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

• OCA3 (Oculocutaneous Albinism Type 3)

What is Oculocutaneous Albinism Type 3? (Definition/Background Information)

• Oculocutaneous albinism (OCA) is a genetic abnormality characterized by a partial or complete absence of the pigment melanin, which imparts color to the eyes, hair, and skin. There are seven different types of OCA based on the gene mutation causing the condition
• Oculocutaneous Albinism Type 3 (OCA3) is an uncommon but mild subtype of OCA. The condition is inherited in an autosomal recessive manner and caused by mutations on the TYRP1 gene. It 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 (if necessary) are the main treatment modalities considered for this disorder. Oculocutaneous Albinism Type 3 is a genetic condition that cannot be prevented. However, the prognosis is good in most cases, and the affected individuals can lead a normal quality of life

Who gets Oculocutaneous Albinism Type 3? (Age and Sex Distribution)

• Oculocutaneous Albinism Type 3 (OCA3) is an inherited disorder, and occurs most commonly in the South African population with a prevalence of 1: 8,500
• The onset of symptoms may occur at birth
• Both genders may be affected by this disorder
• OCA3 may be seen worldwide, but southern Africans may be more vulnerable to a specific form of the disorder

What are the Risk Factors for Oculocutaneous Albinism Type 3? (Predisposing Factors)

• A positive family history may be an important risk factor, since Oculocutaneous Albinism Type 3 can be inherited
• Children of consanguineous parents may bear an increased risk of developing this disorder

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 Type 3? (Etiology)

• Oculocutaneous Albinism Type 3 (OCA3) is caused by mutation(s) in TYRP1 gene, which codes for a protein associated with tyrosinase. The pigmentation in individuals with OCA3 may not be very low
• Two types of phenotypes may be observed in OCA3:
  • Rufous oculocutaneous albinism (ROCA) - it is characterized by red-bronze skin color, blue or brown irises and ginger-red hair
  • Brown oculocutaneous albinism (BOCA) - it is less common with light to brown hair and a light to brown or tan skin color
• The condition (OCA3) is inherited in an autosomal recessive manner

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Oculocutaneous Albinism Type 3?

The signs and symptoms of Oculocutaneous Albinism Type 3 (OCA3) may vary between the affected individuals but are known to be generally mild. The signs and symptoms may include:

• Pale white, yellow, or lighter than normal color of skin
• Hair of reddish discoloration
• Skin patches (partial or total albinism)
• Pale blue, red, or purple iris (eye)
• Blurred vision
• Sensitivity of eyes to light
• Nystagmus - (irregular and continuous eye movement)
• Strabismus or crossed eyes
• Sun-exposed areas may present freckles
• Sensitivity of skin to light

How is Oculocutaneous Albinism Type 3 Diagnosed?

Oculocutaneous Albinism Type 3 is diagnosed on the basis of the following tests and exams:

• A thorough physical examination and evaluation of family medical history
• 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
• 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 Type 3?

Oculocutaneous Albinism Type 3 can lead to complications such as:

• Emotional stress
• Extreme sensitivity of eyes and skin to light
• Severe sunburns with exposure to sun
• Vision defects
• Social isolation due to skin color change
• Vision loss that may affect the quality of life

How is Oculocutaneous Albinism Type 3 Treated?

The treatment measures for Oculocutaneous Albinism Type 3 generally focus on protecting the skin from sunburns and correcting eye abnormalities. The following are the common methods of treatment employed:

• 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

Surgical correction of eye defects, such as strabismus and nystagmus, may be undertaken (if required) following an evaluation by the healthcare provider.

How can Oculocutaneous Albinism Type 3 be Prevented?

Oculocutaneous Albinism Type 3 is a genetic disorder, and presently, 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 (OCA).

What is the Prognosis of Oculocutaneous Albinism Type 3? (Outcomes/Resolutions)

The prognosis of Oculocutaneous Albinism Type 3 (OCA3) is generally good, since the condition is not life-threatening. Individuals with OCA3 are reported to have normal life expectancies. Also, the condition is usually known to be mild.

Additional and Relevant Useful Information for Oculocutaneous Albinism Type 3:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/healthy-living/skin-disorders/