What are the other Names for this Condition? (Also known as/Synonyms)

• OCA (Oculocutaneous Albinism)
• Platinum Oculocutaneous Albinism
• Yellow Oculocutaneous Albinism

What is Oculocutaneous Albinism? (Definition/Background Information)

• Oculocutaneous Albinism (OCA) is a genetic abnormality characterized by a partial or complete absence of the pigment melanin. Melanin imparts color to the eyes, hair, and skin
• OCA is the most widespread type of albinism amongst all races. It is subdivided into 7 forms (OCA1 to OCA7), based on the gene mutation that causes the condition. Of the 7 forms, OCA1 and OCA2 are the most common
• Lack of or reduced pigmentation in eyes, either alone or in combination with very pale skin and hair, as well as light-sensitivity of the eyes and skin, are the major symptoms of this condition. Oculocutaneous Albinism is diagnosed on the basis of symptoms, vision exams, and genetic tests, if necessary
• Protecting the skin and eyes from sunlight and corrective surgery for vision abnormalities are the main treatment modalities considered for this disorder. Oculocutaneous Albinism is a genetic condition that cannot be prevented. However, the prognosis is excellent in most cases, and the affected individuals can lead a normal quality of life

Who gets Oculocutaneous Albinism? (Age and Sex Distribution)

• Oculocutaneous Albinism affects individuals of all races and ethnicities
• It is estimated that the disorder occurs at a frequency of 1:17,000, with types 1 and 2 being the predominant forms of OCA
• The overall prevalence of OCA subtypes are given below, although they can vary depending on specific populations:
  • OCA1 - with predominant reports of OCA1A, 1: 40,000
  • OCA2 - depending on the population, the frequency varies between 1: 1,500 and 1: 40,000
  • OCA4 - 1:100,000
  • OCA5 - so far it has been reported in a single family
  • OCA6 - so far it has been reported in two individuals, one each from China and India
  • OCA7 - reported in some individuals in Denmark and Lithuania
• Both male and female genders are equally susceptible to Oculocutaneous Albinism
• Although seen worldwide, some populations may be more vulnerable to a specific form of the disorder. Examples of susceptibility are given below:
  • OCA type 2 - African-Americans, some native American populations, and individuals from sub-Saharan Africa
  • OCA type 3 -  southern Africa
  • OCA type 4 - some Asian populations (Japanese and Korean)

What are the Risk Factors for Oculocutaneous Albinism? (Predisposing Factors)

• Since Oculocutaneous Albinism is a genetic condition, having a family history of the condition is a major risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Oculocutaneous Albinism? (Etiology)

Oculocutaneous Albinism is caused by mutation(s) in at least 7 genes involved in the production and distribution of the pigment melanin. The specific gene mutation forms the basis of the classification of OCA into seven subtypes:

• OCA1, or tyrosine-related albinism, results from a mutation in the gene coding for the enzyme tyrosinase, which catalyzes conversion of the amino acid tyrosine to melanin. There are 2 sub-forms of OCA1:
  • OCA1A - it is characterized by the absence of tyrosinase
  • OCA1B - in which individuals produce low amounts of the enzyme 
• OCA2 is caused by defects in the OCA2 gene coding for P protein, which facilitates tyrosinase action. Individuals with OCA2 produce melanin in reduced quantities
• OCA3, a rare disorder, develops as a result of mutation(s) in TYRP1 gene, which codes for a protein associated with tyrosinase. The pigmentation in individuals with OCA3 may not be very low
• OCA4 is caused by defects in the SLC45A2 gene. The protein coded by this gene facilitates the function of tyrosinase, and the affected individuals have decreased melanin synthesis, similar to OCA2
• OCA5 has been mapped to chromosome 4, and is a rare subtype of OCA
• OCA6 is a rare disorder, and is caused by mutations in the SLC24A5 gene
• OCA7 is also rare, and is caused by mutations in the C10orf11 gene

All forms of Oculocutaneous Albinism are inherited in an autosomal recessive pattern. In this type of inheritance, an individual must possess both copies of the causative gene in the defective form in every cell of his/her body for the condition to manifest itself. An affected individual inherits one defective copy from each parent. The parents are carriers of the condition and are generally not affected.

What are the Signs and Symptoms of Oculocutaneous Albinism?

The signs and symptoms of Oculocutaneous Albinism may vary between affected individuals, based on the type of mutation(s) they inherit, which dictate the amounts of melanin in their body. The symptoms of OCA may include:

• Pale white, yellow, or lighter than normal color of skin and hair
• Patchiness on the skin may be observed
• Sensitivity of skin to light
• Pale blue, red, or purple iris (eye)
• Decreased vision/visual clarity
• Blurred vision
• Sensitivity of eyes to light
• Nystagmus - an irregular and continuous eye movement
• Astigmatism - formation of distorted images in the retina
• Strabismus - crossed eyes
• Macular hypoplasia – improper development of the macula, which is a part of retina involved in vision clarity

How is Oculocutaneous Albinism Diagnosed?

Oculocutaneous Albinism is diagnosed on the basis of the following tests and exams:

• A thorough physical examination and assessment of symptoms
• A visual assessment of pigmentation in hair, skin, and eyes of the affected individual, to reach a preliminary diagnosis of the likely mutation and form of OCA in the individual
• An evaluation of family medical history
• Examination of the eyes for structural abnormalities
• Vision exam
• Visual-evoked potential (VEP) testing in children with visual problems
• Prenatal genetic testing for checking causative gene mutations in the fetus, if a family history of albinism is present

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Oculocutaneous Albinism?

Oculocutaneous Albinism can lead to complications such as:

• Extreme sensitivity of eyes and skin to light
• Severe sunburns with exposure to sun
• Skin cancer
• Vision defects
• Social isolation, due to skin color change, which may affect the quality of life

How is Oculocutaneous Albinism Treated?

The treatment measures for Oculocutaneous Albinism generally focus on protecting the skin from sunburns and correcting eye abnormalities. The following are the common methods of treatment:

• For skin protection: Use of sunscreens with a high SPF (sun protection factor), protective clothing, and avoiding midday exposure
• For eye abnormalities:
  • Visual aids to help low or poor vision
  • Tinted glasses to reduce light-sensitivity
  • Use of UV-protected sunglasses
  • Use of wide-brimmed hats for sunny days

A surgical correction of eye defects, such as strabismus and nystagmus, may be undertaken following evaluation by the healthcare provider.

How can Oculocutaneous Albinism be Prevented?

• Oculocutaneous Albinism is a genetic disorder, and at the present time, there are no specific methods or guidelines to prevent this condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Regular medical and vision examinations are highly recommended to monitor changes in skin and visual acuity

Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Oculocutaneous Albinism.

What is the Prognosis of Oculocutaneous Albinism? (Outcomes/Resolutions)

• The prognosis of Oculocutaneous Albinism is generally good, as the affected individuals are reported to have normal life expectancy
• However, due to light-sensitivity of both the eyes and skin, the choice of activities/profession may be limited, for some individuals
• There is an increased susceptibility to skin cancers and other malignant melanomas in individuals with OCA. However, with early diagnosis and prompt treatment, the outcomes can be positive

Additional and Relevant Useful Information for Oculocutaneous Albinism:

• Oculocutaneous Albinism is also known by the following additional synonyms:
  • Minimal Pigment Oculocutaneous Albinism
  • Temperature-Sensitive Oculocutaneous Albinism
• A variant of Oculocutaneous Albinism, known as Hermansky-Pudlak syndrome is caused by mutations in nine different genes, causing nine subtypes of the disease. Apart from the reduced/lack of pigmentation in the eyes, skin, and hair, the affected individuals also have bleeding problems and easy bruising