TYPES OF ALBINISM IN THE BLACK SOUTHERN AFRICA POPULATION.

Abstract

BACKGROUND Oculocutaneous albinism (OCA) is the most common inherited disorder in Southern African blacks and several types have been described. Molecular techniques, where available, can be used to confirm a clinical diagnosis and the type of OCA, if necessary, and for prenatal diagnosis. OBJECTIVES To investigate and classify the different types of albinism commonly found and to determine the clinical implications for each type. DESIGN A descriptive survey. SETTING Gauteng province, South Africa, and Lesotho. SUBJECTS Three groups of subjects with OCA (96 from a genetics clinic, 62 from a dermatology clinic, and 31 from community surveys) from the black African population participated. MAIN OUTCOME MEASURES Subjects underwent clinical and/or dermatological examinations and were then classified according to type of OCA. RESULTS Four forms of OCA were identified: most (82%) subjects had OCA2 (a tyrosinase- positive type) with three sub-types: those without large freckles (ephelides) on exposed areas (named OCA 2a in this study), those with such freckles (named OCA 2b), and those with brown albinism (BOCA); the remainder had red/rufous albinism, ROCA (OCA 3). The four forms could be distinguished from each other clinically without using molecular genetic testing. CONCLUSION The most common types of albinism found in the black population of Southern Africa are OCA2 and OCA3. Given the high prevalence of the disorder, together with the high risk of skin cancer, and the recent persecution of affected individuals in certain East African countries, these findings and their clinical implications have significance in terms of both education and awareness for health professionals and lay people caring for those with albinism.