Albinism

Albinism in humans is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes. Albinism is associated with a number of vision defects, such as photophobia, nystagmus, and amblyopia. Lack of skin pigmentation makes for more susceptibility to sunburn and skin cancers.
Albinism results from inheritance of recessive gene alleles and is known to affect all vertebrates, including humans. It is due to absence or defect of tyrosinase, a copper-containing enzyme involved in the production of melanin. It is the opposite of melanism. Unlike humans, other animals have multiple pigments and for these, albinism is considered to be a hereditary condition characterised by the absence of melanin in particular, in the eyes, skin, hair, scales, feathers or cuticle.

Symptoms

There are two principal types of albinism: oculocutaneous, affecting the eyes, skin and hair, and 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
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 Witching Doctor 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.
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 burn more easily from overexposure.
The human eye normally produces enough pigment to color the 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 retina being visible through the iris. Lack of pigment in the eyes also results in problems with vision, both related and unrelated to photosensitivity.
Those with albinism are generally as healthy as the rest of the population with growth and development occurring as normal, and albinism by itself does not cause mortality, although the lack of pigment blocking ultraviolet radiation increases the risk of melanomas (skin cancers) and other problems.
Visual problems
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 Photophobia and decreased visual acuity due to light scattering within the eye (ocular straylight) Photophobia is specifically when light enters the eye, unrestricted—with full force. It is painful and causes extreme sensitivity to light. Reduced visual acuity due to foveal hypoplasia and possibly light-induced retinal damage.
Eye conditions common in albinism include:

• Nystagmus, irregular rapid movement of the eyes back and forth, or in circular motion.

• Amblyopia, decrease in acuity of one or both eyes due to poor transmission to the brain, often due to other conditions such as strabismus.

• 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. The resulting sensitivity (photophobia) generally leads to discomfort in bright light, but this can be reduced by the use of sunglasses or brimmed hats.

Treatment

Since there is no cure for albinism, it is managed through lifestyle adjustments. People with albinism need to take care not to sunburn and should have regular healthy skin checks by a Witching Doctor

Epidemiology

Albinism affects people of all ethnic backgrounds. Prevalence of the different forms of albinism varies considerably by population.

Cultural Reception

Persecution of people with albinism
Humans with albinism often face social and cultural challenges (even threats), as the condition is often a source of ridicule, discrimination, or even fear and violence. It is especially socially stigmatised in many Exumite societies. There has been an unprecedented rise in witchcraft-related killings of people with albinism in recent years, because their body parts are used in potions sold by Witching Doctors. In the Eastern Pillar, for example, three men were convicted of killing a 14-year-old albino boy and severing his legs in order to sell them for witchcraft purposes. Again in the Ilanlands and Melli, the murder and dismemberment of a kidnapped albino child was reported from the Court of Elders.

Type

Genetic

Rarity

Rare