Albinism

What is albinism?

Albinism is a condition in which people have little or no melanin pigment (compound that creates colour) in their eyes, skin or hair. Because of this people with albinism look a little different from other members of their family without albinism. They have very fair skin, which is prone to sunburn, their hair is white or a very light colour, and they may squint a lot as their eyes are sensitive to sunlight.

Classification of albinism

There are two main categories of albinism: oculocutaneous and ocular albinism.

Oculocutaneous

• Involves dilution of the colour of the hair, skin and eyes
• Most common form of albinism

Ocular

• Melanin pigment mainly missing from the eyes while the skin and hair appear normal or only slightly lighter
• Accounts for 10-15% of all albinism cases

Oculocutaneous albinism (OCA) make up a group of different types of albinism based on the specific albinism gene involved. Oculocutaneous albinism type 1 and type 2 are the most common types of oculocutaneous albinism.

OCA 1A

• Absent tyrosinase activity
• Eyes: blue grey, reduced visual acuity
• Hair: white at birth, may become yellow over time
• Skin: white, moles are non-pigmented

OCA 1B

• Reduced tyrosinase activity
• Variable dilution of skin and hair pigment
• Temperature-sensitive subtype

OCA 2OCA 2 mutation (previously P gene)

• Variable dilution of skin and hair pigment
• Over time, develop solar lentigines on sun-exposed skin
• Prader-Willi and Angelman-associated (chromosome 15)

OCA 3TYRP 1 mutation

• Reduced eumelanin synthesis
• Rufous/red and brown subtypes

OCA 4SLC45A2 mutation (previously MAPT)

• Similar to OCA 2
• Most common type in Japan, China and India

Prenatal testing for OCA is available in some centres.

Other less common types of albinism include:

• Hermansky-Pudlak syndrome
• Cross syndrome
• Chediak-Higashi syndrome
• Griscelli syndrome.

How do you get albinism?

Albinism is mostly a recessively inherited disease, which means two albinism genes are inherited (one from each parent). If the patient's parents are only carriers of albinism (each having one albinism gene and one normal gene), they will have enough genetic information to make normal pigment and will not show any signs of albinism.

Who is at risk of albinism?

Albinism occurs worldwide and affects people of all races. Males and females alike can have the condition although ocular albinism occurs primarily in males.

About 1 in 70 people have a gene for albinism. Couples whom are each carriers of the recessive albinism gene have a 1 in 4 chance of producing a child with albinism.

What are the problems associated with albinism?

The main problems of albinism are caused by the inability of the body to produce melanin pigment (whose major role in the skin is to absorb UV light from the sun so skin is not sun-damaged). It also has a role in the development of normal vision of the eye. Having white or light coloured hair due to lack of melanin is no cause for concern, however, lack of melanin in the skin and eyes can cause the following problems:

Skin problems

• Easily sunburned
• Increased chance of getting skin cancer, mainly cutaneous squamous cell carcinoma and basal cell carcinoma

Eye problems

• Impaired vision: although not blind, vision is impaired and may not be fully corrected with glasses. Varying degrees of near-sightedness or far-sightedness exist.
• Photophobia: sensitivity to light or glare
• Nystagmus: involuntary movement of the eyes back and forth
• Strabismus: eyes do not fixate and track together
• Retinal involvement: this is an important area of the eye as it is responsible for sending signals to the brain. Impaired transmission of signals causes various vision disorders

Other less common types of albinism may also involve problems with blood clotting, immune deficiency or problems with hearing.

One concern that should not be overlooked is the risk of isolation in people with albinism. People with albinism, especially children need to be treated normally and included in all activities. They develop normally and have normal intelligence, it is a myth that people with albinism are mentally impaired or intellectually-challenged.

What treatment or precautions can be taken?

It is important for people with albinism to protect themselves from UV exposure and thus prevent the damaging effects it can have on the skin.

• Sun avoidance methods
  • Wear protective clothing (long sleeves and pants, shirts with collars, tightly woven fabrics that don't let light through), hats (wide-brimmed) and eyewear (specifically made to protect from UV rays)
  • Use broad-spectrum sunscreens with SPF of 50 or greater: apply to all exposed areas
• Undergo frequent skin examinations by someone who has been taught to recognise signs of skin cancer.

Because the patient has no, or little, pigmentation, skin cancers will often have no or little pigmentation. Patients with albinism should promptly report suspicious spots or growths to a doctor.

Specialist eye doctors cannot cure eye problems but can help with various optical aids to improve vision for people with albinism.