Albinism
DEFINITION
Albinism includes a group of inherited disorders that are characterized by little or no production of the pigment melanin. The type and amount of melanin your body produces determines the color of your skin, hair and eyes. Most people with albinism are sensitive to sun exposure and are at increased risk of developing skin cancer.
Although there’s no cure for albinism, people with the disorder can take steps to protect their skin and maximize their vision. Some people with albinism may feel socially isolated or experience discrimination.
CAUSES
Albinism is caused by a mutation in one of several genes. Each of these genes provides instructions for making one of several proteins involved in the production of melanin. Melanin is produced by cells called melanocytes, which are found in your skin and eyes. A mutation may result in no melanin at all or a significant decline in the amount of melanin.
In some types of albinism, a person must inherit two copies of a mutated gene — one from each parent — in order to have albinism (recessive inheritance).
Impact on eye development
Regardless of which gene mutation is present, vision impairment is a key feature of all types of albinism. These impairments are caused by irregular development of the optic nerve pathways from the eye to the brain and from abnormal development of the retina.
Types of albinism
Types of albinism, based mainly on which mutated gene caused the disorder, include:
- Oculocutaneous albinism. Oculocutaneous (ok-u-low-ku-TAY-nee-us) albinism is caused by a mutation in one of four genes. People with oculocutaneous albinism (OCA) type 1 have milky white skin, white hair and blue eyes at birth. Some people with OCA type 1 never experience an increase in pigmentation, but others begin to produce melanin during early childhood. Their hair may become a golden blond, brown or red, and their irises may change color and lose some translucence.
- OCA type 2 is most common in sub-Saharan Africans, African-Americans and Native Americans. The hair may be yellow, auburn, ginger or red, the eyes can be blue-gray or tan, and the skin is white at birth. With sun exposure, the skin may, over time, develop freckles, moles or lentigines.
- People with OCA type 3, mainly found in black South Africans, usually have reddish-brown skin, ginger or reddish hair, and hazel or brown eyes. OCA type 4 looks similar to type 2 and is most often found in people of East Asian descent.
- X-linked ocular albinism. The cause of X-linked ocular albinism, which occurs almost exclusively in males, is a gene mutation on the X chromosome. People who have ocular albinism have vision problems, but their skin, hair and eye color are generally in the normal range or slightly lighter than that of others in the family.
- Hermansky-Pudlak syndrome. Hermansky-Pudlak syndrome is a rare albinism disorder caused by a mutation in one of at least eight different genes. The disorder is much more common in Puerto Rico. People with this disorder have signs and symptoms similar to people with oculocutaneous albinism, but they may also develop lung and bowel diseases, or a bleeding disorder.
- Chediak-Higashi syndrome. Chediak-Higashi syndrome is a rare form of albinism associated with a mutation in the LYST gene. With signs and symptoms similar to oculocutaneous albinism, the hair is usually brown or blond with a silvery sheen, and the skin is usually creamy white to grayish. People with this syndrome have a defect in white blood cells that increases their risk of infections.
SYMPTOMS
Signs of albinism are usually, but not always, apparent in a person’s skin, hair and eye color. However, all people with the disorder experience vision problems.
Skin
Although the most recognizable form of albinism results in white hair and pinkish skin, skin coloring (pigmentation) can range from white to brown, and may be nearly the same as that of parents or siblings without albinism.
For some people with albinism, skin pigmentation never changes. For others, melanin production may begin or increase during childhood and the teen years, resulting in slight changes in pigmentation. With exposure to the sun, some people may develop:
Freckles
- Moles, with or without pigment — moles without pigment are generally pink-colored
- Large freckle-like spots (lentigines)
- The ability to tan
Hair
- Hair color can range from very white to brown. People of African or Asian descent who have albinism may have hair color that’s yellow, reddish or brown. Hair color may also darken by early adulthood.
Eye color
- Eye color can range from very light blue to brown and may change with age.
- The lack of pigment in the colored part of the eyes (irises) makes them somewhat translucent. This means that the irises can’t completely block light from entering the eye. Because of this, very light-colored eyes may appear red in some lighting. This occurs because you’re seeing light reflected off the back of the eye and passing back out through the iris again — similar to the red-eye that occurs in a flash phot.
Vision
Signs and symptoms of albinism related to eye function include:
- Rapid, involuntary back-and-forth movement of the eyes (nystagmus)
- Inability of both eyes to stay directed at the same point or to move in unison (strabismus)
- Extreme nearsightedness or farsightedness
- Sensitivity to light (photophobia)
- Abnormal curvature of the front surface of your eye or the lens inside your eye (astigmatism), which causes blurred vision
When to see a doctor
- If your child lacks pigment in his or her hair or skin at birth that affects the eyelashes and eyebrows — as is often the case in infants with albinism — your doctor will likely order an eye exam and closely follow any changes in your child’s pigmentation.
- For some infants, the first sign of albinism is poor visual tracking. This may be followed at 3 to 4 months of age by rapid back-and-forth shifting (nystagmus) in the eyes. If you observe these signs in your baby, talk to your doctor.
- Contact your doctor if your child with albinism experiences frequent nosebleeds, easy bruising or chronic infections. These signs and symptoms may indicate the presence of Hermansky-Pudlak or Chediak-Higashi syndromes, which are rare but serious genetic disorders.
