albinism, what is the albinism, which are the causes, which are the symptoms, the possible complications, who consult

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Albinism

This term gathers a whole of genetic diseases characterized by a depigmentation of the eyes, skin, hair and superficial body growths. 20.000 people in France would be concerned.

What is it?

Albinism, of genetic cause, can be divided into two main categories:
- oculo-cutaneous albinism: it includes/understands a whole of genetic diseases (10 different forms) in which an anomaly of the synthesis of melanine key either the skin, or the eyes, or both. The disorders are more or less severe according to the form of the disease.

- ocular albinism: this form of albinism is characterized by a nystagmus (movementsof oscillation involuntary and jerked ocular sphere) congenital, a depigmentation of the iris and retina and a reduction in l’ vision, often accompanied by a less powerful binocular vision and a possible strabism. The people reached of this type of albinism are known as photophobes, i.e. they do not support the light and must thus avoid it permanently.

Which are the causes?

Heredity: All the forms of albinism are genetic. Oculo-cutaneous albinism, whatever the form, is transmitted on a recessive autosomal mode, which means that the disease reached as much the girls as the boys and it appears only when we are carrying two transferred genes of the disease. Each of the two parents must obligatorily be carrying gene transferred to transmit the disease.
Each of the two parents must obligatorily be carrying gene transferred to transmit the disease. They are called healthy carriers since they have sick gene but are not to it themselves. Two healthy carriers which make a child together have a chance on four to have an ill child and this risk is the same one with each pregnancy. The most widespread form of ocular albinism is also transmitted on a recessive mode, only the genetic anomaly is carried by a sexual chromosome, X chromosome, that the woman have in double specimen.
Thus, in this case, a mother is carrying healthy sick gene and has a chance on two to have a sick boy. If the mother gives birth to a girl, the latter has a chance on two to have sick gene and thus to be carrying healthy.
Depigmentation: during albinisms, the full number of melanocytes (cells responsible for the pigmentation) is normal. The anomaly relates to an enzyme essential to the production of the melanine, tyrosinase. The absence of melanine in the melanocytes involves quite particular morphogic characteristics (cf symptoms).

Which are the symptoms?

The people reached of oculo-cutaneous albinism present a quite particular type:
- Grey hair or fair very pale
- Iris of the gray or blue eyes.
- Pupil with more or less visible red reflection.
- Very clear skin.

According to the form of the disease, a patient will present one or more these symptoms, more or less marked. In all the cases, the patients see very badly by far (often in lower part of 4 dioptres). This anomaly is badly corrected by the wearing of glasses.

Which are the possible complications?

Normally, the melanine day a protective role with respect to UV solar. In the absence of this pigment, the skin is dangerously more sensitive to the sun the consequences of exposures repeated to the sun can go from the simple sunstroke to the cancer of the skin. The eyes must also be protected from solar light. The albino, people reached of albinism, must thus constantly flee and protect himself from the sun.

Who to consult?
A dermatologist and an ophtalmologist, who must work concert to prevent
the complications.

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