Oculocutaneous albinism, often referred to as OCA, is a genetic condition that typically affects pigmentation of skin and hair color. For instance, those affected by this genetic disorder may have fair skin and light-colored or white hair.
The condition also affects vision and skin cancer risk. It’s often further classified into types.
What are Type 1 and Type 2?
Although there are more than two types of Oculocutaneous albinism, the most common are type 1 and type 2. In Oculocutaneous albinism type 1, also known as OCA1, the skin tends to be fair and the hair white while the eyes have light colored irises.
OCA1 is further classified as OCA1A and OCA1B. Individuals with OCA1A typically produce no melanin 1.
Oculocutaneous albinism type 2, also known as OCA2, occurs throughout the world, but its prevalence is highest in African populations 2. OCA2 causes a continuum of hair, skin, and eye color ranging from minimal to near normal.
OCA typically causes a spectrum of visual issues including nystagmus (involuntary eye movements), reduced visual clarity (ranging from 20/25 to 2/400), foveal hypoplasia (underdevelopment of part of the retina which can be worsened by sunlight exposure), and strabismus (eyes are unable to work together appropriately). Strabismus is caused by misrouting of the optic nerve fiber.
There are currently 7 known types of OCA.
Someone with this disorder will have a normal life span assuming they follow proper medical advice to
avoid prolonged sun exposure and use proper sun protection. Individuals with Hermansky-Pudlak syndrome, a rare type of albinism, may have life shortening lung issues 5.
How is Oculocutaneous Albinism Inherited?
While each person has two copies of each gene, parents of children with OCA typically each only have one copy of the gene mutation, or gene change causing dysfunction of the gene. Consequently, they do not show any sign of the genetic disorder.
This is called “autosomal recessive inheritance”. Parents who have one copy of the gene mutation are called “carriers”. When two carrier parents have a child who inherits both copies of the gene mutation, one from each parent, the child will have OCA.
If a parent has OCA, meaning they have two gene mutations, one in each copy of the gene, the other parent must still be a carrier for the child to potentially inherit OCA.
What Causes Oculocutaneous Albinism?
Mutations in a number of genes controls how melanin, which is within the melanocytes, is synthesized. OCA is an autosomal recessive genetic disorder caused by changes, or mutations, in certain genes. Each type of OCA is caused by mutations in a specific gene.
For instance, mutations in the TYR gene cause Oculocutaneous albinism type 1. Mutations in the OCA2 gene (also known as the P gene) cause Oculocutaneous albinism type 2.
We have 46 chromosomes in each cell of our bodies. These chromosomes can be organized into 23 pairs.
One of each pair of chromosomes is inherited from each parent. Our genetic information, or our genes, is carried on the chromosomes. Genes are instructions telling our bodies how to grow and develop.
OCA occurs when an individual inherits two mutations in a specific gene for that type of OCA. For example, OCA1 occurs when an individual inherits two TYR gene mutations, one from each parent.
If two healthy parents have a child with OCA, this means that they are each carriers of OCA, meaning they have one working copy of the specific OCA gene and one nonworking copy of the OCA gene. The working copy of the gene is sufficient for the carrier to be unaffected with OCA.
Two carrier parents have a 25% chance (1/4) of having a child with OCA with each pregnancy. Two carrier parents have a 50% chance (1/2) of having a child who is an unaffected carrier with each pregnancy. They have a 25% (1/4) chance of having a child who is an unaffected non-carrier with each pregnancy.
Diagnosis of Oculocutaneous Albinism
The primary symptoms of Oculocutaneous albinism are greatly reduced amounts of color in skin, hair, and eyes. In addition, there are usually vision problems.
However, besides type 1 and type 2, there are also 5 other types.
Here are some of the main differences in symptoms between the various types 6:
- White hair
- Pale skin
- Light-colored irises
- Less severe symptoms compared to Type 1
- Creamy-white skin
- Hair is light brown, light yellow, or blond
Type 3 (Also known as Rufous oculocutaneous albinism):
- More commonly affects dark-skinned populations
- Reddish to brown skin color
- Hair is red or ginger
- Brown or hazel irises
- Similar to Type 2
How Do You Diagnose Oculocutaneous Albinism?
Diagnosis must come from a physician. You can gain suspicion about potential Oculocutaneous albinism by appearance.
For instance, in OCA1, the skin will appear pale, the hair light colored or white, and the eyes may have a white iris.
How Do Doctors Diagnose for Oculocutaneous Albinism?
A doctor can diagnose Oculocutaneous albinism in three ways: appearance, an eye examination and genetic testing.
First, a doctor may notice there is hypopigmentation of the skin and hair. The doctor may also notice if there are any ocular problems such as nystagmus.
Sometimes it is difficult to diagnose hypopigmentation based on appearance if the child’s family has very pale skin and hair color. This is easier to detect in people with darker skin colors in their family.
Nystagmus is typically present by the third month of infancy.
Next, an ophthalmologist can do an exam, potentially including a VEP test. This will reveal vision problems related to the disorder.
Finally, genetic testing can provide an accurate diagnosis as well as confirm type. However, genetic testing may not be necessary if the clinical diagnosis if obvious.
Can I test for Oculocutaneous Albinism during pregnancy?
Oculocutaneous albinism is inherited in an autosomal recessive pattern 7. This means that an individual has two mutations, one on each copy of the gene for their particular type of OCA.
If parents believe that they might pass on the mutation to an offspring, they can get genetic counseling and ask for a prenatal diagnosis.
In the past, a prenatal diagnosis was attempted based on an electron microscopic examination of a fetal skin biopsy, but now advances in genetic testing makes it possible to detect the presence of genetic mutations prenatally via chorionic villus sampling (CVS) or amniocentesis if the mutations are known in the family.
Genetic Tests for Oculocutaneous Albinism
Although it’s possible for a health care provider to diagnose OCA through appearance and confirm a diagnosis after an ophthalmologist performs a thorough eye examination, the best way to discern the correct type is through genetic testing of the seven genes responsible for the condition.
Genetic testing may conclusively confirm the type of OCA because a physical evaluation by a doctor alone could be erroneous as type 2 and type 4 have a similar physical appearance. In the case of someone with African ancestry, which tends to have a higher frequency of OCA2, a genetic evaluation should include testing for 2.7 kb exon deletion.
Are They Available?
Genetic testing for Oculocutaneous albinism is available for prenatal diagnosis and for testing relatives for known variants. It’s also available to confirm a diagnosis. Testing is typically ordered by a physician or a genetic counselor.
DNA Testing to Spot or Detect Oculocutaneous Albinism Early
Oculocutaneous albinism can be spotted before birth through a molecular genetic method 8.
This approach makes it possible to identify the two mutated TYR genes that code the tyrosinase. Currently, more than sixty mutations have been discovered.
How to Test for Oculocutaneous Albinism
Oculocutaneous Albinism is inherited. It is an autosomal recessive genetic condition.
Due to genetic mutation, there is a disruption of cellular function and the cell’s ability to produce melanin. These mutations are responsible for reduced pigmentation in the skin and hair. Several genes could be responsible for these mutations.
They can include, but are not limited to, TYR, OCA2, TYRP1, as well as SLC45A2.
DNA Tests Currently Available for Oculocutaneous Albinism
A genetic test is a medical examination to detect any possible changes, called pathogenic variants or mutations, in the genes.
DNA tests for albinism are available through a doctor or genetic counselor. The testing typically includes a panel of genes associated with the different types of Oculocutaneous albinism.
If an individual is found to have two mutations, one in each copy of the specific gene, then the diagnosis is confirmed. Sometimes, results can be inconclusive and samples from the individual’s parents are necessary to clarify results.
Where Can I Go For a Genetic Test For my Child?
Although, you can find your local genetic testing service on your own using a variety of directory services, it is advisable to go to a genetic counselor, geneticist,
or ophthalmologist with experience in OCA who will then be able to provide guidance on the appropriate genetic testing based on the symptoms.
DNA Testing for Oculocutaneous Albinism: Strengths and Limitations
Genetic testing for Oculocutaneous albinism has a mix of strengths and limitations. There is no possibility of physical harm or any biological risk in getting tested aside from the general risk of a blood draw if a blood draw is completed.
Although deciding on testing is entirely voluntary, it can prove to be a complex decision that may raise new health concerns or anxieties. For this reason, it’s best to seek genetic counseling to help discuss the emotional and social aspects of genetic testing, as well as get an educated interpretation of the results.
With that in mind, here is a short list of the strengths and limitations:
Strengths of DNA Testing for Oculocutaneous Albinism:
- You will get relief from any uncertainty about whether or not OCA is the appropriate diagnosis..
- You will get in-depth understanding about the specific type of Oculocutaneous albinism.
- You will be in a position to educate your family about the potential risk of passing down the condition or help diagnose other family members who also have Oculocutaneous albinism.
Limitations of DNA Testing for Oculocutaneous Albinism:
- Your new knowledge will not lead to a cure, but will help you make decisions about how to ameliorate possible health issues related to Oculocutaneous albinism.
- You may not be able to get a conclusive answer after genetic testing which may then lead to a feeling of uncertainty about the diagnosis and family planning.
What Are the Chances That I Will Pass Oculocutaneous Albinism Onto my Child?
Oculocutaneous albinism is a genetic condition resulting in hypopigmentation and vision changes. If both parents are genetically tested then the following possibilities arise:
- If neither parent has the gene mutation; that is, neither parent is a genetic carrier, then it is highly unlikely that Oculocutaneous albinism will be passed down.
- If only one parent has a gene mutation; that is, the parent has a gene change for OCA but is unaffected by it because he or she is only a genetic carrier, the children of that carrier parent each have a 50 percent chance (1/2) of being an unaffected genetic carrier of the disorder.
- If both parents have an Oculocutaneous albinism gene mutation, meaning they are unaffected carriers,, it does not necessarily mean that their child will have Oculocutaneous albinism unless the child inherits both copies of the gene mutation, one from each parent. In fact, a couple who both have the gene mutation (carriers) and who have a number of children may have some with Oculocutaneous albinism and some without Oculocutaneous albinism. The chance for a carrier parents to have a child with OCA is 25% (1/4) with each pregnancy. Therefore, there is a 75% chance (3/4) with each pregnancy that their child will not have OCA.
If I Have one Child with Oculocutaneous Albinism Will all my Children Have it?
Oculocutaneous albinism can be passed from one generation to another if one or both of the parents has OCA or if one or both parents is a genetic carrier.
Testing for Oculocutaneous Albinism on a Pregnancy or Before a Pregnancy is Achieved
Prenatal diagnosis of OCA used to be limited to a histologic examination (the use of an electron microscope) of a fetal skin biopsy.
However, advances in genetics now makes prenatal molecular testing possible. This type of testing can be useful if both parents have been diagnosed as having the gene mutation (even though they may show no sign of Oculocutaneous albinism because they are only genetic carriers.)
Molecular genetic testing can be performed in different ways depending on when the testing is completed (i.e. before a pregnancy is achieved, timing during a pregnancy). There are risks associated with this testing. It is best to discuss these options with a genetic counselor.
Who does Oculocutaneous Albinism Typically Affect?
Oculocutaneous albinism can be seen in individuals of all ethnic backgrounds, male and female. The prevalence is estimated to range between 1-in-17,000 to 1-in-20,000 9. However, about 1-in-70 people may be a carrier of an OCA gene mutation.
Depending on the type of OCA, certain ethnic populations may have OCA more frequently. For instance, OCA type 2 occurs more frequently in African Americans, some Native American groups, and people from sub-Saharan Africa.
OCA type 3 has been described more commonly in people from southern Africa. OCA type 4 seems to occur more frequently in people from Japan and Korea 10.
Does Oculocutaneous Albinism Occur in Children?
Oculocutaneous Albinism is an inherited condition. Therefore, it is present at birth. However, features may be less obvious in certain individuals leading to a delayed diagnosis.
It affects both males and females, and can occur in any ethnic group or in any part of the world.
Oculocutaneous Albinism Treatment Options
Treatment options are limited to providing preventive care to ameliorate the symptoms of the condition.
Is Oculocutaneous Albinism Treatable?
Since Oculocutaneous albinism is an inherited disorder that cannot be cured, treatment is based on prevention.
The Prognosis for Oculocutaneous Albinism
Oculocutaneous albinism cannot be treated, but the right care options can assist a person with this condition to enjoy an active life and experience a natural lifespan.
The prognosis is only negative if insufficient care options are taken into consideration because of a lack of proper medical advice, willingness to follow preventative care instructions, or lack of availability of sun protection. For instance, a person with the disorder who lives in a tropical climate might have excessive sun exposure.
Excessive sun exposure can lead to higher risks of skin cancer.
Although the prognosis for Oculocutaneous albinism is positive if proper lifestyle choices are made based on medical recommendations, in some cases, the disorder may be confused with other more complicated forms of albinism like Griscelli syndrome, Chediak-Higashi syndrome or Hermansky-Pudlak syndrome.
Griscelli syndrome creates an immunodeficiency that can reduce life span, Chediak-Higashi syndrome creates peripheral neuropathy and pyogenic infections (pus-producing infections) due to a decrease in phagocytosis (the ingestion of bacteria by phagocytes), and Hermansky-Pudlak syndrome is a form of albinism typically associated with increased bleeding, bruising, and lung disease that can be life shortening.
Does Oculocutaneous Albinism Go Away?
Oculocutaneous albinism is an inherited lifelong disorder and does not go away.
Is There a Cure for Oculocutaneous Albinism?
There is no cure for Oculocutaneous albinism but sufficient care options will relieve many of the symptoms associated with sun damage to skin and can improve visual acuity.
What are Oculocutaneous Albinism Care Options?
Numerous care options are available for Oculocutaneous albinism.
Here is a list of recommended care options a doctor might make for someone with this condition 11:
- Individuals should visit an ophthalmologist to determine the extent of the vision concerns of the disorder. This initial examination will establish a medical record baseline of the condition, which will help with monitoring eye health and vision over the years. Recommendations will be made for options to help visual acuity, including glasses or contact lenses when appropriate. Annual examinations are recommended. Strabismus surgery may be discussed in certain cases. Low vision resources may be recommended for school and other activities. Dark glasses or transition lenses may be helpful, but some individuals with OCA prefer to go without them since they may decrease acuity. Photodysphoria (light sensitivity) can be further reduced by wearing a wide-brimmed hat. This has the added bonus of protecting the face from sun.
- An individual with OCA should be followed by a dermatologist, and an evaluation should occur soon after diagnosis. A dermatologist will discuss appropriate sun protection based on the type of OCA. These recommendations may include wearing long-sleeved shirts rather than short-sleeved shirts and trousers or a long skirt rather than shorts or a short skirt whenever exposed to sunlight. Avoiding sunburn will also reduce sun damage and the risk of skin cancer. A dermatologist will recommend regular follow-up to evaluate the skin for changes.
- A genetics evaluation may be recommended to clarify the type of OCA, discuss natural history of the condition, and discuss inheritance and recurrence risks in future pregnancies.
Summary and Outcomes
Since Oculocutaneous albinism is present at birth, it’s considered an inherited genetic disorder. Those who are at risk for getting this rare disorder are individuals whose parents have the disorder or who are genetic carriers.
The symptoms of this disorder are a reduction of melanin pigmentation in the skin and hair, as well as light-colored irises and vision concerns. As a result, someone with Oculocutaneous albinism may have lighter skin, hair, and eye color than other members of the family.
The disorder is also characterized by one or more vision problems. These include strabismus, a condition that causes crossed eyes and problems with eye alignment; photodysphoria, a condition that causes sensitivity to light; nystagmus, a condition that causes involuntary rapid eye movements; and decreased visual acuity.
Diagnosis can range from rudimentary to highly precise. A rudimentary diagnosis is based on a doctor’s physical evaluation.
A more accurate diagnosis includes an ophthalmologist performing a thorough examination. Finally, a highly accurate diagnosis is based on genetic testing to detect the gene mutations and determine the type of OCA present. There are currently 7 type of OCA known to date.
Since the disorder is passed down to children via gene mutations typically present at conception, there is currently no technology for repair of these genetic mutations. Although there is no cure for Oculocutaneous albinism, a great deal can be done when it comes to limiting sun damage.
These preventive steps can include the use of the right type of vision correction and sun shielding glasses and hats; periodic visits to an ophthalmologist (at least once a year) to stay current on prescription eyewear.
It’s also a good idea to wear hats and long garments to cover the chest, arms, and legs. Sun damage can be reduced by using the right strength of sunblock lotion when an individual with OCA is exposed to direct sunlight. Nystagmus may improve on its own over time.
The outcome for OCA is positive if the person with this disorder receives early medical diagnosis and takes proper steps to avoid sun damage.
However, given sufficient medical care and advice, as well as making positive lifestyle decisions, the disorder does not limit a person’s potential to achieve a fulfilling life.
Unlike other types of genetic disorders, Oculocutaneous albinism does not place any limits on intelligence, fertility, or life span. Due to vision concerns, some individuals may not pass the vision requirements for driving, but some individuals are able to obtain a driver’s license.
In communities of color, certain social stigmas may be present when paternity or race is questioned. It is important to educate family and teachers of the diagnosis to prevent isolation. It may help for the family to connect with other families with albinism 12.
- Lewis RA. Oculocutaneous Albinism Type 1. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019. 2000 Jan 19 [Updated 2013 May 16]. ↩
- Estimation of carrier frequency of a 2.7 kb deletion allele of the P gene associated with OCA2 in African‐Americans
Donna Durham‐Pierre Richard A. King John M. Naber Steve Laken Murray H. Brilliant. 1996. ↩
- Lewis RA. Oculocutaneous Albinism Type 1. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019. 2000 Jan 19 [Updated 2013 May 16]. ↩
- Lewis RA. Oculocutaneous Albinism Type 2. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019. 2003 Jul 17 [Updated 2012 Aug 16]. ↩
- Hermansky-Pudlak Syndrome. Huizing M, Malicdan MCV, Gochuico BR, et al. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019. 2000 Jul 24 [Updated 2017 Oct 26]. ↩
- Oculocutaneous Albinism.
National Organization for Rare Disorders (NORD). Retrieved Online June 2019. ↩
- Mutations of the P Gene in Oculocutaneous Albinism, Ocular Albinism, and Prader-Willi Syndrome Plus Albinism
Seung-Taek Lee, Robert D. Nicholls, Sarah Bundey, Renata Laxova, Maria Musarella, and Richard A. Spritz. 24 February 1994. ↩
- DNA‐based carrier detection and prenatal diagnosis of tyrosinase‐negative oculocutaneous albinism (OCA1A)
Tzipora C. Falik‐Borenstein MD Stuart A. Holmes Zvi Borochowitz Abi Levin A. Rosenmann Richard A. Spritz. April 1995. ↩
- Oculocutaneous Albinism. (n.d.). Retrieved June 10, 2019, from NORD (National Organization for Rare Disorders). 2009. ↩
- Oculocutaneous albinism. Genetics Home Reference. Retrieved June 10, 2019. ↩
- Oculocutaneous Albinism Type 1. In M. P. Adam, H. H. Ardinger, R. A. Pagon, S. E. Wallace, L. J. Bean, K. Stephens, & A. Amemiya (Eds.), GeneReviews®. Lewis, R. A. (1993). ↩
- Information Bulletin – What is albinism? National Organization for Albinism and Hypopigmentation. (2018, January 27). Retrieved June 10, 2019. ↩