Alcohol-Responsive Myoclonus In Type I Sialidosis

Sialidosis type I is in the differential diagnosis for cherry red spots, along with other lysosomal storage disorders such as; Gangliosidosis I (GMI), Tay Sachs disease, Sandhoff disease, Niemann Pick disease Type A, B, C, and D, Sialidosis type II, Farber; lipogranulomatosis, Goldberg Syndrome, Metachromatic leukodystrophy, multiple sulfatase deficiency, and Wolman disease plus; vascular conditions such as a central retinal artery occlusion, dapsone poisoning, and traumatic ischemia. Visual findings in Sialidosis; type I include lens opacities, color vision impairment, night blindness, nystagmus, corneal opacities, loss of visual acuity, and a; macular cherry red spot. In lysosomal storage disorders, such as Sialidosis, cherry red macular spots are caused by the storage of; oligosaccharides and sphingolipids in the retinal ganglionic cell layer leading to a pale macula surrounding the fovea. Patients with; Sialidosis type I may have visual impairment, progressive myoclonus, ataxia, epilepsy, and usually normal intellect. Correct identification of involuntary limb movements as myoclonus as well as accurate recognition of a cherry red spot in the retina in various ethnicities may be challenging. Then, proper generation of a differential diagnosis and targeted diagnostic work up for a combination of cherry red spots, cerebellar dysfunction, and myoclonus is required. Confirmation of the diagnosis may be made by urinary oligosaccharides, urinary bound sialic acid excretion, and enzyme assay in leukocytes and cultured fibroblasts - or with multigene sequencing. In this case, we describe a man with a macular cherry red spot and alcohol-responsive myoclonus who ultimately received the correct diagnosis of Sialidosis Type I