Mother holding her albino baby in her arm in Tanzania. Traditionally, albinism has been classified according to clinical phenotype, and the 2 main categories are oculocutaneous albinism (OCA) and ocular albinism (OA).
The albinism subtypes were reclassified in 2009. With the availability of new molecular genetic studies, the classification of albinism has shifted emphasis to genotype as opposed to phenotype alone. Hence, this has led to redefining existing phenotypic categories and the addition of new subtypes based on specific genetic mutations. The following is a brief overview of the current classification of albinism.
OCA is characterized by the reduction or absence of melanin in the skin, hair, and optic system (including the eyes and optic nerves). The lack of skin pigment results in a pale skin appearance and an increased risk of skin cancer. As shown in Table 1, OCA is divided further into several subtypes based on the distinct genetic mutation.
ALBINISM IN AFRICA AS PUBLIC HEALTH ISSUE
Oculocutaneous albinism (OCA) is a genetically inherited autosomal recessive condition and OCA2, tyrosine-positive albinism, is the most prevalent type found throughout Africa. Due to the lack of melanin, people with albinism are more susceptible to the harmful effects of ultraviolet radiation exposure. This population must deal with issues such as photophobia, decreased visual acuity, extreme sun sensitivity and skin cancer. People with albinism also face social discrimination as a result of their difference in appearance. The World Health Organization is currently investigating the issues concerning this vulnerable population.
Systematic electronic search of articles in PubMed concerning albinism in Africa. Furthermore, a World Health Organization (WHO) pilot survey of albinism was drafted in English, French and Portuguese, and distributed to African countries through WHO African Regional Offices (AFRO) in an attempt to gather further information on albinism.
Epidemiologic data on albinism, such as prevalence, were available for South Africa, Zimbabwe, Tanzania and Nigeria. Prevalences as high as 1 in 1,000 were reported for selected populations in Zimbabwe and other specific ethnic groups in Southern Africa. An overall estimate of albinism prevalences ranges from 1/5,000 – 1/15,000. In addition, both the literature review and the survey underscored the medical and social issues facing people with albinism.
The estimated prevalence of albinism suggests the existence of tens of thousands of people living with albinism in Africa. This finding reiterates the need for increased awareness of and public health interventions for albinism in order to better address the medical, psychological and social needs of this vulnerable population.
Oculocutaneous albinism (OCA) encompasses a heterogeneous group of genetic conditions with an autosomal recessive inheritance. It is characterized by hypopigmentation of the skin, hair and eyes due to a reduced or lack of cutaneous melanin pigment production . Consequently, in Africa, the affected individuals have sandy coloured hair, white chalky skin and light brown or blue eyes, making them more susceptible to the harmful effects of ultraviolet (UV) radiation.
There are two types of OCA: tyrosinase negative (OCA1) and tyrosinase positive (OCA2). In OCA1, there is little or no melanin production due to the lack of a functional tyrosinase, the critical enzyme required in the melanin biosynthetic pathway. In the more prevalent OCA2 type  there is some level of tyrosinase activity, thereby producing some red-yellow photomelanin pigment that gives rise to sandy coloured hair and light brown irises .
There is growing evidence of social discrimination and stigmatization directed towards this population [4,5]. Along with their differences in appearance, a lack of knowledge about albinism in the community leads to such stigma. For example, the etiological beliefs about albinism continue to be heavily influenced by culture and superstition, rather than genetics . The goal of this review is to discuss the current knowledge on public health aspects of albinism in Africa, focusing on the epidemiology as well as medical and social issues. We also recommend further actions to alleviate this situation for the affected populations and countries. As a basis for the review we conducted a systematic literature search on albinism in Africa and conducted a survey among African WHO Member States.