Editing Albinism in humans (section)

==Signs and symptoms==
[[File:Albinistic girl papua new guinea.jpg|thumb|left|Girl with albinism from [[Papua New Guinea]]]]There are two principal types of albinism: [[Oculocutaneous albinism|oculocutaneous]], affecting the eyes, skin and hair, and [[Ocular albinism|ocular]], affecting the eyes only.

There are different types of oculocutaneous albinism depending on which gene has undergone mutation. With some there is no pigment at all. The other end of the spectrum of albinism is "a form of albinism called rufous oculocutaneous albinism, which usually affects dark-skinned people".<ref>{{Cite web |last=<!--Staff writer(s); no by-line.--> |date=October 2015 |title=oculocutaneous albinism |url=http://ghr.nlm.nih.gov/condition/oculocutaneous-albinism |access-date=10 November 2017 |website=Genetics Home Reference |publisher=[[U.S. National Library of Medicine]], [[National Institutes of Health]] |location=Bethesda, Maryland}}{{tertiary source|date=November 2017}}</ref>

According to the US [[National Organization for Albinism and Hypopigmentation]], "With ocular albinism, the color of the iris of the eye may vary from blue to green or even brown, and sometimes darkens with age. However, when an optometrist or ophthalmologist examines the eye by shining a light from the side of the eye, the light shines back through the iris since very little pigment is present."<ref>{{Cite web |title=Information Bulletin – Ocular Albinism |url=http://www.albinism.org/site/c.flKYIdOUIhJ4H/b.9260357/k.A94A/Information_Bulletin__Ocular_Albinism.htm |url-status=dead |archive-url=https://web.archive.org/web/20170312070207/http://www.albinism.org/site/c.flKYIdOUIhJ4H/b.9260357/k.A94A/Information_Bulletin__Ocular_Albinism.htm |archive-date=12 March 2017 |access-date=11 March 2017 |publisher=National Organization for Albinism and Hypopigmentation}}</ref>

Because individuals with albinism have skin that entirely lacks the dark pigment melanin, which helps protect the skin from the sun's [[ultraviolet]] [[radiation]], their skin can [[sunburn|burn]] more easily from overexposure.<ref name="Atlas of Genetic Diagnosis">{{Cite book |last=Chen |first=Harold |url=https://books.google.com/books?id=2VcdAXJ_dZkC&q=Albinism&pg=PA36 |title=Atlas of genetic diagnosis and counseling |date=2006 |publisher=Humana Press |isbn=9781588296818 |location=Totowa, New Jersey |pages=37–40 |access-date=22 July 2010}}</ref>

The human eye normally produces enough pigment to color the [[Iris (anatomy)|iris]] blue, green or brown and lend opacity to the eye. In photographs, those with albinism are more likely to demonstrate "red eye", due to the red of the [[retina]] being visible through the iris. Lack of pigment in the eyes also results in problems with vision, both related and unrelated to [[photosensitivity]].<ref>{{Cite book |last=Khanna |first=Pragya |url=https://books.google.com/books?id=ByQ07W-RxIwC |title=Essentials of Genetics |date=30 December 2013 |publisher=I. K. International |isbn=9789380026343}}</ref>

Those with albinism are generally as healthy as the rest of the population (but see related disorders below), with growth and development occurring as normal, and albinism by itself does not cause mortality,<ref name="eMedicine1" /> although the lack of pigment blocking [[ultraviolet]] [[radiation]] increases the risk of melanomas (skin cancers) and other problems.<ref>{{Cite book |last=Richter |first=Roxane |url=https://books.google.com/books?id=Ik8DDgAAQBAJ |title=Witchcraft as a Social Diagnosis: Traditional Ghanaian Beliefs and Global Health |last2=Flowers |first2=Thomas |last3=Bongmba |first3=Elias |date=2017 |publisher=Lexington Books |isbn=9781498523196}}</ref>

===Visual problems===
[[Image:Mali Salif Keita2 400.jpg|thumb|upright=0.8|[[Mali]]an [[Mandinka people|Mandinka]] singer [[Salif Keita]] with albinism]]
Development of the optical system is highly dependent on the presence of melanin. For this reason, the reduction or absence of this pigment in people with albinism may lead to:
* Misrouting of the retinogeniculate projections, resulting in abnormal [[decussation]] (crossing) of optic nerve fibres<ref name="Atlas of Genetic Diagnosis" />
* [[Photophobia]] and decreased [[visual acuity]] due to light scattering within the eye ([[ocular straylight]])<ref name="Atlas of Genetic Diagnosis" /><ref>{{Cite journal |last=Kruijt |first=Bastiaan |last2=Franssen |first2=Luuk |last3=Prick |first3=Liesbeth J. J. M. |last4=Van Vliet |first4=Johannes M. J. |last5=Van Den Berg |first5=Thomas J. T. P. |date=2011 |title=Ocular Straylight in Albinism |journal=Optometry and Vision Science |volume=88 |issue=5 |pages=E585–592 |doi=10.1097/OPX.0b013e318212071e |pmid=21358444 |s2cid=24992321}}</ref>
* Reduced visual acuity due to [[Macular hypoplasia|foveal hypoplasia]] and possibly light-induced [[retina]]l damage.<ref name="Atlas of Genetic Diagnosis" />

Eye conditions common in albinism include:
* [[Nystagmus]], irregular rapid movement of the eyes back and forth, or in circular motion.<ref name="Atlas of Genetic Diagnosis" />
* [[Amblyopia]], decrease in acuity of one or both eyes due to poor transmission to the brain, often due to other conditions such as [[strabismus]].<ref name="Atlas of Genetic Diagnosis" />
* [[Optic nerve hypoplasia]], underdevelopment of the optic nerve.

The improper development of the [[retinal pigment epithelium]] (RPE), which in normal eyes absorbs most of the reflected sunlight, further increases glare due to light scattering within the eye.<ref name="Optometry Albinism">{{Cite web |last=Sowka |first=Joseph W. |last2=Gurwood |first2=Andrew S. |last3=Kabat |first3=Allan G. |date=15 April 2009 |title=Albinism |url=https://www.reviewofoptometry.com/CMSDocuments/2009/9/ro0409_handbook.pdf |url-status=live |archive-url=https://web.archive.org/web/20150824100916/https://www.reviewofoptometry.com/CMSDocuments/2009/9/ro0409_handbook.pdf |archive-date=24 August 2015 |access-date=10 November 2017 |website=The Handbook of Ocular Disease Management: Supplement to Review of Optometry |publisher=Jobson Medical Information |pages=63A–65A |via=ReviewOfOptometry.com |edition=11th |location=New York}}<!--Note: Albinism has been removed, for some reason, from at least the 12th (2010) through 18th (2016) editions.--></ref> The resulting sensitivity (photophobia) generally leads to discomfort in bright light, but this can be reduced by the use of sunglasses or brimmed hats.<ref name="Facts Albinism" />