ALBINISM

Albinism is an inherited genetic disorder characterized by the partial or complete absence of pigment in the skin, hair, and eyes due to a disorder in the cells that produce melanin.


The name comes from the Latin word albus, which means white. Melanin is a black or brown pigment produced by enzymatic oxidation of tyrosine, which is contained in a large number of plant and animal species, as well as in humans. In animals and humans, melanin is produced in melanocyte cells in the skin, eyes and hair and affects their color. In albinism, the number of melanocytes is normal, but melanin synthesis is impaired. Absence of chlorophyll formation in plant species is also called albinism.
Albinism is equally prevalent in men and women. It is inherited through recessive genes, which means that both parents must have the disorder (which may not be visible) in order for it to be passed on to the child. If only one parent has this gene, it is very rare for a child to inherit it, but it is still possible. Albinism is common in children from marriages between close relatives. Physical symptoms of the disease are a very light complexion, light or white hair in childhood, very light eyes, which can even be reddish or pink in color.

History of albinism


The oldest records of albinism were found in Rome and Germany. The first people to study this rare genetic disorder were Aulus Gellius and Plinius Secundus the Elder, various information about this was found in their writings. Even in 1904, cases of albinism in animals were discovered. But it was only in 1908 that Archibald Garrodje officially recognized albinism as a disease and became known as the father of albinism. He described the disease as an inborn error in metabolism.
The first extensive scientific data on albinism, with an extensive monograph including texts, photographs, drawings and an atlas of persons and families with albinism from all parts of the world, was written by Carl Pearson in 1911. It is stated here that people who lived around 400 BC described people who had albinism, then Pliny, a Roman naturalist, described eye and hair color, as well as photophobia in people with albinism.
The exploitation of various parts of the world by European explorers in the 16th and 17th centuries made possible the more frequent study of individuals with light skin and hair in northern Africa, the Middle East, Ceylon, Brazil, and New Mexico. Advances in scientific medical literature in the 18th and 19th centuries provided expert descriptions and symptoms of albinism. Further development of science at the beginning of the 20th century made it possible to understand the recessive genetic nature of albinism.
All these years of research have allowed us to understand the complex syndrome of albinism today.

Types of albinism

There are several types of albinism, depending on how they are inherited. The most common types are tyrosinase positive and tyrosinase negative. Depending on the degree of tyrosinase activity, several subtypes are distinguished. Other known disorders that have albinism as a symptom are Chediak-Higashi syndrome, Hermansky-Pudlak syndrome, and Waardenburg syndrome.
People who do not have the enzyme tyrosinase develop a picture called tyrosinase negative albinism, and people in whom the defect occurs in the late stages of melanin synthesis or in the storage or transfer of melanin develop a picture of tyrosinase positive albinism.




Tyrosinase positive albinism

It was first described among the Zuni Indians of New Mexico in individuals with a defect on chromosome 15q11-q12. It is the most common form of albinism, 1:15,000 in blacks and half of that in whites. At birth, the skin is completely white, and later it can turn from pink to cream, especially in blacks. Patients have tan hair and blue to tan eyes. Numerous freckles and melanocytic moles can be seen on the skin. Vision problems are not particularly pronounced.

The group of tyrosinase positive albinism also includes two syndromes:
• Hermansky - Pudlak syndrome
• Chediak - Higashi syndrome

1. Hermansky - Pudlak syndrome is an autosomal recessive disease. Although most studied in Puerto Ricans, it can be found anywhere in the world. It was first described in 1959. two Czechs. Patients have white or "cream" skin, with numerous freckles and melanocytic moles, their hair is "cream" to light brown, and their eye color varies from blue to light brown. They also very often have problems with their eyes - most often it is a high sensitivity to light, they have reduced visual acuity, and less often nystagmus (uncontrolled eye movements) and strabismus. People suffering from this syndrome often suffer from blood clotting disorders; they are prone to bleeding and bruising. Bleeding can also occur in the intestines, and these patients have bloody diarrhea and abdominal pain. Therefore, they must not take aspirin. Interestingly, routine blood coagulation tests may be normal - such as platelet count, prothrombin time, and partial thromboplastin time. Bleeding time is usually prolonged, although it can also be normal.

2. Chediak-Higashi syndrome is also an autosomal recessive genodermatosis. Caucasians with this syndrome have completely white skin, while blacks have a grayish tone. The hair has a "metallic" color. These patients may have difficulties in growth and development as well as a great tendency to frequent infections - especially of the skin and oral cavity. About 80% of patients develop a picture like lymphohistiocytic lymphoma with changes in the liver, spleen and lymph nodes with regular occurrence of anemia, bleeding and serious infections that can lead to death.

Tyrosinase negative albinism

Is another common type of albinism, also an autosomal recessive disease. Caused by gene mutation on chromosome 11 segment q14-q21 There are several subtypes of this type of albinism:

• Type I-A-only in this type there is a complete absence of melanin. In all others, it can be found in smaller traces. The most common symptoms are completely white skin color, frequent sunburns, light blue hair, pale-light blue eyes, reddish pupils, photophobia, strabismus, impaired vision

• Type I-B- melanin production is greatly reduced, but small amounts are still present. The hair of people with this type of albinism has a yellowish-reddish color, and the other symptoms are the same as in the previous type, only less pronounced

• Type I-MB- minimal production of melanin

• Type I-TS (Temperature-sensitive melanin production) - in this type, melanin production is dependent on body temperature. Normal body temperature prevents the production of melanin, but on the extremities, where the temperature is slightly lower, pigmentation is present

Waardenburg syndrome

This syndrome is an inherited genetic disorder that can cause hearing loss or partial albinism, i.e. changes in skin and hair pigmentation. It occurs equally in men and women and in all ethnic groups of people. It was found that one person with this syndrome occurs in 42,000 people. The syndrome was named after a Dutch doctor named Petrus Johannes Waardenburg, who first noticed that people with unusual eye color had certain hearing problems. After many years of study, he concluded that one of the main characteristics of people with this syndrome is the different color of their eyes. One eye is usually brown and the other blue. Also, these people usually have light blond or white hair, especially children. There are at least 4 types of this syndrome, all of them are autosomal recessive diseases, that is, they are inherited from both parents.

Albinism in humans

Albinism is a rare genetic disease. According to research, it is most widespread in Africa. It is believed that one person in 17,000 has some form of albinism, while every seventieth person carries this gene. In second place is America, where one person in 20,000 has some form of albinism. It occurs equally in men and women and in all races. Children with albinism usually have parents who do not have symptoms, have normal skin, hair and eye color, but they only carry this gene.
This disorder is hereditary and cannot be acquired in any other way. Children whose parents have the same disorder are at risk of albinism, children whose parents do not have albinism, but only carry the gene, people who have cases of albinism in their immediate family.
There is no cure for albinism. Treatment aims to reduce symptoms. Only in rarer forms of albinism, which result in impaired vision or other health problems, treatment is necessary. Preventive treatment refers to the protection of eyes and skin, especially from solar radiation. No way to prevent albinism has been discovered. People who have the most common forms of albinism live a completely normal life. Only people who have a very rare type of this disorder, namely Hermansky-Pudlak syndrome, which causes significant complications, must have appropriate treatment. There is an increased risk of skin cancer, but with proper care it can be prevented. People who have albinism, but do not carry the gene, can have children who do not have the disease.
People with albinism often have problems in social life. Throughout history, people with this disorder have often been shunned by society due to their strange physical appearance, in some countries they were thought to possess supernatural powers, to be able to predict the future or heal the sick. In recent years in Africa, especially in Tanzania and Burundi, albino people have been killed for their body parts. Witch doctors believe that if body parts of albinos are added to certain drinks, a person can be cured or enriched. Many people believe that albinos are cursed and their condition is contagious. That is why it is necessary to educate people about this rare genetic disorder.
There are various organizations around the world that help albinos learn about their disease and advise them on treatment. There are also organizations that help parents who have children with albinism

Albinism in animals

Albinism in animals is also hereditary. It occurs in all types of animals that produce melanin. Observations in mammals, birds, reptiles, amphibians, fish, molluscs and insects. Almost all domestic animals have some form of albinism. Interestingly, Siamese cats are also albino. Mice, rabbits and hamsters used in laboratories are most often albino animals. They are considered to be easier to work with, most likely because they have impaired eyesight. Not all albino animals are completely white, because some animals produce smaller or larger amounts of melanin, which forms the pigment in the animal's skin or fur.

Not all white animals have albinism. The easiest way to distinguish between animals is the eyes. Melanin affects the development of the animal's eyes and vision. Without brown-black or red-yellow pigment, the eyes of albino animals are pink or light blue. Melanin in mammals and other animals has a double role: protection from the sun, i.e. harmful solar radiation, and develops vision, i.e. it affects the development of certain parts of the eyes such as the eye muscles, optic nerves and pupils.

Scientists have also investigated how animal life unfolds in the wild. Animals must be able to provide themselves with food, offspring, to perceive danger and to avoid enemies. Research has shown how white albino fur or a lack of camouflage affects animals as potential prey. Sometimes, albino animals are easier to spot because of their white color and easier to become prey than other animals. On the other hand, in some cases, predators did not recognize them as food. In studies where there were many opportunities to hide, predators took albino animals at the same rate as those with normal color.

In many species of birds such as penguins and ravens, research has shown that if they have albinism, these animals have a harder time finding a partner for mating. These animals are constantly rejected by other animals of the same species, probably due to the lack of fur or certain distinctive patterns.

Even if witchcraft and pagan beliefs still exist in some parts of the world, the situation is more suitable for albino people. Laws are stricter and people in Tanzania and Burundi are now being held accountable for their actions. But despite that, the Albino World Alliance (AWA - Albinism World Alliance) was founded in 1992.
The Albino World Alliance is engaged in supporting albino people in many countries. It was founded in 1992 by representatives from Australia, Canada, Tanzania, Great Britain, and the United States. Over the years, it expanded to include support groups