A lysosomal storage disorder of the epidermis characterized by a deficiency of α-mannosidase and an accumulation of mannose-rich materials

Abstract

Laboratory investigation of a patient diagnosed as ichthyosiform erythroderma bullosa revealed the following abnormalities: (1) alpha- and beta-galactosidases were elevated in the lesion. (2) alpha-mannosidase activity was extremely low both in the lesion and in relatively normal epidermis. (3) The mannose:glucose ratio of water-soluble hexose-containing material in the scales was very high. (4) Membrane-limited vacuoles, apparently enlarged secondary lysosomes, were observed. We conclude that this patients is the first documented example of a lysosomal storage disease in which overt clinical lesions are confined to the epidermis.