What Is Albinism?
Albinism is a rare group of genetic disorders with deficiency of melanin pigment production, which causes the skin, hair or eyes to have little or no colour. It effects about 1 in 18,000 people in New Zealand.
What Are the Types of Albinism?
Traditionally albinism was classified according to the body tissue effected, such as Oculocutaneous Albinism (OCA), Ocular Albinism (OA) and rare syndrome Albinism. With improved understanding of the genetic defects, albinism is now classified more accurately based on the site of the gene defect or protein effected. Types of albinism include:
Oculocutaneous Albinism (OCA)
People with OCA have variable degree of light colour of the skin, hair, and eyes.
OCA1: is due to a defect in the Tyrosinase enzyme.
OCA1a: People with OCA1a have a complete absence of melanin, the pigment that gives skin, eyes and hair their colouring. They have white hair, very pale skin and light eyes.
OCA1b: People with OCA1b produce some melanin. They have light-coloured skin, hair and eyes. Their colouring may increase as they age.
OCA2: is less severe than OCA1 and it’s due to a defect in the OCA2 gene that results in reduced melanin production. People with OCA2 are born with light colouring and skin, and their hair may be yellow, blonde, or light brown. OCA2 is most common in Sub-Saharan Africans, African Americans and Native Americans.
OCA3: is a defect in the Tyrosinase and Tyrosinase Protein (TYRP1) gene. It usually affects dark-skinned people, particularly black South Africans. People with OCA3 have reddish-brown skin, reddish hair and hazel/brown eyes.
OCA4: is due to a defect in the Membrane Associated Transportation Protein (MATP) or SLC45A2 protein. It results in a minimal production of melanin and commonly appears in people of East Asian descent. People with OCA4 have symptoms similar to those in people with OCA2.
Ocular Albinism (OA)
OA only affects the eyes and it is the result of a gene mutation on the X chromosome and occurs almost exclusively in males. People with OA have normal hair and skin colouring but have little colouring in the iris and retina.
Hermansky-Pudlak Syndrome (HPS)
HPS is a rare form of albinism clinically similar to OCA associated with bleeding disorders due to concurrent platelet abnormalities.
Chediak-Higashi Syndrome is another rare form of albinism similar to OCA. People with Chediak-Higashi Syndrome have a defect in the white blood cells, increasing their risk of infection.
Griscelli Syndrome (GS)
GS is an extremely rare genetic disorder. It’s due to a defect in one of three genes. GS occurs with albinism (but may not affect the entire body), immune problems and neurological problems.
What Causes Albinism?
A defect in one of several genes that produce or distribute melanin causes albinism. The defective gene passes down from both parents to the child and causes albinism. Ocular albinism (OA1) is X linked and all other types of albinism are autosomal recessive.
What Are the Symptoms of Albinism?
People with albinism will have the following symptoms: an absence of or lighter than normal colour in the hair, skin or eyes.
Most children with albinism have reduced vision. Other ocular problems associated with albinism include:
- photophobia (sensitivity to light)
- nystagmus (jiggling of the eyes)
- fovea hypoplasia (poorly developed fovea tissue in macula area of the retina)
- abnormal head turn
How Is Albinism Diagnosed?
The diagnosis of albinism is made based on the evaluation of symptoms and signs by ophthalmologists, occasionally with the aid of visual evoked potential (VEP) testing. Genetic testing is the most accurate diagnosis of subtypes of albinism although it is not routinely done due to the cost and questionable benefit to the management of people with albinism.
What Are the Treatments for Albinism?
There is no cure for albinism however there are treatments available to improve the quality of the visual function in people with albinism. Many children with albinism experience some improvement of vision with aging due to the maturation of the visual system and their improved adaptations. It is important to prevent sun damage by the following strategies:
- sunglasses to protect the eyes from UV exposure & reduce photophobia
- protective clothing and sunscreen to protect the skin from UV rays
Behaviours or conditions that might indicate albinism
- Pale hair and skin.
- Pale blue or pink iris.
- Some young people may see well while others may only see bright lights and large shapes.
- Usually only the central vision is poor therefore they may have difficulty seeing small letters but appear fine at moving around.
- Blurred vision.
- Photophobia (dislike of bright light).
- Iris transillumination ( excessive red reflex from the eye).
- Both far-sightedness (hyperopia) and near sighted (myopia) can occur, and astigmatism is very common.
- Vision can range from normal to legal blindness.
- Near vision is often better than distance vision.
- Inability to see fine detail, poor depth perception, often short sighted (varied).
- Significantly reduced vision in glare or low lighting (“White out” when facing glare).
- Difficulty or inability to track moving objects, slow to change focus.
- They may have a head turn to find the null point (best position to see). This may be up, down or to one side and in fact may change according to the situation.
What to do
- The young person should visit an ophthalmologist to determine diagnosis and treatment.
- A sunhat and sunglasses may help reduce the effects of photophobia.
- Sunscreen and long sleeves (preferably dark colour to prevent glare) will be required for Oculocutaneous Albinism.
- Photochromic lenses (lenses that get darker in brighter light) can be useful.
- Specially made dark contact lenses can be made.
- Use a slope board.
- Increase the size of the print.
- Trial optical aids.
- Seat the young person so their back is to any glare from windows or lights and also avoid shadows on their work. Seating between rows of fluorescent lights is often the best.
- Wear a peaked hat in class if the glare from overhead lights is causing a problem.
- Use technology such as tablets, magnifiers, laptops, CCTV etc. to assist with access.
- Offer visual breaks during intense periods of work or focus.