The genetics of generalized vitiligo and associated autoimmune diseases

Vitiligo is an acquired disorder in which patches of depigmented skin and often overlying hair, and mucous membranes, are the result of progressive autoimmune loss of melanocytes from the involved areas. Considered the most common pigmentary disorder, vitiligo involves complex interaction of environmental and genetic factors that ultimately contribute to melanocyte destruction, resulting in the characteristic depigmented lesions. In the past few years, studies of the genetic epidemiology of vitiligo have led to the recognition that generalized vitiligo is part of a broader autoimmune disease diathesis. Attempts to identify genes involved in susceptibility to generalized vitiligo have involved gene expression studies, genetic association studies of candidate genes, and genome-wide linkage analyses to discover new genes. These studies have begun to yield results that shed light on the mechanisms of vitiligo pathogenesis. It is anticipated that the discovery of biological pathways of vitiligo pathogenesis will provide novel targets for future approaches to the treatment and prevention of vitiligo and its associated autoimmune diseases.

The genetics of generalized vitiligo and associated autoimmune diseases

Generalized vitiligo is an acquired disorder in which patches of depigmented skin, overlying hair, and oral mucosa result from progressive autoimmune loss of melanocytes from the involved areas. Although vitiligo is perhaps the most common pigmentary disorder, insufficiently clear clinical definition of the disorder and lack of a good laboratory animal model have inhibited progress in understanding its pathobiology, its environmental triggers, and in developing specific and effective therapeutic approaches. Vitiligo results from a complex interaction of environmental, genetic, and immunologic factors, which ultimately contribute to melanocyte destruction, resulting in the characteristic depigmented lesions. In the past few years, studies of the genetic epidemiology of generalized vitiligo have led to the recognition that vitiligo is part of a broader, genetically-determined, autoimmune/autoinflammatory diathesis. Attempts to identify genes involved in vitiligo susceptibility have involved both allelic association studies of candidate genes and genome-wide linkage analyses to discover new genes, and these studies have begun to shed light on the mechanisms of vitiligo pathogenesis. It is anticipated that the discovery of biological pathways of vitiligo pathogenesis will provide novel therapeutic and prophylactic targets for future approaches to the treatment and prevention of vitiligo and its associated autoimmune diseases.

Vitiligo: a new classification and therapy

Local injection of physostigmine revealed that dermatomally distributed vitiligo was associated with a dysfunction of the sympathetic nerves in the affected skin and that non-dermatomally distributed vitiligo was not. These observations led to the hypothesis that the primary disturbance of dermatomally distributed vitiligo lies in the sympathetic nerves of the affected area and that non-dermatomally distributed vitiligo has its primary disturbance in the melanocyte itself, where an autoimmune mechanism is suspect. Results of therapy supported this hypothesis by showing that topical cortisteroid is effective only in the latter, while the former reacts to oral nialamide. It is proposed that non-dermatomally distributed vitiligo be referred to as Type A and dermatomally distributed vitiligo as Type B.

Serum anti-tumour antibodies and auto-antibodies in vitiligo

Anti-tumour antibody was sought in the sera of three groups of patients; idiopathic vitiligo, malignant melanoma and miscellaneous skin disorders. No precipitating antibody to a series of prepared pigmented tumour antigens was demonstrated. All sera were tested for a number of auto-antibodies. No significant differences were detected between the groups. The evidence for an immunological factor in the causation of vitiligo remains circumstantial only.