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A partial loss of pigmentation in a human or other animal, resulting in white, pale, or patchy coloration of the skin, hair, fur, or feathers but not the eyes.

leu·cis′tic (-kĭs′tĭk) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
Leucism is a genetic abnormality of partial loss of pigmentation, causing individuals to appear partially or entirely white (Sage, 1962; Jehl, 1985; Lawrence, 1989).
Often you can see mild forms of leucism in garden birds such as blackbirds with one or two white feathers and some with even more white plumage.
An all-white fox has a condition called leucism (a partial lack of pigment).
In this work, we follow the proposal of Van Grouw (2006), who considers leucism as a partial or total lack of eumelanin and phaeomelanin due to an inherited disorder in pigment transfer, which causes fail in melanin deposition within cells, although maintaining pigments in the back of the eyeball but not in the iris.
This startling picture of the little owl, which is suffering from a problem known as leucism, was photographed close to Cleveland by Brian Martin.
Leucism occurs in quite a number of bird species, when the pigment in their genetic makeup is off.
Curator Richard Brown said: "We believe the baby has a condition called leucism, which means it's lacking in pigment resulting in the white looking coat.
More likely it's an example of flavism, similar but much rarer in birds than leucism, which causes white feathers in dark birds.
Abnormal white coloration manifests itself as albinism or leucism, and those terms are often used interchangeably, albeit erroneously (Curatolo 1979; McCardle 2012).
There are more than five million grey squirrels in Britain, but wildlife experts reckon fewer than one in a million are born with the leucism gene that makes them white.