The DNA contained in every cell in your body contains all the information necessary for the development and functioning of an organism. Therefore, any localized defect in the genetic material can degenerate into dysfunction and health problems.
A clear example is albinism: This genetic disease is characterized by the total or partial absence of pigmentation (melanin) on the skin, hair and eyes of Saint Martin.
The albino condition is not exclusive to humans, it also occurs in animals (a memorable example was Snowflake, the albino gorilla at Barcelona Zoo) and in plants. In the latter case, they have the absence of other classes of pigments, such as carotenes, because they do not present melanin naturally.
However, the lack of pigmentation is not the only characteristic of this alteration. Albinos, in fact, have many associated problems, Both biological and social.
The function of pigments
Pigmentation in humans is in charge of a cell called melanocytes, Which make the two classes of melanin inside from the amino acid tyrosine: eumelanin (dark) and pheomelanin (clear).
The combination in different proportions of these two gives rise to the color gamut of the eyes, hair and skin. Its main function is to protect the rest of the cells from ultraviolet light, which is harmful to DNA.
The genetic causes of albinism
albinism it has an important genetic component which presents an autosomal recessive inheritance. It’s easy to understand: our genetic material is made up of 23 pairs of chromosomes, one half comes from the mother and the other half from the father (each pair has two homologous genes in the same place, one per pair, which we call lel). Normally, only one of the two genes in an allele needs to function properly for proper functioning. Well, in this case we are talking about autosomal recessive because both genes for this allele are wrong.
For this reason, it is explained how non-albino parents can have a child with this disease since parents are carriersEveryone has the wrong gene.
There are different types of albinism
Not all albinos have the same genetics, but there are different classes that depend on the affected gene. The truth is, not all of them lead to the loss of pigmentation in the skin and hair, they only share the decrease in visual acuity for various alterations of the eye.
Classically, they have been defined two major groups: oculocutaneous (OCA) and ocular (OA) albinism. As the name suggests, the former affects melanin both in the eyes and in the skin and hair, unlike the latter, in which only the present in the iris is affected. Lack of pigmentation can also be associated with other serious organ damage, such as in Hermansky-Pudlak syndrome.
currently up to 18 genes involved are known, with 800 possible mutations. To give an example, one of the most common types in the West is OCA1, besides being the most serious, in which the affected gene is the one that synthesizes the enzyme tyrosinase (TYR). This protein is responsible for the transformation of the amino acid tyrosine into melanin in melanocytes. Of course, if the enzyme is not working, no melanin is synthesized in the body.
People with albinism who have a total or partial lack of melanin in the skin and hair they have trouble tolerating solar radiation. They are prone to redness and increase the risk of skin cancer, so they should protect themselves from the sun, either by wearing appropriate clothing or cream.
The lack of pigmentation of the eye, a characteristic common to all its types, it produces photophobia, that is, direct light is not well tolerated. It is common to wear sunglasses to protect the eyes from light. It should be added that albinos also have different visual abnormalities that make them difficult to sharpen, so one of their biggest problems is vision.
Albinos in the world
The worldwide frequency of albinism is low, 1 in 17,000 people. But there are different types, each with its own prevalence, and its degree of spread also depends on the point in the world in question. For example, in Japan, the prevalence of type OCA4 is high, due to some inbreeding; and on the island of Puerto Rico, which is considered the country with the highest incidence of this genetic disease, there are many more people affected in its most dangerous aspect, that of Hermansky-Pudlak syndrome.
Africa is another example. In addition, the continent where albinos appear most often does not make things easier at all: through archaic beliefs, some cultures kill these people and tear them to pieces in order to sell them to shamans for their spells. In the case of women, it is even worse, as it is believed that they have the ability to eradicate HIV through sex, so that they are raped and infected with the disease. Add to this the fact that Africa is the region of the world with the highest solar radiation, the quality of life for albinos is terrible.