Albinism: Is it a tanning condition or something worse?
A peek into albinism and better understand what causes the condition.
Written by Harini G
What is Albinism?
Albinism is a group of genetic conditions in which a person has no or very little melanin pigment in their skin, hair and eyes. Albinism occurs in all racial and ethnic groups throughout the world. In Australia, about one in 17,000 people have some type of albinism. It is important for people with albinism to protect their skin and eyes from the sun, and have their eyes checked regularly.
How many types of albinism are there & how to differentiate them?
There are two main types of albinism:
ocular albinism, in which the eyes are affected, but the color of the hair and skin is fairly normal
oculocutaneous albinism, in which the hair, skin and eyes are all affected
- OCA type 1: Individuals tend to have milky skin, white hair, and blue eyes. With age, some individuals’ skin and hair may darken.
- OCA type 2: Less severe than type 1, this occurs most often in sub-Saharan Africans, African-Americans, and Native Americans.
- OCA type 3: Vision problems are normally milder than in other types. This mostly affects black South Africans.
- OCA type 4: This is most common among East Asian populations. It appears similar to type 2.
There are also some extremely rare conditions where people have albinism and other health problems. Examples are Hermansky Pudlak syndrome, Chediak Higashi syndrome and Griscelli syndrome.
Signs and symptoms of albinism:
Some children with albinism are born with pinkish-white skin and white hair. Their eyes are usually light grey, blue or hazel, although they can look pink in the light.
People with albinism usually have poor vision. Glasses can help, but some have poor vision even with glasses. Several eye conditions can affect people with albinism including nystagmus, which is horizontal back and forth movement of the eyes, and photophobia, which is sensitivity to bright light and glare.
What causes albinism?
Albinism results from the mutation of one of several genes. One in 70 people are thought to carry the gene for albinism. The genes in question are responsible for various aspects of the production of melanin by melanocytes in the skin and eyes.
Most commonly, the mutations interfere with the enzyme tyrosinase (tyrosine 3-monooxygenase). This enzyme synthesizes melanin from the amino acid tyrosine. Depending on the mutation, melanin production can either be slowed or completely stopped. Regardless of the amount of interference with melanin production, there are always problems with the visual system. This is because melanin plays a vital role in the development of the retina and the optic nerve pathways from the eye to the brain.
Can this condition be inherited?
Most types of albinism are inherited in an autosomal recessive inheritance pattern. The exception is X-linked ocular albinism. This is passed on in an X-linked inheritance pattern.
Autosomal recessive inheritance:
With autosomal recessive inheritance, an individual must receive faulty copies of a gene from the mother and father to develop albinism.
The parent who carries the gene often does not show symptoms.
If both parents carry the gene but have no symptoms, there is a 1 in 4 chance that their offspring will have albinism.
There is a 1 in 2 chance that the offspring will become a carrier.
They will have the gene but not have any symptoms.
An estimated 1 in 70 people carry the genes associated with albinism but are not affected by the mutations.
X-linked inheritance:
X-linked recessive conditions mainly affect males.
Because females carry two X chromosomes, if one gene damaged, the other can often make up the shortfall.
Females can still carry and pass on the gene.
Men, however, have one X and one Y chromosome. This means that any albino mutations in their singular X chromosome will generate the condition.
If the mother has an X-linked mutation, each daughter will have a 1 in 2 chance of becoming a carrier and each son will have a 1 in 2 chance of developing albinism.
Treatment:
As the disease is genetic, there are no cures at the moment.
However there are treatments that focus on minimizing the symptoms and watching for changes.
Bibliography:
3. https://www.healthdirect.gov.au/albinism
