The Tanzanian human albino skin. Natural history

Abstract

Three hundred fifty albinos in the city of Dar‐es‐Salaam have been registered at the Tanzania Tumor Centre. Their skin changes were followed for at least 2 years. Chronic skin damage was evident in all albinos by the first year of life; by 20 years, the skin of every subject demonstrated subclinical malignant change, and some had clinical epitheliomas. Untreated, the latter tumors become intractable and disseminate, usually causing death in the third or fourth decade of life. Four clinical stages could be identified, each one associated with distinct pathologic changes: Stage 1, erythema; Stage 2, epidermal atrophy with dermal hypertrophy; Stage 3, solar keratosis; and Stage 4, clinical carcinoma (under 3 cm). It was found that clinical Stage 2 only occurs in those skin areas that show evidence of previous Stage 1 change. Similarly, Stage 3 occurs only in areas that have gone through Stages 1 and 2. Stage 4 cancers were only found in those areas that had gone through all of the three prior stages. During the 2‐year period of this study, 104 skin cancers, both early and advanced, were recorded at the albino skin clinic. Thirty‐three of the 104 cancers were advanced (over 4 cm in diameter). The median age of the latter group was 31.0 years. Whereas there was no sex bias in the distribution of clinical cancer, 28 of the 33 advanced cancers were in men. Histologically, the great majority of the advanced tumors were squamous cell carcinomas: 29 of 33. There was one melanoma and three basal cell tumors. The predominant site of advanced cancers in the study group was the head and neck region (30 patients); the other three occurred on the trunk, which is generally covered by clothes.

UV causation of melanoma in Xiphophorus is dominated by melanin photosensitized oxidant production

“…Further evidence is found in studies of albino black populations in Africa, who as expected are much more sensitive to UVB-mediated events such as sunburn and skin carcinomas (42) because of the lack of melanin pigment photoprotection in high solar fluxes. However, the incidence of melanoma in this population is exceptionally low (42,43), supporting the conclusion that melanin is normally the central photosensitizer in melanocytes that is responsible for melanoma causation in humans (44).…”

Skin Cancer in African Albinos

“…As a consequence these persons lack the protective effect of melanin against ultraviolet radiation damage. The Nigerian albino is particularly predisposed to skin cancer, because of the proximity of this country to the equator and consequently high intensity of ultraviolet light (5,6).…”

Oculocutaneous albinism type 2 (OCA2) with homozygous 2.7-kb deletion of the P gene and sickle cell disease in a Cameroonian family. Identification of a common TAG haplotype in the mutated P gene

“…OCA2 is the most common form of albinism, especially among Africans and African-Americans. There is a high incidence of OCA2 among specific African populations: 1 in 1,100 among the Ibo of Nigeria (Okoro 1975), 1 in 3,900 in South Africa (Kromberg and Jenkins 1982), 1 in 4,100 in Tanzania (Luande et al 1985), 1 in 4,882 in Zimbabwe (Lund 1996), 1 in 5,000 in Nigeria (Barnicot, 1952), 1 in 7,900 among the Bamileke of Cameroon (Aquaron 1980(Aquaron , 1990 and 1 in 10,000 in African-Americans (Durham-Pierre et al 1996). The most common mutation in the P gene among Africans and African-Americans is a 2.7-kb deletion that removes a single exon (exon 7; amino acids 216-270) and results in a frameshift mutation in the first luminal loop of the P polypeptide, producing a truncated and non-functional gene product ).…”