The etiology of LS was not well defined, but there is a general agreement regarding the auto-immune nature of this disease (6,11); more specifically, anogenital lesions have been associated to extracellular matrix 1 (ECM1) protein destructions, which may be mediated by circulating IgG antibodies and, furthermore, might also be associated to ECM1 autoreactivity (6,14). The gene discussed is ECM1; the disease is Leigh syndrome.