title: Incidence of polysaccharide storage myopathy: necropsy study of 225 horses.
abstract: Muscle samples were obtained at necropsy from 225 horses and ponies 1 year of age or older. Samples were processed in routine manner and were stained with hematoxylin and eosin and with periodic acid-Schiff for glycogen. Sections were examined for abnormal glycogen content and amylase-resistant complex polysaccharide and for chronic myopathic change (excessive fiber size variation, increase in number of internal nuclei). A total of 101 horses and ponies with lesions of polysaccharide storage myopathy were identified. Age of affected horses ranged from one to 30 years, with a mean of 14.7 years. Mean age of nonaffected horses was 12 years. Incidence of polysaccharide storage myopathy varied depending on breed; Thoroughbreds had the lowest (27%) and draft-related horses had the highest (86%) incidence. Chronic myopathic changes were more severe in polysaccharide storage myopathy-affected horses than in nonaffected horses. Results of this study indicate that polysaccharide storage myopathy is a common disorder of many breeds of horses and ponies.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Magruder 142, Oregon State University, Corvallis, OR 97331, USA. Beth.Valentine@oregonstate.edu
authors.forename: B A
authors.initials: BA
authors.lastname: Valentine
authors.forename: B J
authors.initials: BJ
authors.lastname: Cooper
mesh_terms: D000818:Animals; D002239:Carbohydrate Metabolism, Inborn Errors / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D005260:Female; D006003:Glycogen / Q000378:metabolism; D006734:Horse Diseases / Q000453:epidemiology* / Q000473:pathology*; D006736:Horses; D015994:Incidence; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D013045:Species Specificity
chemical_list: D006003:Glycogen