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Mutations in a single copy of SNAI2 have also been found to cause patches of hair depigmentation without any other symptoms. [25] Type 2E is caused by an autosomal dominant mutation in the gene SOX10. [4] Rarely, a mutation in a gene other than those currently known may be responsible for a Waardenburg syndrome with features of type 2.
The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). [3] In humans, an increase of melanin production in the eyes indicates hyperplasia of the iris tissues, whereas a lack of melanin indicates hypoplasia. The term is derived from Ancient Greek: ἕτερος, héteros "different" and χρῶμα, chrôma "color ...
[56] [57] However, more recent ancient DNA research has identified human remains much older than the Neolithic period which possess the OCA2 mutation for blue eyes. It is now believed that the OCA2 allele responsible for blue eyes dates back to the migration of modern humans out of Africa roughly 50,000 years ago, and entered Europe from ...
A mutation in the HERC2 gene adjacent to OCA2, affecting OCA2's expression in the human iris, is found common to nearly all people with blue eyes. It has been hypothesized that all blue-eyed humans share a single common ancestor with whom the mutation originated. [10] [11] [12]
MWS and LWS cones are most responsible for visual acuity as they are concentrated in the fovea centralis region of the retina, which constitutes the very center of the visual field. Blue cone monochromacy is a severe condition in which the cones sensitive to red or green light are missing or defective, and only S-cones sensitive to blue light ...
Hans Eiberg (born 8 April 1945) is a Danish geneticist, known for his discovery of the genetic mutation causing blue eyes.. Hans Eiberg graduated as a M.Sc. in 1970. He has worked with genetics at the Institute for Medical Biochemistry and Genetics of Copenhagen University since 1971, and became an associate professor at the institute in 1975.
Individuals with this condition usually start showing signs of nyctalopia (also known as night-blindness) during their early childhood, increase in sensitivity to blue light, progressive decrease of visual acuity in both eyes, cataract, peripheral vision loss, vitreous liquefaction and detachment, clumped pigment deposits of the fundus, either peripheral or central retinoschisis, cystic ...
In contrast, mutations in the gene BAP1 are strongly linked to metastatic spread and patient survival. [17] Incidence of posterior uveal melanoma is highest among people with light skin and blue eyes. Other risk factors, such as blue light exposure and arc welding, have been put forward, but are still debated in the field.