Albinism: what is it and what are its causes in people and animals?
Albinism is a set of inherited disorders in which there is little or no production melanin pigment in the body. It is a chemical substance whose amount determines the color of the skin, hair and eyes. This condition can be seen in people, but there are also many cases of occurrence in animals.
Melanin intervenes in the development of the optic nerves, this is the reason that it responds to vision problems in albino individuals. Also, these people are sensitive to the effects of the sun, consequently, they are the population with the highest risk of contracting skin cancer.
Signs and traits of albinism
Physically albino people can be recognized by their skin, hair and eye color. In this sense, they present the symptoms mentioned below.
The most identifiable trait of albinism is very light white skin compared to siblings. Exposure to the sun can cause freckles, moles with or without pigmentation (moles without pigmentation are pink). As well as sunburn and are people unable to tan.
In some people with albinism, the pigmentation of the skin never changes. While, in others, changes can be seen in adolescence, which causes a slight pigmentation.
Hair color may vary from very white to brown. In general, people of African descent can have hair of yellow, reddish or brown color. Hair pigmentation can also increase as the individual approaches adulthood. Or it is due to exposure to minerals found in water and the environment, therefore, it will appear darker with age.
The color of the eyelashes and eyebrows are usually very pale, while the tonality of the eyes can vary from a very light blue to brown and can change with age.
The lack of melanin in the iris of the eye makes it appear translucent. This means that it cannot completely block the light that can enter the eye.
Vision impairment is a characteristic condition in all types of albinism. Also the rapid and involuntary lateral movement, the inability to focus both eyes on one point, the extreme nearsightedness and farsightedness, sensitivity, among other symptoms.
Causes of albinism
Several genes are responsible for providing one of the various proteins involved in the production of melanin. This chemical is made by cells called melanocytes in the eyes and skin.
Albinism is caused by a mutation in some of these genes, and different types can develop. The alteration can result in a complete absence of melanin or a significantly reduced amount.
Types of albinism
The different types of albinisms are classified according to the way it was inherited and the gene that is affected.
Oculocutaneous albinism (OCA)
It is the most frequent type, autosomal recessive inheritance, means that a person inherited two exact copies of a mutated gene, one from each parent. It results as a consequence of a mutation in one of the seven genes, labeled from OCA1 through OCA7. OCA causes a decrease in pigmentation of the skin, hair and eyes and with it, vision problems. The amount of melanin varies according to the type of gene, as well as the color of the mentioned traits.
It is mainly limited to the eyes, which causes vision problems. The most common form is type 1, inherited by a genetic mutation on the X chromosome. This ocular albinism can be caused by a mother who carries a mutated X gene to her child (X-linked recessive inheritance). It is usually exclusively an albinism that occurs in men and it is much less common than oculocutaneous.
On the other hand, albinisms related to very rare syndromes of genetic predisposition can arise. An example of this is the syndrome of Hermansky-Pudlak which includes bruises and intestinal and lung diseases. Syndrome Chédiak – Higashi it also includes a form of oculocutaneous albinism. As well as immune problems with recurring infections, neurological abnormalities, and other serious problems.
Can it be reversed?
There is no cure for albinism, this is because it is a genetic disorder that cannot be corrected. However, people with it can take steps to protect their skin and eyes.
- Eye care
A specialist is required to perform an annual eye exam indicating the formula for prescription corrective lenses. Surgery to correct the squint may contribute to less noticeable disease, but this will depend on the ophthalmologist's considerations.
- Skin care and skin cancer prevention
An annual evaluation of the skin is necessary to analyze the detection of skin cancer or lesions that may lead to it.
Albinism in animals
The albino disorder also occurs in wildlife. Some specimens present an appearance that does not correspond to the members of their species; they are albino animals.
In animals it also occurs as a hereditary disorder that consists of the absence of melanin in the skin and eyes. The lack of pigmentation produces the following consequences in the fauna.
- Pink or red eyes
This when it is a complete albinism or blue, brown or green (oculocutaneous albinism 2, 3 and 4).
- Greyish or pinkish skin
It is due to the bloodstream that is seen through the colorless dermis.
- Decreased visual ability.
- Hearing problems.
However, the consequences for albino animals are not only limited to physical appearance or decreased acuity of the senses. Since in nature these animals lack camouflage to hide from predators. In fact, light colors make them more visible and prone to attack. For this reason, the hope of albino animals in the wild is low.
This disorder can affect any animal, although it is seen in domestic animals such as mice, dogs, cats and rabbits.