When a person is born with a mutation, a change in the genes that leads to some alteration or disability in his life, we might think that the genetic condition he acquires from birth will have the same consequences, wherever he was born in this world. The reality, however, is unfortunately different. There are regions of the Earth, entire continents, where everything is more difficult and complicated. Africa is the paradigmatic example.
To be a person with albinism in Europe or in Africa is not the same. Not at all.
Albinism is one of the so-called rare diseases, of which we know thousands, although each one affects few or very few people. In Europe and North America it is estimated that about 1 in 17000 people is born with one of the 20 known types of albinism.
Why are there more people with albinism in Africa than in Europe?
To answer this question I must explain what happens to people with albinism. Albinism has a significant but variable visual impairment that is common to all known types of this genetic condition. Additionally, many of the types of albinism show failures in the production of pigment, melanin, hence the appearance so characteristic of many people with albinism. Lack of pigment in Europe can even go unnoticed in Scandinavian countries. But in Africa, the lack of pigmentation stands out. And its consequences are also different.
The lack of protection against solar radiation causes burns and lesions on the skin, which, if not treated properly (as it usually happens in Europe) can malign and end in skin cancer, which unfortunately and unnecessarily ends the lives of many people with albinism in Africa prematurely. Its uniqueness was historically a source of rejection. Babies with albinism usually disappeared after birth. But recently everything changed for the worse. People with albinism in Africa became the object of a horrendous interest, animated by magic and ignorant beliefs, being persecuted, kidnapped, mutilated and killed in order to trade in their body parts, which supposedly grant good fortune to their holders.
The response in many cases of the community of people with albinism has been to take refuge and protect themselves together, which inevitably leads to families being established between people with albinism
Given that in Africa the majority of these people are of the same kind of albinism, then all their children will also present albinism, artificially increasing the proportion of people with albinism that should be in the population.
Most frequent types of albinism
In Europe the most common type of albinism is OCA1 (oculocutaneous albinism type 1), caused by mutations in the TYR gene. On the contrary, in Africa the most frequent albinism is OCA2 (oculocutaneous albinism type 2), produced by mutations in a gene with the same name. Mutations appear, randomly, constantly and affect all our genes. Sometimes, a mutation appears for the first time in a person in a community, more or less separate from the rest, and then, it is transmitted from parents to children and spreads rapidly among the members of the same. We then speak of the so-called founding effect. In Africa, this founding effect is responsible for the fact that many people with albinism are not only OCA2 but also carry the same mutation.
Researcher at the Consejo Superior de Investigaciones Científicas (CSIC) and the Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), at the Instituto de Salud Carlos III (ISCIII), at the Centro Nacional de Biotecnología (CNB), Madrid.