About oculocutaneous albinism

What is oculocutaneous albinism?

Oculocutaneous albinism (OCA) is a group of rare inherited disorders characterized by a reduced amount or complete lack of melanin pigment in the skin, hair, and eyes. These conditions are caused by mutations in specific genes that are necessary for the production of melanin pigment in specialized cells called melanocytes. Absent or insufficient melanin pigment results abnormal development in the eyes resulting in vision abnormalities and light skin that is very susceptible to damage from the sun including skin cancer. Oculocutaneous albinism is inherited as an autosomal recessive genetic condition.

What are the symptoms for oculocutaneous albinism?

The most recognizable form of albinism results in White hair and very light-colored skin compared with siblings. Skin coloring (pigmentation) and hair color can range from white to brown, and may be nearly the same as that of parents or siblings without albinism.

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)
  • Sunburn and the inability to tan

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.

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 or stain from exposure to normal minerals in water and the environment, and appear darker with age.

Eye color

Eyelashes and eyebrows are often pale. 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 the irises 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.

Vision

Vision impairment is a key feature of all types of albinism. Eye problems and issues may include:

  • Rapid, involuntary back-and-forth movement of the eyes (nystagmus)
  • Head movements, such as bobbing or tilting the head, to try to reduce the involuntary eye movements and see better
  • 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 the eye or the lens inside the eye (astigmatism), which causes blurred vision
  • Abnormal development of the retina, resulting in reduced vision
  • Nerve signals from the retina to the brain that don't follow the usual nerve pathways (misrouting of the optic nerve)
  • Poor depth perception
  • Legal blindness (vision less than 20/200) or complete blindness

What are the causes for oculocutaneous albinism?

Autosomal recessive inheritance pattern 

To have an autosomal recessive disorder, you inherit two changed genes (mutations), one from each parent. These disorders are usually passed on by two carriers. Their health is rarely affected, but they have one changed gene (recessive gene) and one unaffected gene (dominant gene) for the condition. Two carriers have a 25% chance of having an unaffected child with two unaffected genes (left), a 50% chance of having an unaffected child who also is a carrier (middle), and a 25% chance of having an affected child with two recessive changed genes (right).

Several genes provide 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, hair and eyes.

Albinism is caused by a mutation in one of these genes. Different types of albinism can occur, based mainly on which gene mutation caused the disorder. The mutation may result in no melanin at all or a significantly reduced amount of melanin.

Types of albinism

Types of albinism are classified based on how they're inherited and on the gene that is affected.

  • Oculocutaneous albinism (OCA), the most common type, means a person inherited two copies of a mutated gene — one from each parent (autosomal recessive inheritance). It's the result of a mutation in one of seven genes, labeled from OCA1 to OCA7. OCA causes decreased pigment in the skin, hair and eyes, as well as vision problems. The amount of pigment varies by type, and the resulting color of skin, hair and eyes also varies by and within types.
  • Ocular albinism is mainly limited to the eyes, causing vision problems. The most common form is type 1, inherited by a gene mutation on the X chromosome. X-linked ocular albinism can be passed on by a mother who carries one mutated X gene to her son (X-linked recessive inheritance). Ocular albinism occurs almost exclusively in males and is much less common than OCA.
  • Albinism related to rare hereditary syndromes can occur. For example, Hermansky-Pudlak syndrome includes a form of OCA as well as bleeding and bruising problems and lung and bowel diseases. Chediak-Higashi syndrome includes a form of OCA as well as immune problems with recurrent infections, neurologic abnormalities and other serious issues.

What are the treatments for oculocutaneous albinism?

Because albinism is a genetic disorder, it can't be cured. Treatment focuses on getting proper eye care and monitoring skin for signs of abnormalities. Your care team may involve your primary care doctor and doctors specializing in eye care (ophthalmologist), skin care (dermatologist) and genetics.

Treatment generally includes:

  • Eye care. This includes receiving an annual eye exam by an ophthalmologist and most likely wearing prescription corrective lenses. Although surgery is rarely part of treatment for eye problems related to albinism, your ophthalmologist may recommend surgery on optical muscles to minimize nystagmus. Surgery to correct strabismus may make the condition less noticeable.
  • Skin care and prevention of skin cancer. This includes receiving an annual skin assessment to screen for skin cancer or lesions that can lead to cancer. An aggressive form of skin cancer called melanoma can appear as pink skin lesions.

People with Hermansky-Pudlak or Chediak-Higashi syndromes usually require regular specialized care to address medical needs and prevent complications.

What are the risk factors for oculocutaneous albinism?

Oculocutaneous albinism is a group of conditions that affect the pigmentation of the skin, hair, and eyes. Affected individuals typically have very fair skin and white or light-colored hair.

  • Long-term sun exposure greatly increases the risk of skin damage and skin cancers, including an aggressive form of skin cancer called melanoma, in people with this condition.
  • Oculocutaneous albinism also reduces pigmentation of the iris and the light-sensitive tissue of the retina.
  • Patients usually suffer from eyesight problems and photophobia – increased sensitivity to light.
  • Overall, an estimated 1 in 20,000 people worldwide are born with oculocutaneous albinism. The condition affects people in many ethnic groups and geographical regions.
  • Both males and females are equally affected. The condition does not have any age predisposition as the disease is due to an inborn error.
  • Types 1 and 2 are the most common forms of this condition; types 3 and 4 are less common. Type 2 occurs more frequently in African Americans, some Native American groups, and people from sub-Saharan Africa.
  • Oculocutaneous albinism is inherited in an autosomal recessive, which means both copies of a gene in each cell have mutations.
  • Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they do not show signs and symptoms of the condition.


Symptoms
Vision problems such as reduced sharpness,Rapid, involuntary eye movements,Increased sensitivity to light photophobia
Conditions
Nystagmus,Photophobia,Eyesight issues
Drugs
Sunscreen,Symptomatic eye treatments

Is there a cure/medications for oculocutaneous albinism?

Oculocutaneous albinism is the most common type of albinism. It is a group of rare genetic disorders characterized by a lack of pigment in the eyes and skin.

  • Affecting about one in 20,000 people worldwide, the condition is caused by mutations in specific genes that are necessary for the production of melanin pigment.
  • Lack of sufficient melanin pigment production results in abnormal development of the eyes and light skin.
  • These abnormalities could cause significant vision problems as well as skin that is susceptible to damage from the sun
  • Treatment for OCA focuses on protecting the skin from the sun and correcting eye and vision abnormalities.


Skin Protection

  • The use of sunscreens with a high SPF is key.
  • Avoidance of direct sun at midday as well as an annual skin assessment to screen for skin cancer or lesions that can lead to cancer, are also important steps.
  • This can be done by utilizing both physical and chemical oxybenzone-free sunscreen.


Eye Abnormalities

  • Make sure to get an annual eye exam by an ophthalmologist.
  • Prescription corrective lenses to improve low or poor vision may be required as well.
  • Tinted glasses/lenses to reduce light sensitivity are recommended, as is the use of UV-protected glasses.
  • Surgical corrections are also recommended for certain eye deformities.


Symptoms
Vision problems such as reduced sharpness,Rapid, involuntary eye movements,Increased sensitivity to light photophobia
Conditions
Nystagmus,Photophobia,Eyesight issues
Drugs
Sunscreen,Symptomatic eye treatments

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