Definition and classification
Albinism represents a group of genetic anomalies inherent in the synthesis of melanin; the term " albinism " comes from the Latin " albus ", which means "white".
- " Total albinism ": a rather rare pathological manifestation, characterized by white or straw-colored hair, very white skin and blue or gray eyes.
- " Partial albinism ": more frequent dysfunction, which affects only certain parts of the body, such as a circumscribed area of the skin, a tuft of hair or the eyes.
- " Ocular cutaneous albinism ": the pathology is also generalized in hair, skin and eyes, with an incidence frequency of 1: 35, 000. In this case, melanin is no longer synthesized.
- " Ocular albinism ": the melanin pigment is absent in the retina, consequently the subjects affected by this type of albinism have a lower number of diopters. It affects one newborn every 15, 000.
Each of these pathologies has a given incidence in the population; to give a statistical approximation, one person every 17, 000 manifests a typology of albinism.
Considering that this serious disease affects all ethnic groups and all animal species, albinism represents one of the most widespread pathological manifestations of genetic transmission, not only in the animal kingdom, but also in the vegetable one (considering that some cases have occurred of albinism also in the flowers, in the petals, in the fruits and in the leaves).
Causes
Considering that albinism is a genetic disease, the triggering cause coincides with an alteration of the genes involved in the production of melanin; so far 11 genes involved in this delicate mechanism have been specified, and appear to be associated with the tyrosinase enzyme. In order to produce an insufficient amount of melanin, or even to prevent the production of the pigment itself, it is sufficient that only one of these genes has a defect. Strictly speaking, it is understandable how the correct functioning of tyrosinase is indispensable for the production of melanin pigment: the enzyme is implicated above all in oculo-cutaneous albinism.
If both parents are affected by albinism, the generated offspring will also manifest this pathology; despite this, the parents of most albino children exhibit regular pigmentation of the skin, eyes and hair, and do not have a family history of albinism. In the latter case, a point mutation of the tyrosinase enzyme occurred in the offspring, so that the organism no longer synthesizes melanin.
Physical effects
To learn more: Albinism symptoms
Only those subjects who have very white skin, white hair and red eyes are mistakenly considered albinos: in reality, although these signs favor the identification of people, it should be emphasized that the growth and functioning of the skin and hair are normal; what changes is only the color, which fades from white to almost normal coloring.
One of the most serious consequences for albino people is represented by the damage they can suffer as a result of exposure to the sun ( heliophobia) : the skin, not being pigmented (or only partially), lacks natural protection. In healthy subjects, sun exposure enhances melanin production: the acquired tan acts as a "natural sun filter", protecting the skin from light radiation. This does not occur in albino people: since melanin is not produced, the skin is not protected, and the risk of sunburn increases, enhancing the predisposition to skin tumors.
The consequences deriving from the tyrosinase mutation also affect the eyes: during embryonic development and in the post-natal period, the right amount of melanin is not produced, or not produced at all, which causes damage to the eye and causes changes in the iris, in the retina and in the optic nerves. Nystagmus (involuntary oscillation of the eyes, sometimes also associated with a slight movement of the head), strabismus and vision deficit, are possible effects derived from the albino pathology: their entity is proportional to the amount of melanin produced during the development of the eye.
In rare types of albinism, also hearing and blood clotting may present some disorders.
Psychological effects
People with albinism often have the perception of feeling sick, discriminated and different from others: the social and psychological problems arising from this pathology are very complicated. Suffice it to say that albino children often tend to isolate themselves from others: forced to continually respond to embarrassing questions about their pathology, they are subjected to a critical psychological stress. Even if the growth and physical development of the child are not compromised by albinism, the psychological repercussions of the disease should certainly not be underestimated. Among the most used natural remedies in the presence of brittle nails we recall the horsetail
