(Hypopigmentation; Oculocutaneous Albinism; Ocular Albinism)
Albinism – Definition
Albinism refers to a group of rare inherited disorders that are present from birth. Albinism affects the amount of pigment found in the skin, hair, and eyes. People with albinism usually have little to no pigment in their eyes, skin, and hair, but the degree of pigment loss can be quite variable. There are four types of Albinism:
- Oculocutaneous albinism
- Type 1—complete absence of pigment. Skin, hair, and eyes lack all pigment from birth. Freckles or moles will not appear at any time during their lifetimes. This group is divided into several subtypes depending on associated characteristics.
- Type 2—decreased pigment, but may still have freckles and moles. This form of albinism is more common among persons of African descent. This form may be associated with such minimal pigment loss that it is evident only by comparison with other non-affected family members.
- Both Type 1 and Type 2 albinism are usually associated with visual problems including nystagmus (abnormal jumping movements of the eyes) and decreased visual acuity, which is frequently not fully improved with glasses or contact lenses.
- Type 3—reddish brown skin, reddish hair and hazel or brown eyes, generally black South Africans.
- Type 4––similar to type 2, predominantly in Japanese persons.
- X-Linked albinism––vision problems without changes in skin or hair.
- Hermansky-Pudlak––in addition to albinism, persons also have lung, bowel, and bleeding problems.
- Chediak-Higashi––in addition to albinism, persons also have immune problems with defects in white blood cells.
Albinism – Causes
Albinism occurs as a result of altered genes. In most cases these genes are inherited from parents. It may be autosomal recessive or X-linked.
Autosomal recessive inheritance accounts for the vast majority of cases. This means that both parents carry one copy of an abnormal gene but do not have symptoms or signs of albinism. Children become affected only if they inherit one affected gene from each parent. In this form of inheritance, each child has a one-in-four chance of inheriting the condition. The abnormal gene reduces (or completely eliminates) the body’s ability to make a pigment called melanin. There are several dozen different genetic subtypes of albinism. Individuals can have full or partial absence of this pigment which will affect the color of eyes, hair, and skin.
The chance of inheriting an X-linked altered gene will vary by the sex of the baby. Females have two X chromosomes while males have one X and one Y. If only one parent is affected the daughter will have one affected X chromosome and one normal X chromosome. The daughter will be a carrier but not have signs or symptoms herself. The son however only has on X chromosome. If the X chromosone that the son inherits is affected than the child will have albinism.
Albinism – Risk Factors
Albinism is a hereditary disorder. Therefore, people at risk of inheriting albinism are:
- Children of parents who have albinism
- Children of parents who do not have albinism, but carry the altered genes that cause this disorder
- A positive family history for albinism in a sibling or other relative
Albinism is rare. In the United States, about 1 in 17,000 individuals overall has some form of albinism. All races are affected, though Type 1 occurs predominantly in whites and Type 2 in blacks. Most children with albinism are born to parents with normal hair and skin color for their ethnic background.
Albinism – Symptoms
The symptoms of albinism depend on the specific type of albinism one has. Some types affect the skin, hair, and eyes. Other types affect only the eyes or only the skin.
Symptoms may include:
- Eye problems, such as:
- Strabismus or crossed or wandering eye
- Poor vision (which usually cannot be fully corrected with glasses or contacts)
- In some cases, functional blindness
- Nystagmus or irregular, rapid eye movement.
- Amblyopia or “lazy” eye.
- Photophobia–sensitivity to bright lights or glare
- Skin problems, including:
- Little or no pigmentation (resulting in extremely light or white skin)
- Patches of low pigmentation (resulting in patches of extremely light or white skin)
- Extreme sensitivity to sunburn
- Very high susceptibility to skin cancer
- Hair problems, including:
- White hair
- Portions of the hair (often the forelock) being white
- Certain rare types of albinism, such as Hermansky-Pudlak syndrome, can cause other symptoms, including:
- Bleeding disorders
- Lung disease
- Bowel disease
- Hearing loss
- Nervous system disorders
- The common forms, Type 1 and 2 albinism are not associated with these more serious symptoms.
Albinism – Diagnosis
In many types of albinism, the disorder can be diagnosed by observation of major or total absence of pigmentation of the hair, skin, and eyes. If needed, chemical testing of hair can provide an easy confirmation of the diagnosis. Because most types of albinism affect the eyes, certain eye tests (including an electroretinogram) are used to help confirm the diagnosis. For some types of albinism, DNA genetic testing can also be used to confirm the diagnosis.
While albinism is always apparent at birth, it may be so mild that affected persons are unaware of their diagnosis unless abnormal eye movements or vision develop.
Albinism – Treatment
There is no cure for albinism. Treatment is aimed at preventing or limiting symptoms. In some cases, specific treatment for certain symptoms is needed.
Albinism – Preventive Treatment
Preventive treatment may include:
- Protect the skin:
- Sunburn and skin cancer risks can be reduced by avoiding the sun as much as possible
- Wear sunscreen with high SPF 30 or higher with UVA and UVB protection
- Cover as much skin as possible with clothing when exposed to the sun
- Protect the eyes:
- Wear sunglasses with UV protection whenever exposed to the sun
- Sunglasses (UV protected) may relieve photophobia
Albinism – Specific Treatment of Symptoms
Specific treatment of symptoms for albinism may include:
- For eyes:
- Glasses, contacts, and/or optical aids to help improve vision
- Surgery to correct certain eye problems, including crossed eyes or “lazy” eye
- Visual aids (in the classroom) to help children with albinism
- For skin:
- Surgery to treat and/or remove skin cancer, if necessary
These treatments may be of special importance in Africa where the World Health Organization estimates that thousands of affected individuals live without access to important medical and preventive care.
Studies in mice with genetic forms of albinism suggest that gene transfer may prevent visual disturbances. Whether these results may someday be applied to people with ocular albinism remains to be seen.
Albinism – Prognosis
- People with the most common forms of Type 1 and Type 2 albinism and ocular albinism have a normal lifespan.
- An increased risk of skin cancer exists. Careful ongoing surveillance this risk can be minimized. Since melanoma skin cancer may occur without characteristic pigmentation, a high level of dermatologic vigilance is required to ensure early diagnosis.
- Affected people usually have unaffected children unless married to another individual with albinism.
- Albinism does not cause a delay in development or intellectual disability.
Albinism – Prevention
There is no known way to prevent albinism. If you have albinism or have a family history of the disorder, you can talk to a genetic counselor when deciding to have children to understand the risks to your offspring.