH, Chew E, Iyengar SK, Gorgels TG, Rudan I, Hayward C, Wright AF, Polasek O, Vatavuk Z, Wilson JF, Fleck B, Zeller T, Mirshahi A, Müller C, Uitterlinden AG, Rivadeneira F, Vingerling JR, Hofman A, Oostra BA, Amin N, Bergen AA, Teo YY, Rahi JS, Vitart V, Williams C, Baird PN, Wong TY, Oexle K, Pfeiffer N, Mackey DA, Young TL, van Duijn CM, Saw SM, Bailey-Wilson JE, Stambolian D, Klaver CC, Hammond CJ | display-authors = 6 | title = Genome-wide meta-analyses of multiancestry cohorts identify multiple new susceptibility loci for refractive error and myopia | journal = Nature Genetics | volume = 45 | issue = 3 | pages = 314–8 | date = March 2013 | pmid = 23396134 | pmc = 3740568 | doi = 10.1038/ng.2554 }}</ref> Aberrant genetic recombination and gene splicing in the OPNLW1 and OPNMW1 genes that code for two retinal cone photopigment proteins can produce high myopia by interfering with refractive development of the eye.<ref>{{cite journal | vauthors = Neitz M, Neitz J | title = Intermixing the OPN1LW and OPN1MW Genes Disrupts the Exonic Splicing Code Causing an Array of Vision Disorders | journal = Genes | volume = 12 | issue = 8 | pages = 1180 | date = August 2021 | pmid = 34440353 | pmc = 8391646 | doi = 10.3390/genes12081180 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Li J, Gao B, Guan L, Xiao X, Zhang J, Li S, Jiang H, Jia X, Yang J, Guo X, Yin Y, Wang J, Zhang Q | display-authors = 6 | title = Unique Variants in OPN1LW Cause Both Syndromic and Nonsyndromic X-Linked High Myopia Mapped to MYP1 | journal = Investigative Ophthalmology & Visual Science | volume = 56 | issue = 6 | pages = 4150–4155 | date = June 2015 | pmid = 26114493 | doi = 10.1167/iovs.14-16356 }}</ref>

Human population studies suggest that contribution of genetic factors accounts for 60–90% of variance in refraction.<ref name="pmid17065484">{{cite journal | vauthors = Dirani M, Chamberlain M, Shekar SN, Islam AF, Garoufalis P, Chen CY, Guymer RH, Baird PN | display-authors = 6 | title = Heritability of refractive error and ocular biometrics: the Genes in Myopia (GEM) twin study | journal = Investigative Ophthalmology & Visual Science | volume = 47 | issue = 11 | pages = 4756–61 | date = November 2006 | pmid = 17065484 | doi = 10.1167/iovs.06-0270 | doi-access = free }}</ref><ref name="pmid18757506">{{cite journal | vauthors = Lopes MC, Andrew T, Carbonaro F, Spector TD, Hammond CJ | title = Estimating heritability and shared environmental effects for refractive error in twin and family studies | journal = Investigative Ophthalmology & Visual Science | volume = 50 | issue = 1 | pages = 126–31 | date = January 2009 | pmid = 18757506 | doi = 10.1167/iovs.08-2385 | doi-access = free }}</ref><ref name="pmid17724179">{{cite journal | vauthors = Peet JA, Cotch MF, Wojciechowski R, Bailey-Wilson JE, Stambolian D | title = Heritability and familial aggregation of refractive error in the Old Order Amish | journal = Investigative Ophthalmology & Visual Science | volume = 48 | issue = 9 | pages = 4002–6 | date = September 2007 | pmid = 17724179 | pmc = 1995233 | doi = 10.1167/iovs.06-1388 }}</ref><ref name="pmid26313004">{{cite journal | vauthors = Tkatchenko AV, Tkatchenko TV, Guggenheim JA, Verhoeven VJ, Hysi PG, Wojciechowski R, Singh PK, Kumar A, Thinakaran G, Williams C | display-authors = 6 | title = APLP2 Regulates Refractive Error and Myopia Development in Mice and Humans | journal = PLOS Genetics | volume = 11 | issue = 8 | pages = e1005432 | date = August 2015 | pmid = 26313004 | pmc = 4551475 | doi = 10.1371/journal.pgen.1005432 | doi-access = free }}</ref> However, the currently identified variants account for only a small fraction of myopia cases, suggesting the existence of a large number of yet unidentified low-frequency or small-effect variants, which underlie the majority of myopia cases.<ref name="pmid24385918">{{cite journal | vauthors = Gusev A, Bhatia G, Zaitlen N, Vilhjalmsson BJ, Diogo D, Stahl EA, Gregersen PK, Worthington J, Klareskog L, Raychaudhuri S, Plenge RM, Pasaniuc B, Price AL | display-authors = 6 | title = Quantifying missing heritability at known GWAS loci | journal = PLOS Genetics | volume = 9 | issue = 12 | pages = e1003993 | year = 2013 | pmid = 24385918 | pmc = 3873246 | doi = 10.1371/journal.pgen.1003993 | doi-access = free }}</ref>