Biology and genetics of oculocutaneous albinism and vitiligo - common pigmentation disorders in southern Africa.

[oculocutaneous albinism]

Pigmentation disorders span the genetic spectrum from single -gene autosomal recessive disorders such as oculocutaneous albinism (OCA ), the autosomal dominant disorder piebaldism to X-linked ocular albinism and multifactorial vitiligo . OCA connotes a group of disorders that result in hypopigmented skin due to decreased melanin production in melanocytes and loss of visual acuity . There are four non-syndromic forms , OCA 1 -4 , which are classified based on the gene that is mutated (tyrosinase , OCA 2 , tyrosinase-related protein 1 and SLC 45 A 2 , respectively ). Despite the fact that multiple genes account for the various forms of OCA , the phenotypes of all four forms result from disruption in the maturation and trafficking of the enzyme tyrosinase . OCA 2 is the most prevalent autosomal recessive disorder among southern African blacks , affecting 1 /3 900 individuals ; while OCA 3 , although rare , is most prevalent in southern Africa . Another common pigmentation disorder in southern Africa is vitiligo , which affects 1 - 2 % of people worldwide . Vitiligo is a complex , acquired disorder in which melanocytes are destroyed due to an autoimmune response . The aetiology underlying this disorder is poorly understood , although recent genetic association studies have begun to shed light on the contributing factors . Pigmentation disorders have significant psychosocial implications and co -morbidities , yet therapies are still lacking . Recent progress in our understanding of the pathobiology of both albinism and vitiligo may herald novel treatment strategies for these disorders .Â

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oculocutaneous albinism

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