Albinism; heterogeneous genetic disorder
Albinism is a heterogeneous genetic disorder, caused by mutations in different genes, which results in a reduction or total absence of melanin pigment in the eyes, skin and hair.
It occurs in humans and other animals.
It can also occur in plants, where other compounds, such as carotenes, are missing. It is inherited; it appears with the combination of both parents carrying the recessive gene.
In non-albino individuals, melanocytes transform the amino acid tyrosine into the substance known as melanin.
Melanin is distributed throughout the body to give color and protection to the skin, hair and iris of the eye.
When the body is unable to produce this substance or to distribute it, hypopigmentation, known as albinism, occurs. Melanin is synthesized after a series of enzymatic reactions (metabolic pathway) by which the above mentioned amino acid is transformed into melanin by the action of the enzyme tyrosinase.
Albino individuals have this metabolic pathway interrupted because their tyrosinase enzyme has no or very little activity (so little that it is insufficient), so the transformation does not occur and these individuals will not have pigmentation.
There are different types of albinism and some may be blond or just have light eyes but no blond hair.
It is therefore incorrect to conclude that an albino person has all the characteristics in one.
Today, this genetic condition is widespread in the world. One in every 17,000 people has some form of albinism.
