There is a difference between the clinical types of albinism and the genetic types of albinism. With advances in genetic research, additional types of albinism are being discovered and identified, with increased ability to classify those who don’t normally fit into a “traditional” albinism diagnosis.
Clinical Types of Albinism
For many years medical professionals have thought that they were mostly oculocutaneous albinism on one hand, and ocular albinism on the other, and in very rare cases, syndromic albinism – Hermansky-Pudlak Syndrome (HPS) and Chediak-Higashi syndrome (CHS).
Ophthalmologists make a clinical diagnosis of albinism when they observe lack of pigment and foveal hypoplasia in the retina with low measured visual acuity. Other possible indications to support this may be nystagmus, strabismus, lack of depth perception and long or short sightedness.
Where the person lacks colouring in hair and skin or is significantly lighter in colour than their parents, they will generally add the diagnosis of Oculocutaneous Albinism. When the person has pigment in hair and skin similar to parents, they generally diagnose Ocular Albinism.
Today, at least in the Caucasian population, it has been shown that clinically, people with albinism can go from a complete lack of pigmentation in the hair and skin to a somewhat normal pigmentation, with no clear distinction between those with some pigmentation and those without.
In other words, many people with albinism (PWA) can’t be easily classified as OA or OCA because they may have some pigmentation and fall somewhere in between OA and OCA. There is some thinking that all clinical diagnosis should be as Albinism and the type left to genetic testing.
Genetic Types of Albinism
Genetic testing is the only reliable way to accurately diagnose albinism, especially in those who do not fit into the traditional clinical diagnosis of OA or OCA.
Up until mid 2020, 21 different albinism genes have been discovered, resulting in 21 different types of albinism. The identified 21 genetic types so far are OCA 1 to 8, (some have sub-variants), OA, HPS 1 to 11 and CHS.
Adding to the complexity, many PWA who look alike (in terms of pigmentation) and have the same visual impairment, don’t necessarily have the same genetic type of albinism.
Someone with normal skin and hair colouring may be clinically diagnosed with OA, when in fact it is possible that they may have a variant of OCA or HPS. Therefore the names of OA and OCA, which were chosen years ago, can be misleading.
Most of the OCA and HPS genes can lead to a pigmented appearance and those with no apparent colouring may have the extremely rare HPS. If a person with albinism has excessive bruising or bleeding, they should be genetically tested for HPS so that early medical treatment can take place.
As new discoveries have recently been made and the understanding of different types of albinism is changing, we have delayed including any more detail here at present. We are working with professionals in other organisations in order to bring you the latest accurate information.
Resources
We are working to bring you more information about recent research into the different forms of albinism.
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