Editing Color blindness (section)

====Genetics of blue–yellow color blindness====
Congenital blue–yellow color blindness is a much rarer form of color blindness including tritanopia/tritanomaly. These conditions are mediated by the [[OPN1SW]] gene on [[Chromosome 7]] which encodes the S-opsin protein and follows autosomal dominant inheritance.<ref name="Sharpe1999"/> The cause of blue–yellow color blindness is not analogous to the cause of red–green color blindness, i.e. the peak sensitivity of the S-opsin does not shift to longer wavelengths. Rather, there are 6 known point mutations of OPN1SW that degrade the performance of the S-cones.<ref name="RCM2020">{{cite book |last1=Rodriguez-Carmona |first1=Marisa |last2=Patterson |first2=Emily J. |chapter=Photoreceptors, Color Vision |title=Encyclopedia of Color Science and Technology |date=2020 |pages=1–7 |doi=10.1007/978-3-642-27851-8_277-3 |isbn=978-3-642-27851-8 |s2cid=226504635 |chapter-url=https://openaccess.city.ac.uk/id/eprint/23584/1/Photoreceptors%20Color%20Vision_submitted%20to%20CRO.pdf |access-date=18 December 2023 |archive-date=2 December 2023 |archive-url=https://web.archive.org/web/20231202184422/https://openaccess.city.ac.uk/id/eprint/23584/1/Photoreceptors%20Color%20Vision_submitted%20to%20CRO.pdf |url-status=live }}</ref> The OPN1SW gene is almost invariant in the human population. Congenital tritan defects are often progressive, with nearly normal trichromatic vision in childhood (e.g. mild tritanomaly) progressing to dichromacy (tritanopia) as the S-cones slowly die.<ref name="RCM2020"/> Tritanomaly and tritanopia are therefore different penetrance of the same disease, and some sources have argued that tritanomaly therefore be referred to as incomplete tritanopia.<ref name="Sharpe1999">{{cite book |last1=Sharpe |first1=LT |last2=Stockman |first2=A |last3=Jägle |first3=H |last4=Nathans |first4=J |title=Color vision: From genes to perception |date=1999 |page=351 |url=http://www.cvrl.org/people/stockman/pubs/1999%20Genetics%20chapter%20SSJN.pdf |chapter=Opsin genes, cone photopigments, color vision, and color blindness. |quote=True cases of tritanomaly, as distinct from partial or incomplete tritanopia, have never been satisfactorily documented. Although the separate existence of tritanopia and tritanomaly, with different modes of inheritance, has been postulated, it now seems more likely that tritanomaly does not exist, but rather has been mistaken for incomplete tritanopia. |access-date=16 December 2023 |archive-date=3 October 2024 |archive-url=https://web.archive.org/web/20241003080812/http://www.cvrl.org/people/stockman/pubs/1999%20Genetics%20chapter%20SSJN.pdf |url-status=live }}</ref>