Albinism

What is albinism?

Albinism is a rare genetic condition where you have less of a pigment called melanin in your eyes, specifically in the iris (the coloured part of the eye) and the retina (the light-sensitive layer at the back of the eye). Usually you'll also have less melanin in your hair and skin.

People with albinism usually have poor eyesight from birth. Although this sight loss is permanent, it does not worsen over time. 

It is estimated that 1 in 5,000 to 1 in 15,000 people in Sub-Saharan Africa are affected by albinism. In Europe and North America, it affects approximately 1 in 17,000 to 20,000 people. 

What are the different types of albinism?

There are two main types of albinism:

Oculocutaneous albinism (OCA)

This is the most common type of albinism, affecting the skin, hair, and eyes. OCA is caused by faults in one of eight genes, OCA1 to OCA8, and causes decreased pigment in the skin, hair, and eyes.

Ocular albinism (OA)

This is a rarer type that affects the eyes, but not the skin and hair. It’s much less common than OCA.  The optic nerve fibres of people with ocular albinism do not follow the usual routes to the brain, which affects their ability to correctly interpret the light that enters the eye into images.

The most common type is ocular albinism type 1 (OA1). This is also known as X-linked ocular albinism or Nettleship-Falls ocular albinism. Estimates suggest it affects at least one in every 60,000 males in the UK. While females can also be affected, it is extremely rare.

Other forms of ocular albinism are much rarer and may be associated with additional signs and symptoms, such as hearing loss. These are usually syndromes and include Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and Griscelli syndrome. In some cases, the genetic cause of the condition is often unknown. 

What causes albinism?

Albinism is caused by a fault in one of the genes involved in the production of melanin or the products used to make it. Melanin is important for healthy eye development - without it, the retina and optic nerve (which sends visual information from the retina to the brain) may not develop properly.

People with albinism will have an underdeveloped area in the centre of their retina called the fovea, which is responsible for sharp vision.

The OCA genes (OCA1 to OCA8), which cause oculocutaneous albinism, mainly affect the enzymes the body uses to generate melanin or other important molecules in the melanin synthesis pathway. Some of the genes (such as OCA1 and OCA3) are related to the coding or control of these enzymes. Other genes (such as OCA2) appear to be related to changing the acidity of the environment in which the enzymes operate.

Understanding the normal function of these genes has greatly enhanced our understanding of the complex and sophisticated way our body controls pigmentation. There are likely to be more genes and mechanisms that are yet to be discovered in the not too distant future.

What are the signs and symptoms of albinism?

People with albinism typically have very light or white skin and hair, and they may have light-colored eyes, which can appear pink or red. Vision problems are common - usually the eye cannot process sharply focused images, resulting in blurred vision.

Other symptoms include 

• nystagmus – involuntary eye movements where the eyes move constantly, usually back and forth horizontally. People may adopt a head posture to hold their eyes in the position where nystagmus is the most quiet.
• strabismus – crossed eyes or squint, where the two eyes look in different directions.
• photophobia – sensitivity to light or glare
• astigmatism – a slight difference in the shape of your eye, which can cause blurred vision

How is albinism diagnosed?

An ophthalmologist may carry out several different tests to diagnose albinism. These may include:

• Clinical examinations – to look for nystagmus, strabismus, or photophobia.
• Family history – to find out if any other family members are affected.
• Examination of the iris – to look for signs of reduced pigmentation.
• Retinal examination – to see if they have foveal dysplasia.
• Visual function tests – however, reduced visual acuity may not be noticeable until the child is old enough to recognize objects.
• Genetic testing – a blood test to identify faults in the GPR143 gene may be used to confirm a diagnosis. This can also help inform genetic counselling for other family members.

Is albinism serious?

Albinism often causes blurred vision that can affect ability to carry out everyday activities such as reading, driving or recognising faces. People with albinism usually can read with the help of larger print text.

These sight problems are present at birth and cannot be fully corrected to normal even with glasses or contact lenses. However, they will not worsen over time. 

What are the treatments for albinism?

There is currently no cure for albinism. There are some things that can help improve the lives of people living with the condition. These include:

• Corrective eyewear – as a child gets older, it’s likely they will usually need to wear glasses or contact lenses to help improve their vision. They should have their eyes tested every year to make sure they have the right prescription.
• Low-vision aids – people may benefit from vision aids such as large-print or high-contrast books and printed materials, handheld magnifying lenses, large computer screens, or speech-to-text conversion software.
• Sun protection – wearing sunglasses, tinted glasses, or a hat with a wide brim outdoors can help with sensitivity to light.
• Surgery – an operation that involves dividing and then reattaching some of the eye muscles may sometimes be an option for nystagmus.

What research is there into albinism?

Research into albinism has focused on understanding the underlying genetic mechanisms and identifying potential opportunities to treat these Scientists are also exploring novel treatment strategies, including gene therapy or drug treatments aimed at correcting the underlying causes of the condition. These developments hold promise for improving the management and quality of life for people with ocular albinism.