The type and amount of melanin produced by the human body determines the color of skin, hair and eyes. Most people with albinism are sensitive to sun exposure and is at increased risk of developing skin cancer.
Parents should be surrounded by love and attention a child with albinism and protect against attacks peers. Albinos are subject to stress, depression and psychosis.
Causes of albinism
Albinism occurs in humans due to lack of, or blockade of the enzyme tyrosinase. It is extremely important for melanin production (the name comes from the Greek word "melanos", which in Russian means "black"). Skin color is determined by the amount of melanin in it. What it is, the darker the skin. In those cases, when problems with the generation of tyrosinase is not observed, the cause of albinism is considered to be a mutation in the genes.
Albinism is inherited from parents. He appears in a child if both parents are carriers of the defective gene. When the defective gene is present in only one parent, albinism does not develop in children, but the body is still a mutated gene that can be passed to the next generation. This whole process is called autosomal recessive inheritance.
features of the disease
Albinism is a congenital pathology presented. This disease occurs with equal frequency in boys, girls.
Its appearance is triggered by lack of blockade of the tyrosinase enzyme. Tyrosinase regulates the synthesis of a special pigment - melanin in the parts of the body such as the dermis, the hair, the iris of the eye. The pathology can be complete or partial.
Usually albinos are not much different from ordinary people (in development), but not excluded, and cases when such people have observed pathology:
- mental retardation;
- violation of visual acuity.
What is most interesting, the disease is considered to be found on all continents, in different ethnic groups. It belongs to the hereditary pathology.
The first signs of albinism, photos
From birth, people-albinos have little or no pigment in the skin, eyes and hair (okulokutanny albinism) or only in the eyes (ocular albinism). The degree of pigmentation varies in each case. Some people gain a little pigmentation of hair or eyes with age. Others have formed color painted freckles on the skin. Individuals with a complete lack of melanin called albinos. Albinoidy - people with a very small amount of melanin. But it is impossible not to pay attention to common among albinos eye problems and skin.
- Skin problems. Dark pigment Melanin helps protect the skin from ultraviolet radiation from sunlight. Albinos lack of pigment, so their skin is very sensitive to direct sunlight. You must take precautions to avoid skin burns, namely to use sunscreen, be sure to wear hats and special clothing.
- Vision problems. They are due to abnormal development of the retina (fovea hypoplasia) and abnormal system the neural connection between the eye and the brain: the complete crossing of the optic nerves, while OK - partial. When albinism can be detected: nystagmus and transparency of the iris, as well as reduced visual acuity, strabismus, impaired binocular vision, increased sensitivity to light exposure - photophobia.
People with albinism have pale enough, they have a very blond hair and discolored eyes. Sometimes their eyes become red or even purple color that depends on the amount of pigment. This is due to the fact that the iris is almost no color and eyes appear red or pink due to the translucent through iris vessels inside the eye. However, people with albinism otherwise as healthy as the rest of the population.
How is the diagnosis?
Process diagnosis albinism includes the following activities:
- External examination of the patient;
- The study of pigmentation changes;
- Conduct a detailed eye examination;
- Collecting a family history.
In a survey conducted necessary consultations ophthalmologist. This helps to identify changes such as strabismus, photophobia, nystagmus (involuntary eye movement). If albinism is always a defeat of both eyes. If the examination reveals changes only in one eye, you should consider other options for diagnosis.
There is a method of determining the presence of a defective gene causing albinism. This analysis reveals some form of the disease before birth. Chorionic villus study allows us to identify signs of mutation of genes in the fetus is still in the fifth week of pregnancy.
Upon detection of albinism specific treatment to date, there have been developed only preventive measures that will improve the patient's quality of life. To preserve the existing level of required eye protection from sunlight - this is achieved by wearing special sunglasses or contact lenses.
Appearance in bright sunlight to be avoided, or to protect the skin with special creams and lotions. If you adhere to these recommendations, in general albinism favorable prognosis - patients can live a long and full life. It is necessary to regularly consult a dermatologist and an ophthalmologist - to prevent complications, such as skin cancer or retinal detachment.
Help a child or family member with albinism may be teaching them the rules of self-help, namely:
- required the use of a sunscreen with a sun protection factor of at least 30, and as of UVA, UVB and on the beams;
- Avoid exposure to the sun during the peak heat (from 11 hours to 16 hours);
- you must use the means that increase sharpness of vision (glasses, special magnifiers, monoculars);
- Clothing should be closed - shirts with sleeves, long skirts or dresses, pants, hats with brims, sunglasses;
- necessary to protect the eyes from ultraviolet radiation, for example, wearing dark glasses or transitional lenses that darken in bright light.
There is only one way to prevent the development of mountaineering. It consists in carrying out a genetic study couples planning a pregnancy. Modern methods make it easy to detect the presence of defective genes and assess the risk of having a child with this pathology.
In humans, albinism is inherited as an autosomal recessive trait
In humans, albinism is inherited as an autosomal recessive trait, and color blindness as a sign, linked X-chromosome. Determine the genotypes of the parents, as well as the possible genotypes and phenotypes of the offspring and their percentage of the marriage heterozygous for the first sign of a healthy woman who is not a carrier of the gene of color blindness, and men - and color-blind albino. What are the laws of inheritance will be shown in this case?
- A - normal pigmentation
- and - an albino
- X (B) - normal eyesight
- X (c) - daltonism
According to condition the mother is heterozygous for the gene of albinism and having normal vision - ACX (B) X (V)
- Male albino color blind, and ACX (c) Y
- ♂aaH (a) Y x ♀AaH (B) X (V) = C X (C) Y - boy normal pigmentation, normal vision, ACX (B) Y - boy albino normal vision, ACX (B) X (a) - Girl normal pigmentation, normal vision, ACX (B) X (a) - Girl albino normal vision.
Manifest the laws of inheritance sex-linked and splitting.