title: A case of galactosialidosis.
abstract: Galactosialidosis is a lysosomal storage disease associated with a combined deficiency of beta-galactosidase and neuraminidase, caused by a defect of another lysosomal protein, the protective protein. Three subtypes are recognized: the early infantile form, the late infantile form and the juvenile/adult form. We saw a patient with galactosialidosis of the juvenile/adult form, a 51-year-old Japanese man with angiokeratomas on both elbows and knees, myoclonus, ataxia, mental retardation and macular cherry-red spots. An electron-microscopic study of a skin biopsy showed membrane-limited vacuoles in the cytoplasm of the endothelial cells, pericytes and fibroblasts. Assays of enzymatic activity in cultured fibroblasts showed a marked decrease in both beta-galactosidase and neuraminidase (sialidase). The substance contained in the cytoplasmic vacuoles appears to be glycoproteins with sialic acid, which is a terminal glycosyl residue, because the cytoplasm of the endothelial cells of the vessels and pericytes are stained by the Limax flavus agglutinin, a lectin that binds specifically with sialic acid. This technology may be useful for easy investigation of the distribution of the accumulation of such substances in the central nervous system.
authors.affiliation: Department of Dermatology, The Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo 105-8461, Japan. nobederm@pc5.so-net.ne.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Nobeyama
authors.forename: M
authors.initials: M
authors.lastname: Honda
authors.forename: M
authors.initials: M
authors.lastname: Niimura
mesh_terms: D000794:Angiokeratoma / Q000473:pathology; D006801:Humans; D016464:Lysosomal Storage Diseases / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009439:Neuraminidase / Q000172:deficiency*; D012867:Skin / Q000648:ultrastructure; D012878:Skin Neoplasms / Q000473:pathology; D001616:beta-Galactosidase / Q000172:deficiency*
chemical_list: D009439:Neuraminidase; D001616:beta-Galactosidase