The darker areas in the PSSM1 biopsy indicate the accumulation of excess glycogen and abnormal polysaccharide. Because PSSM1 is inherited in a dominant fashion the chances of an affected foal being born are dependent on the genotype of the parents as follows: Thus any time a horse with PSSM1 is bred there is a minimum chance of 50% of an affected foal being born even if the selected mate is completely normal. Scientific articles by Dr Valberg and colleagues, Mary Anne McPhail Dressage Chair in Equine Sports Medicine, Neuromuscular Diseases related to vitamin E. What is polysaccharide storage myopathy (PSSM)? You can test your horse for PSSM 1 through the University of Minnesotas Veterinary Diagnostic Laboratory. , Regular exercise is the best way to prevent and manage PSSM in horses. What causes a PSSM episode? Foals that survive to birth generally die or are euthanized within 8 weeks of age. The most common breeds that get PSSM are American Quarter Horses, Draft Horses, and Warmbloods. Insulin can further worsen PSSM because it causes the GYS1 gene to produce even more glycogen. Ataxia (incoordination) Polysaccharide storage myopathy (PSSM) is a disease that results in an abnormal accumulation of glycogen (sugar) in the muscles. The condition is most common in Draft horse breeds, but can also affect other horse breeds such as Warmbloods. The dietary recommendations based on total daily calorie intake are provided in the table belwo to help nutritionists select the most appropriate feed/. Affects: Eleven percent of American Quarter Horses. 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Valberg, S.J., Finno, C.J., Henry, M.L., Schott, M., Velez-Irizarry, D., Peng, S., McKenzie, E.C., Petersen, J.L. There is no cure for PSSM, but there are treatments that can help manage the disease and improve the horses quality of life. Muscle glycogen concentrations in affected horses are up to four times greater than in normal horses. This may relate to differences in diet, exercise and impact of different genotypes in different breeds. Get the monthly horse newsletter by email. A condition known as myofibrillar myopathy (MFM), characterized by exercise intolerance and intermittent exertional rhabdomyolysis, may be an extreme subset of PSSM2, but further research is needed. Hyperkalemic periodic paralysis HYPP is a completely separate muscle disorder in Quarter Horses from PSSM1. Valberg, S.J., Williams, Z.J., Finno, C.J., Schultz, A., Velez-Irizarry, D., Henry, M.L., Gardner, K., Petersen, J.L. 2018. How do I know if I should do the genetic test or the muscle biopsy? .hs-submit{display: inline-block; color: white;} Research conducted at the University of Minnesota has identified two types of PSSM. It was first recognized in horses with Quarter Horse bloodlines such as Quarter Horses, American Paint Horses and Appaloosas and in draft and warmblood breeds with continental European bloodlines (Belgian and Percheron, for example). McCue et al J Vet Intern Med. She is an established authority in the pet blogging community, and her blog, "Paws and Claws," has been featured in numerous publications. While the exact cause of tying-up is unknown, it is believed to be related to a buildup of lactic acid in the muscles. Polysaccharide Storage Myopathy (PSSM) - AQHA Polysaccharide Storage Myopathy (PSSM) PSSM is a disease that causes an abnormal accumulation of glycogen, the form of sugar stored in the muscle. From: 2003. Genetic testing is also part of the AQHA 5 panel genetic test and is performed at the Veterinary genetics Laboratory at the University of California Davis. This is because diet, exercise regimes and the many interactions between genes can vary from breed to breed. PSSM: Polysaccharide Storage Myopathy Disorder An autosomal dominant disease caused by mutation in the glycogen synthase 1 (GYS1) gene. Shifting lameness. The abnormal polysaccharide always remains within the muscle tissues and does not decrease in amount over time. There are two forms of PSSM: Type 1 and Type 2. CanStockPhoto/Vanell. Stop exercising the horse and move it to a box stall. U of S Researchers Take an Inside Look at the Horses Gut, Vaccination Guidelines For Healthier Horses, A Revolutionary Treatment for OCD in Horses, Diagnosis and Treatment of Equine Joint Disease. Most of the draft horse breeds are more prone to PSSM as they feed more carbohydrates. What does a blinking blue light on a smoke detector mean? The type-2 PSSM is still a condition as the exact causes are unknown. .actions{margin-top: 10px; margin-bottom: 0px;} These areas are slow to heal, and many horses with HERDA are euthanized due to slow-healing injuries. Treatment options may include: Dietary management: Feeding a low-glycogen diet can help to reduce the build-up of glycogen in muscle cells. Type 1 PSSM is caused by a mutation in the GYS1 gene. Both presentations involve muscle loss or damage and are linked to the same genetic variant. Muscle conditions affecting sport horses. @media only screen and (max-width: 768px) { Affects: Eleven percent of American Quarter Horses. If a horse is N/N but is showing signs of tying-up or muscle pain, it is possible that the horse has another muscle disorder which must be diagnosed by muscle biopsy. Valberg, S.J., Finno, C.J., Henry, M.L., Schott, M., Velez-Irizarry, D., Peng, S., McKenzie, E.C., Petersen, J.L. .hs-email{max-width: 100% !important; width: 100%; display: inline-block; vertical-align: bottom;} This will help prevent spikes in blood sugar levels and minimize the risk of glycogen build-up in the muscles. Borgia LA, Valberg SJ, McCue ME, Pagan JD, Roe CR. Chronic signs of type 1 PSSM in riding horses include a lack of energy when under saddle, reluctance to move forward, stopping and stretching as if to urinate, and a sour attitude toward exercise. Treatment will vary depending on the severity of the episode and may include IV fluids, anti-inflammatory medication and rest. The mutation causes this glycogen synthase enzyme to be overactive, increased in activity especially in the presence of insulin resulting in constant production of glycogen. Horses with PSSM can exhibit symptoms without exercise. Only one parent needs to pass the genetic mutation to its offspring for signs of tying-up to occur. Baird JD, Valberg SJ, Anderson SM, McCue ME, Mickelson JR. For horses with PSSM1, a diet high in carbohydrates and/or lack of exercise appear to exacerbate PSSM1. Rather, horses should begin small paddock turn out as soon as reluctance to move has abated. Turn out is very beneficial for PSSM1 horses as they get regular exercise during turn out, however consider the sugar content of the pasture when designing a diet. Photo: Andreas Krappweis, Main Photo: The typical horse with PSSM is in good body condition and has a calm temperament. You can read more about Exertional rhabdomyolysis here. PSSM in horses is the most frustrating disease for a horse owner. Polysaccharide storage myopathy (PSSM) in horses, Healthy Horse and Hay Price Calculator apps. Clinical signs may include reluctance to move, sweating, and muscle tremors, also known as "tying-up". How do I Remove Thompsons Water Seal from Wood? Table 1. A normal horse is designated as N/N. Important principles include 1) providing adequate time for adaptation to a new diet before commencing exercise (2 weeks), 2) recognizing that the duration of exercise is more important to restrict than the intensity of exercise (no more than 5 min walk/trot to start) 3) ensuring that exercise is gradually introduced and consistently performed and 4) minimizing any days without some form of exercise. The glycogen deposited in the cells is used for energy production. Am J Vet Res 2007;68(10):1079-1084. There are several different abbreviations used to describe polysaccharide storage myopathy including PSSM, EPSM and EPSSM. Glycogen is a type of sugar that is stored in the muscles and used for energy. PSSM1 is more commonly observed in Quarter Horses, related breeds such as Paints and Appaloosas, and draft breeds, although cases have been reported in more than 20 breeds. The symptoms of PSSM include tying-up, cramping, and muscle pain. The stallions posted DO NOT have to be negative for the diseases, but. The most susceptible horse breeds are American Quarter Horse (AQH), American Paint Horse, Thoroughbred, Cobs, Warmbloods, Dales Ponies, New Forest Pony, Morgan, Peruvian Paso, Mustang, Lipizzaner, Standardbred, and the Arabian horse. While a good balance of Omega 3 to 6 ratio may be important for other health reasons it does not appear to impact the response to fat diets in PSSM1 horses. This article will describe the signs and symptoms of PSSM and the two different types, explain options available to veterinarians to diagnose PSSM, and outline the use of diet in . Type 1 PSSM is caused by a mutation in the GYS1 gene and occurs in over 20 horse breeds. Type 1 PSSM can be inherited by autosomal dominant traits, which means that only one parent needs to pass on the genetic mutation for the offspring to contract the disease. J Anim Physiol Anim Nutr (Berl). Valberg, S.J. The form of PSSM resulting from the mutation was termed type 1 PSSM. These cases are referred to as PSSM Type 2. . BEMER's research in pain relief for horses is shaping the equine industry. Dr. Valberg and other members of the lab team have published their research on PSSM1 in many general interest and scientific articles. Insulin sensitivity and skeletal muscle glucose transport in Equine Polysaccharide Storage Myopathy. Cases of PSSM2/MFM have been reported in warmbloods and Arabians. 3) Selection of fat source: My initial approach would be to get the horse moving comfortably with a low starch/sugar diet and to get the horse into a suitable weight range before adding fat. While QHR had more exertional rhabdomyolysis than DB or WB, QHR was less likely to suffer from muscle atrophy than DB. PSSM also affects many other breeds. The most commontrigger for clinical signs of PSSM is 20 min ofexercise at a walk and trot, particularly if the horsehas been rested for several days before exercise.8Signs of exertional rhabdomyolysis include rmpainful muscles, stiffness, fasciculations, sweating,weakness, and reluctance to move. Prevalence and clinical signs of polysaccharide storage myopathy and shivers in Belgian Draft Horses. Valberg SJ. In some cases, the outer layer of the skin sloughs off entirely, leaving raw wounds. This can cause episodes of muscle stiffness and pain after exercise, also known as tying up or exertional rhabdomyolysis. What Quarter Horse Bloodlines Carry Pssm? CanStockPhoto/LByst. He was powerful and fast, which led him to be a champion in the show ring. Diagnostic Approach to Muscle Disorders. Many of his offspring followed in his success, with 36 becoming AQHA champions. The genetic test used by AQHA identifies PSSM1 mutation. Breeding and foal care Tying up in quarter horses and related breeds. With PSSM1, the intensity of this stain is very dark indicating a large amount of glycogen is present in the horse's muscle. Comparative skeletal muscle histopathologic and ultrastructural features in two forms of polysaccharide storage myopathy in horses. Equine Vet J. The Mary Anne McPhail Equine Performance Center, Office of Diversity, Equity, and Inclusion, Strategic Plan for Diversity, Equity, and Inclusion, Strategic Plan for Diversity, Equity, and Inclusion Outcomes, Application Process and Applicant Selection, Comparative Medicine and Integrative Biology, Dual-degree Program at the MSU College of Veterinary Medicine, Undergraduate Student Summer Research Program in Biomedical Sciences, I Want to be an MSU Preveterinary Student, Bovine Health Management for Early-Career Rural Veterinarians, Online Distance Education, Albert C. and Lois E. Dehn Endowed Chairs in Veterinary Medicine, David J. Ellis Endowed Chair in Antimicrobial Resistance and Large Animal Clinical Sciences, Donald R. Myers & William E. Dunlap Endowed Chair in Canine Health, McPhail Equine Neuromuscular Research Laboratory, Matilda R. Wilson Chair in Large Animal Clinical Sciences, The Gastrointestinal Stress Biology Laboratory, Meadow Brook Chair in Farm Animal Health and Well-Being, Wade O. 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The amount added is usually between 1/2 and 2 cups. There are other causes for tying-up besides PSSM, including malignant hyperthermia, glycogen branching enzyme deficiency, and myosin heavy chain myopathy, so it is important to rule these out to ensure the horse is treated appropriately. PSSM1 horses, however, will always be susceptible to this condition and if their exercise schedule is disrupted. Type 2 Polysaccharide Storage Myopathy. Neuromuscular Disorders. What is Warmblood Fragile Foal Syndrome Type 1? Continued research into PSSM in Quarter Horses resulted in the discovery of a genetic mutation in the glycogen synthase 1 gene in this herd of research horses. However, successive generations of offspring that received two defective genes often show more severe versions of the disease. When the horse can exercise for 15 minutes, a five-minute break at a walk can be provided, and then a few intervals of walk and trot can gradually be increased. The flow chart below can help to decide whether a genetic test is the best approach to investigate tying up in your horse. Horses with PSSM may not be able to graze. Valberg SJ. If only the diet is changed, we found that approximately 50% of horses improve. Quarter Horse-related breeds with type 2 PSSM also have abnormal glycogen storage, and, although the cause of this myopathy is unknown, they are fed similarly. Feed companies offer some excellent choices for exercising horses suffering from PSSM. PSSM also affects many other breeds. A horse with PSSM1 may be heterozygous P/N or rarely homozygous P/P for the mutation. The percentage of horses that have PSSM is 3%. An old theory about tying-up is that it is due to too much lactic acid in the muscle. Reintroducing exercise: Re-introduction of exercise after an acute episode of ER in PSSM1 horses needs to be gradual. For example, a 500-kg horse on a routine of light exercise generally requires 18 MCal/day of digestible energy (DE). An autosomal recessive disease caused by mutation in the GBE1 gene. Horses identified as having a moderate to severe form of the disease according to the muscle biopsy were more likely to have PSSM Type 1 than horses with a milder version of the disease. There is a 50% chance that the PSSM1-positive horses offspring will contract the disease, regardless of who the breeding partner is. Very young foals with PSSM1 occasionally show signs of severe muscle pain and weakness. Genetic testing is not performed at Michigan State University. .hs-button{background-color: #6284a9; border-radius: 3px;} If both diet and exercise are altered, then 90 percent of horses have no or few episodes of tying-up. 2007 Nov;39(6):567-75. Two types of PSSM have been classified: PSSM1 and PSSM2. J Am Vet Med 2009 Jan 1;234(1):120-5. Symptoms of PSSM can vary depending on the severity of the disease, but may include: Muscle stiffness The PSSM1 mutation is inherited in a dominant fashion, meaning that one copy of the mutation can cause PSSM1. HYPP was seen in Impressives sons and daughters because to be expressed, the disease does not require two copies of the defective gene. Once conditioned, some PSSM1 horses thrive with 4 days of exercise as long as they receive daily turn out. Valberg SJ, Mickelson JR, Gallant EM, MacLeay JM, Lentz L and De La Corte FD. Increased muscle damage due to creatine kinase enzymes. Animal Genetics (Sept e press). Horse Ownership Genetic panel and DNA test: $120 for members and $175 for nonmembers. Some affected horses, however, do not exhibit any clinical signs. Horses that test positive for P2, P3, P4, P8, or K1 should receive dietary supplementation with complete . Not all cases of tying up are caused by the PSSM1 mutation. It's likely an old genetic mutation that occurred prior to the foundation of most modern horse breeds. In severe cases, HYPP can cause collapse or sudden death. Over 10% of Quarter Horses are affected. This initial work should be very mild and very short in duration. 8.9% Warmblood breeds. . Registration forms, AQHA Transfers: The Multiple Transfer Process, GBED: glycogen branching enzyme deficiency, PSSM1: polysaccharide storage myopathy Type 1. This disorder causes the horses body to abnormally store or store too much sugar (glycogen) in the muscles. Firshman AM, Baird JD and Valberg SJ. There are currently no scientifically verified DNA tests for PSSM2, but a muscle biopsy can be performed for diagnosis. Make a Gift to the UC Davis School of Veterinary Medicine, School of Veterinary Medicine - Social Media Hub, VIPERFacultyAlumniFuture Veterinary Medical CenterCampus Directory. Cont. Dr Valberg worked with KER and Hallway Feeds (1-859 255-7602) to develop the first of these diets called Re-Leve** . Muscle weakness may lead to an inability to rise. By definition horses with PSSM1 have a distinctive genetic mutation in the gene. PSSM in horses is the abnormal deposition of polysaccharides (Glycogen) in the horses muscle cell. ** Do not feed additional selenium with this feed, as it is fully supplemented. Every horse inherits either a normal or a mutant gene form each parent. The exercise should not be laborious for every day; instead, it should continue a regular structured work. 2020. Animal Welfare and Advocacy. Horses must exercise daily to maximize the muscles ability to burn glycogen. These channels are involved in generating electrical impulses associated with muscle contraction. We advise consulting a nutritionist. Remove grain. Testing of all of the muscle samples submitted to the NMDL that were diagnosed by muscle biopsy as having PSSM showed that not all horses diagnosed with PSSM by muscle biopsy have the mutation. Many exercise studies have proven that this is absolutely not the case with PSSM1. The variety of acronyms used are in part related to preferences of different laboratories, as well as to differences in the criteria used to diagnose polysaccharide storage myopathy. Type1 PSSM is a genetic disease and can be diagnosed by a test of samples taken from blood and hair. 2020. 2008 Sep-Oct;22(5):1228-33. Muscle stiffness, sweating, and reluctance to move are common symptoms. .hs-submit{display: inline-block; color: white;} It is estimated that approximately 3 percent of horses from a variety of breeds suffer from tying-up, according to a study conducted by Valberg in 2018. Summary. 2009 Jul;41(6):597-601. 2) Selection of forage: Quarter Horses have been shown to develop a significant increase in serum insulin concentrations in response to consuming hay with an NSC of 17% , whereas insulin concentrations are fairly stable when fed hay with 12% or 4 %NSC content (Borgia et al 2011). Valberg SJ, Geyer CJ, Sorum S and Cardinet III GH. The Releve Concentrate works well for PSSM1 in moderate to heavy work that require at least 4 lbs of concentrate a day. Note: ADNA testis required for most breeding stock. hbspt.forms.create({ A horse only needs one copy of the GYS1 gene mutation to be affected by Type 1 PSSM. Affected horses may be reluctant to move and may display sweating, lameness, and muscle tremors. Reluctance to move or exercise. 2008 May 8 e pub Vet J. If the horse requires additional calories to exercise and maintain weight then dietary fat (oil) or high fat feeds can be fed. Muscle conditions affecting sport horses. | Rather than provide dietary fat to an overweight horse, fasting for 6 h prior to exercise can be used to elevate plasma free fatty acids prior to exercise and alleviate any restrictions in energy metabolism in muscle. PSSM is a condition that affects horses and is the most common in American Quarter Horses. Affected horses experience increased muscle metabolism, fever often exceeding 109 degrees F, excessive sweating, high heart rate, abnormal heart rhythm, shallow breathing, hypertension, muscle rigidity, breakdown of muscle tissue, muscle protein in the urine and/or death. Once fit, some PSSM horses thrive with as little as four days of exercise as long as they receive daily turnout. The cause of Type 2 PSSM has yet to be identified. Horses with PSSM1 can have signs typically associated with tying-up. The signs are most often seen in horses when they are put into initial training or after a lay-up period when they receive little active exercise. Your veterinarian can help you to select the best diet for your horse. formId: "d01f22bb-5b4c-4eb3-9a24-219a6869b198" }); AQHA offers a panel test for five genetic tests. The amounts are expressed as the percentage of total digestible energy (DE or megacalories) that should be fed with regard to nonstructural carbohydrates (NSC), fat, protein and forage. Horses that are managed properly can generally go on to have successful performance careers. To help breeders make informed decisions, AQHA offers a panel test for five genetic diseases. Episodes usually begin after very light exercise such as 10-20 minutes of walking and trotting. Work with a professional nutritionist to make sure your horses diet meets their needs. The signs are most often seen in horses when they are put into initial training or after a lay-up period when they receive little active turn-out. Reference: Tryon et al J Am Vet Med Assoc. There appears to be a second genetic mutation (MH) that makes signs of PSSM1 more severe in Quarter Horses and related breeds. Ribeiro W, Valberg SJ, Pagan JD and Essen Gustavsson B. An autosomal dominant disease caused by mutation in the ryanodine receptor 1 (RYR1). What is type 1 polysaccharide storage myopathy (PSSM1)? 2011 Dec;95(6):798-807. .hs-main-font-element{color: #29353d} Fed at 2% of body weight, a 12% NSC mixed grass hay almost meets their daily caloric requirement by providing 17.4 MCal/day. A recent study did not find a significant association between the commercial genetic test variants P2, P3 (a and b), and P4 and horses with a diagnosis of PSSM2 or MFM based on histopathology (the gold standard for evaluation of muscle disease). Commercial genetic testing for type 2 polysaccharide storage myopathy and myofibrillar myopathy does not correspond to a histopathological diagnosis. Perkins G, Valberg SJ, Madigan JE, Carlson GP, and Jones SL. McCue ME, Armin AG, Lucio M, Mickelson JR, Valberg SJ. Factors affecting assessment of Insulin Sensitivity in Horses. If you are benefited by reading, please share it with your friends who owned horses. Once inside the cell the muscles of PSSM horses make much more glycogen than a normal horse due to a mutated (overactive) enzyme called glycogen synthase. The mutation in the GYS1 gene causes unregulated synthesis of glycogen, which results in excessive sugar in muscle cells. Of those that adhere to dietary and exercise management, 90% have few to no episodes of tying-up. McCue ME, Valberg SJ, Lucio M and Mickelson JR. Glycogen Synthase 1 (GYS1) Mutation in Diverse Breeds with Polysaccharide Storage Myopathy. This beneficial effect requires that horses are trained daily to enhance enzymes involved in fat and glucose metabolism. Description: Collagen makes up connective tissues (skin, bones, tissue, muscles and cartilage). Breeds Affected: Animal Genetics offers DNA testing and detection for markers identifying horses that could suffer from PSSM in American Paint horses, Appaloosas, Draft Breeds, Quarter horses (horse with quarter horse blood) and Warmbloods.