Pssm2 in horses. PSSM2 occurs far less commonly.

Pssm2 in horses diseases of the musculature. Phenotype: Horses with Type 1 Polysaccharide Storage Myopathy (PSSM1) have a muscle disease characterized by accumulation of abnormal complex sugars (glycogen) in skeletal muscles. Feeding a Horse with PSSM As with other horses prone to tying-up, dietary management of PSSM horses is key, with the aim being to reduce soluble carbohydrate intake as much as possible. ) should not be used for breeding. Dr. Warmblood horses reportedly have both PSSM1 and PSSM2. Typical symptoms can include unexplained lameness, muscle stiffness, difficulties with gait changes/coordination, reluctance to move, muscle atrophy and/or difficulty Horses with PSSM1 should have minimal starch and sugar in their diets. Our test detects only PSSM1. The three main sectors of management are diet, exercise, and body work: of those three, two (exercise and body work) are a form of physical work/manipulation. The classic symptoms of PSSM include a reluctance to move, stiffness, sweating, and muscle tremors, and a propensity for “tying-up”. It is a frequent cause of exertional rhabdomyolysis in horses, accounting for 40 per In fact, for PSSM1 and PSSM2 in Quarter Horses where the problem is too much glycogen, the management recommendations are identical. Dietary recommendations for PSSM2 are not as well defined, but PSSM2 horses don’t seem to be as sensitive to dietary starch and sugar levels as PSSM1 horses. PSSM1 and PSSM2/MFM are the names of diseases. Muscle biopsies taken from these horses also show abnormal accumulation and/or location of glycogen. It is currently known to affect the following breeds American Quarter Horses, American Paint Horses, Warmbloods, Cobs, Dales Ponies, Thoroughbreds, Arabians, New Forest ponies, and a large number of Heavy horse Stiffness and discomfort: Affected horses may exhibit stiffness, especially during exercise or after periods of rest. PSSM2 occurs far less commonly. PSSM2 – refers to all PSSM cases that aren’t caused by genetic mutation GYS1 and so there may be more than one further subset identified in due course. The first was taken in March 2018, before PSSM2 genes were discovered and before I got his management locked down (keep in mind his Researchers determined that the diet and exercise recommendations veterinarians make for horses with PSSM1 can help improve, but likely won't eliminate, clinical signs of PSSM2 in Warmbloods. After a tying up episode, depending on the severity, horses are often initially placed on stall rest during the episode and are prescribed an anti-inflammatory pain medication such as Banamine® (flunixin meglumine). Further Thoughts. These horses have normal muscle glycogen Understanding PSSM in Horses When a horse frequently accumulates glycogen in his or her muscle fibers, it’s possible the horse is experiencing a condition commonly referred to as either Equine Polysaccharide Storage Myopathy Exertional Rhabdomyolysis (ER), commonly known as tying-up or azoturia, is an exercise-induced condition in horses characterized by the excessive breakdown of muscle tissue. Yearlings can be fed 8 lbs RE-LEVE and a A familial basis for PSSM2-QH was previously suggested by the fact that excessive glycogen storage occurred in three breeds that share a common genetic background, Quarter Horse, American Paint Horse and Appaloosa. 9 In Horses with PSSM have up to 4 times the amount of muscle glycogen concentration as compared to normal horses. Most type 1 PSSM horses are easy keepers and do well on a forage-based diet, but vitamin, mineral, and most notably, vitamin E supplementation, are all important for these horses. our test does not detect the, yet unknown, PSSM2 PSSM is a debilitating up to even life-threatening glycogen storage myopathy which is highly prevalent in multiple breeds of horses. Type 1 Polysaccharide Storage Myopathy (PSSM1) is a hereditary muscular disorder in horses that results in abnormal accumulation of glycogen (a stored form of sugar) and an abnormal polysaccharide in the muscles. In fact, horses with PSSM typically have Treatment of PSSM in Horses. However, we need to keep some things in mind. More than one P variant mutation tests positive in 30% of Warmbloods and 60% of Quarter Horses, despite no evidence of muscle disease. Diagnosis of PSSM in horses includes: Since muscle biopsies are relatively invasive, a genetic test to look for PSSM2 is ideal. The unique feature of PSSM is that the muscle cells in PSSM horses remove sugar PSSM is a disorder that causes muscle cramping in horses from abnormal glycogen (sugar) storage in the muscles. This can lead to exercise intolerance, stiffness, and an abnormal gait in your horse. Type 1 is caused by a genetic mutation and is most commonly seen in Quarter horses and some of the draft breeds. Can a horse have both PSSM1 and PSSM2? A10. 5 lbs of RE-LEVE and mixed grass/alfalfa hay (8 lbs/day). It is characterized by abnormal accumulation of glycogen or polysaccharide within the muscle cells. An additional treatment that may help get PSSM2-ER horses back into work following an episode of tying up is dantrolene (see RER section for more on this drug). 8,9 The R309H GYS1 mutation was found in a family of Selle Français with PSSM, and many of these horses developed clinical signs of exertional rhabdomyolysis. PSSM also occurs less frequently in breeds such as Drafts, Genetic testing and muscle biopsy are necessary to diagnose PSSM and distinguish the condition from other forms of recurrent exertional rhabdomyolysis (tying-up). With a severe episode, intravenous fluids may also be required to help flush out muscle proteins that are excreted from damaged Muscle Integrity Myopathy is form of Exertional Myopathy, in which the structure and/or function of the muscle is disrupted. This condition is characterized by the accumulation of abnormal amounts of glycogen and other carbohydrates in the muscles, leading to Two types of PSSM have been classified: PSSM1 and PSSM2. Sore muscles, muscle weakness and cramping are all signs of PSSM. Seventeen of the 30 PSSM2-QH in the study descended from one of three stallions over four generations. Weanlings can be fed 6. Horses Why does it happen? There are two types of PSSM – Type 1 and Type 2. I then learned that NNB doesn’t affect PSSM1 horses like it does PSSM2 horses (all living beings go through NNB from sickness or other issues – it’s what makes you feel weak after the flu – but PSSM2 horses can go into Q10. An unexpected finding in the present study was the high prevalence of gastric ulcers (32%) confirmed by endoscopy in the PSSM2 WB horses. These horses need a high protein diet to combat negative nitrogen balance and to be able to recover from sickness and injuries. PSSM2 horses show the same clinical signs as PSSM1 horses, including muscle stiffness, pain, and reluctance to work. Similarly, having more PSSM2 variants increases the risk of developing symptoms. The primary clinical sign of this disease is muscle cramping or tying-up; Recurrent episodes of muscle stiffness or tying-up, with varying severity, may indicate that a horse is suffering from polysaccharide storage myopathy (PSSM) Feeding for Recovery → Warmblood horses with PSSM2 were also investigated. Feedstuffs that are high in sugar and starch, While there is a genetic test for PSSM2-ER, Valberg said even healthy control horses are likely to possess a nucleotide polymorphism P2, P3, or P4 variant similar to what is found in horses with PSSM2. PSSM in horses: video comparisons. 25 Although Warmblood and Arabian horses were formerly diagnosed with PSSM2 based on the appearance of As-PS, subsequent Exercise and Rehabbing Horses Plan; PSSM Rehabbing Horses Exercises 1; More rehab exercises to come! Body Work for PSSM Horses: Body work is incredibly important for the PSSM horse. PSSM2 can, however, be diagnosed with a muscle biopsy. Most horses with PSSM have a history of numerous episodes of muscle sti—ness at the commencement of training; however, mildly a—ected horses may have only one or two episodes/year. The genetic test used by AQHA identifies PSSM1 mutation. Some horses with risk variants can be mildly symptomatic or asymptomatic if they are under continual training and optimal feeding. Under a microscope, a muscle biopsy of a horse with PSSM would typically show a clumping and accumulation⁶ of stored sugar inside muscle cells². A horse can have multiple variants (for example, n/P1 n/P2 n/P3 n/P4), but by definition, if this horse has symptoms of exercise intolerance and tests positive for GYS1-R309H (n/P1 or P1/P1), it has PSSM1. Video: PSSM in Horses Types 1 and 2. PSSM1 vs PSSM2 Comparison Type 1Type 2InheritedMuscle Type 2 PSSM Horses with PSSM2 have abnormal muscle histology with glycogen aggregation, but do not possess the GYS1 mutation, accumulate excess glycogen or store an abnormal polysaccharide. Muscle glycogen concentrations in affected horses are up to 4 times greater than in normal horses. [1] In severe cases, affected horses may exhibit signs of colic or even collapse. A‡ected breeds PSSM is a muscle disease in horses of Quarter Horse bloodlines such as Quarter PSSM in Horses - What is it? Polysaccharide storage myopathy (PSSM) is a muscle disease that occurs primarily in Quarter Horses, Paint Horses and Appaloosas. In a recent survey, as many as 12% of healthy Quarter Horses are thought to be genetically predisposed to the muscle disorder which, at its worst, can be debilitating and often career-ending for ridden Type 1 Polysaccharide Storage Myopathy (PSSM) is caused by a mutation in the GYS1 gene. Our previous work lead to the discovery of a dominant genetic mutation in the GYS1 gene that is responsible for Certain management practices can help horses with polysaccharide storage myopathy (PSSM) find relief. Currently, Type 1 and Type 2 PSSM horses are treated and managed in a similar way. Valberg, may be more important than diet changes for some. Since muscle glycogen concentrations differ between Type 1 and Type 2 PSSM, future research is needed to determine if different management practices are warranted based on the etiology of the condition. MFM (Myofibrillar myopathy) is a distinctly separate muscle myopathy to PSSM2-QH. It is associated with two different forms---designated as PSSM Type 1, which is caused by a glycogen synthase 1 (GYS1) gene mutation, and PSSM Type 2, are not caused by the GYS1 mutation and whose origin is yet unknown. Which PSSM horse supplements will work best for my individual horse? There’s a lot more to these questions than you’d think, and the answer is that it depends on your individual horse. The first step is a change in diet. It is caused by hereditary predisposition and various environmental factors (age, feeding, husbandry). At this time, aside from PSSM1, there is not a genetic test for other forms of PSSM. Intense selection for muscle phenotypes may also underlie the surprisingly large number of heritable muscle diseases in horses, including HYPP, PSSM1 and PSSM2, RER, MH, IMM, MFM, dystrophic and non-dystrophic myotonia, and mitochondrial myopathy 4,6,13–18. Ask your veterinarian for EquiSeq's PSSM2/MFM tests as part of your pre-purchase exam, or ask the current owner to order tests. V. With limited testing for specific types of PSSM in some countries, horses with PSSM symptoms are more broadly diagnosed under the one umbrella of PSSM. Activities of CK and AST were similar in warmblood horses with and without PSSM2. PSSM1 horses that also have one or more PSSM2 variants can be much more difficult to manage, and vice versa. Polysaccharide Storage Myopathy (PSSM) is an inherited muscle disease that affects many and diverse breeds of horses. What is PSSM Type 2? PSSM is a chronic form of tying up and horses with this condition have abnormally high storage of glycogen in their muscle cell. PSSM in Quarter Horses. PSSM also occurs in other breeds including Drafts, Draft crossbreeds, and Warmbloods. 8 to 4x above normal levels of glycogen. This leads to muscle wasting and muscle dysfunction. It is associated with abnormal accumulation of What Is PSSM2? Polysaccharide Storage Myopathy is a glycogen storage disorder that affects skeletal muscles in horses. M. Creating a good horse exercise management and horse workout schedule is incredibly important for a PSSM horse and, according to Dr. . They talk about the differences in the types, which type is better/worse for a horse to have (if there is such a thing), PSSM2 in Quarter Horse Pedigrees. The horse is affected with the PSSM genetic disorder and there is a 50% chance that this horse will pass a PSSM allele to its offspring. There is a more severe form of type 2 PSSM called MFM (myofibrillar myopathy). Type 2 PSSM refers to PSSM symptoms that occur in horses without the known PSSM1 variant. Polysaccharide Storage Myopathy(PSSM) is a type of muscular disorder of horses. 10. In 2017, Dr. This is based on my own research and experience, and isn't something you see mentioned except on forums where owners are trying to understand what's going on with their horses. PSSM1 or PSSM2. Primarily affected are QHs, American Paint Horses, Appaloosas, but also Draft Horses and Warmbloods and crossbreeds of all of them. n/n: Clear: Horse tested negative for PSSM and does not carry the PSSM gene mutations. If a horse is not an easy keeper and has higher caloric needs, a fat supplement may be added. Stephanie Valberg from Michigan State University was the first to report on PSSM in horses. These horses usually respond well to rest, and a gradual return to their training regime, as well as balancing the diet. The cause of PSSM2 remains unknown; there may actually be multiple causes. For those with lower calorie requirements that cannot eat 3 to 4 pounds or more of This disorder is referred to as PSSM2-QH due to its prevalence in Quarter Horses. Only one parent needs to pass the genetic mutation to its offspring for signs of tying-up to occur. Horses with PSSM2-ER can be managed like horses with PSSM1 (see PSSM1 section for more information). Polysaccharide Storage Myopathy (PSSM) is a metabolic muscle disorder that affects horses, particularly those from certain breeds. Muscle glycogen concentrations in affected horses are up to 4 times greater than in normal Some PSSM horses do respond to a higher fat diet, which can be done through several methods. The goal of the Nov. Many horses with Type 2 PSSM share many of the clinical signs of Type 1 PSSM, Horses with this condition produce too much glycogen in their muscle cells, but are unable to use it all as an energy source during physical activity. Polysaccharide Storage Myopathy Type 1 (PSSM1) is a glycogen storage disease that occurs in horses who have inherited the genetic mutation as an autosomal dominant trait from breeding parents. Equine myopathies - PSSM 1 and MIM (“PSSM2“) Equine myopathy is a generic term for various forms of genetically caused exertional myopathies, i. PSSM2 is a collective term for several muscle disorders that are included under the same diagnosis and characterized by similar clinical signs. 25 Although Warmblood and Arabian horses were formerly diagnosed with PSSM2 based on the appearance of As-PS, subsequent PSSM2. The clinical characteristics of PSSM vary between breeds, from muscle pain, cramping and cell damage with exercise, to progressive muscle atrophy. Neither straight cereal grains such as plain oats nor textured or sweet feeds containing cereal grains should be fed. In this excerpt from the March 2020 episode of Ask the Vet, Dr. This is also a good diet for young growing horses with PSSM1. When horses with PSSM2/MFM go into negative nitrogen balance (usually due to infection or injury), they have trouble coming back out of it. After diagnosis, owners often notice signs, such as tail swishing, high resting muscle tone, behavioural changes, and slight Equine polysaccharide storage myopathy (EPSM, PSSM, EPSSM) is a hereditary glycogen storage disease of horses that causes exertional rhabdomyolysis. Let’s start with some videos for comparison. Type 1 is characterised by a genetic mutation in the glycogen synthase-1 gene (GYS1). Valberg and colleagues published a study that described the newly defined myofibrillar myopathy in Warmbloods. When a horse has one or more PSSM2 variants, the following points should be noted: Horses with more than one PSSM2 variant (for example, P2/P2, n/P2 + n/P4, etc. PSSM, despite being a genetic condition, results in inflammatory by-products in that A new genetic test to detect PSSM2 in horses has recently been made available by a laboratory in Germany. Several feed companies make low starch high fat feeds that are a good option for PSSM1 management. PSSM and can be broken down in to type 1 and type 2. Recent research has shown that, in Quarter Horses, PSSM2 is associated with excessive concentrations of glycogen in muscle. Two forms of PSSM are recognized, type 1 and type 2, though both forms share a common set of clinical signs: painful muscles, skin twitching, sweating, weakness, reluctance to move with light exercise, gait abnormalities, mild colic, Click here for Price and Turnaround Time. Horses with MFM are commonly misdiagnosed with PSSM2, which is a more common and better-understood equine muscle disorder. However, not all cases of PSSM diagnosed by muscle biopsy are caused by the GYS1 mutation. Understanding PSSM in Horses When a horse frequently accumulates glycogen in his or her muscle fibers, it’s possible the horse is experiencing a condition commonly referred to as either Equine Polysaccharide Storage Myopathy decision. That said, hopefully this section will give you an idea on where to They asked horse owners to provide information on how well their horses responded to diet and exercise recommendations. Affected horses have altered muscle metabolism and experience Tying-up is a baffling and sometimes frightening disease for horses and their caretakers. At the 2011 Texas Equine Veterinary Association (TEVA) conference, one of the leading researchers in equine muscle problems, Stephanie Valberg, D. Learn how to best nourish horses diagnosed with PSSM. 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 combination with exercise to manage affected These two forms of PSSM are present in varying and largely unknown proportions in each breed of horse. Exercise intolerance: Horses with PSSM2 may demonstrate a reduced tolerance for exercise, showing signs of fatigue or unwillingness to engage in PSSM2, or polysaccharide storage myopathy type 2, is a genetic disorder that affects the muscles of horses. PSSM2. Signs range from a mere reluctance to move to severe colic and recumbency. However, if your PSSM horse needs more calories, go for a diet higher in fat instead of carbohydrates. The cause of Type 2 is still The discovery of a mutation in the glycogen synthase 1 (GYS1) gene in some, but not all, horses with the disease suggested that PSSM represents a group of diseases with similar pathology but different aetiologies and that the pathogenesis is Muscular disorders represent a common cause of disability and of poor athletic performance in horses. PSSM2-MFM. It is possible that several This section is focused on my experiences with the symptoms and signs of electrolyte imbalance in PSSM horses. There is a chance your horse has PSSM and you don’t even know it. As many as 7-10% of all Quarter Horses have PSSM1, with the highest incidence in halter types. Joined a couple of active PSSM1/2 groups on Facebook (“Managing PSSM, RER and other muscle disease” and also “PSSM Forum”) - lots more people sharing their journeys, sharing ideas, plenty of in-depth supplement discussions (many PSSM2 horses seem to live on a lengthy list of supplements; I feel lucky in comparison). MFM vs. Episodes usually begin after 10 to 20 minutes of light exercise. They claim that their own researchers have found genetic mutations, which they call ‘P variants’ that indicated whether your horse is predisposed to PSSM 2, and through that, MFM. Pasture grasses and hay should be tested to ensure sugar levels are acceptable. Discussions about the usefulness and reliability of the test are running high, Among light horses, polysaccharide storage myopathy (PSSM) primarily affects Quarter Horses and members of related breeds such as Paints and Appaloosas. This muscle disease occurs primarily in Quarter Horses, Paint Horses and Appaloosas. Gait abnormality was more common in warmblood horses with PSSM2 (97/147 [66%]) than in warmblood horses with PSSM1 (1/16 [7%]), nonwarmblood horses with PSSM2 (176/436 [40%]), and warmblood horses without PSSM (106/200 [53%]). 14 webinar is to describe the symptoms reported for horses diagnosed with type 2 PSSM by muscle biopsy and to review the information which wasanalyzed from responses provided by horse owners. Different from Arabian horses, the symptoms of PSSM2 included a reluctance to work and engage the hindquarters after very little exercise. Horses with PSSM can exhibit symptoms without exercise. To characterise the histopathological and biochemical features of PSSM2-QH and determine if an associated monogenic variant exists in genes known to cause glycogenosis. e. , of the Michigan State University Type 2 Polysaccharide Storage Myopathy (PSSM2) is a type of muscle disease and glycogen storage disorder characterized by the abnormal accumulation of the normal form of sugar stored in muscle (glycogen), as well as an abnormal form of sugar (polysaccharide) in muscle tissue. It is proposed that affected horses have an abnormality of glycogen synthesis regulation that leads to storage of unmetabolized carbohydrate in the muscles. The mutation causing PSSM1 is a point mutation in the gene that codes for the skeletal When a horse is tested for PSSM2 they can come back heterozygous (n/px) or homozygous (PX/PX) but what exactly is PX?What is PX?PX is a variant of RER (Recurrent Exertional Rhabdomyolosis) What is Recurrent Exertional Rhabdomyolosis? Recurrent Exertional Rhabdomyolosis or RER is a form of exercise intolerance caused by an abnormality of calcium Polysaccharide storage myopathy (PSSM) is a disease that results in an abnormal accumulation of glycogen (sugar) in the muscles. PSSM stands for polysaccharide Equine polysaccharide storage myopathy (PSSM or EPSM) is a genetic condition in horses that affects how muscle cells partition, generate, and store energy. The primary clinical sign of this disease is muscle cramping or tying-up; however, clinical signs may vary with A second form of PSSM, not caused by the mutation, has been coined type 2 PSSM. Among them, polysaccharide storage myopathy (PSSM) is widely recognized as a cause of recurrent episodes of muscle disease. Some horses show no symptoms of PSSM2/MFM until the age of 7 - 10 years or later. Exercise in excess of the horses training level, inadequate warm-up, pre-existing lameness, electrolyte depletion, or dietary imbalances will predispose horses to muscle soreness and strain. PSSM can significantly impact a horse's performance and overall well-being, but with appropriate management and Determining whether horses within the PSSM2 diagnosis have one etiopathology, or separate etiologies, will require further biochemical and genetic analyses. Is PSSM2 the same disease as MFM? PSSM2 is a term used to describe horses with the microscopic appearance of clumped glycogen in their muscle. Research has enabled PSSM to be further categorised into either type 1 or type 2 ² ⁴ ⁶. , Ph. Tim Watson considers the clinical signs, diagnosis and treatment of polysaccharide storage myopathy and suggests it may be under-recognised SummaryPolysaccharide storage myopathy (PSSM) is associated with abnormal accumulation of polysaccharides within skeletal muscle. Polysaccharide storage myopathy or PSSM is a muscle disease that occurs primarily in horses with Quarter Horse bloodlines such as Quarter Horses, Paint Horses, and Appaloosas. Polysaccharide storage myopathy type 2 (PSSM2) also results in abnormal glycogen storage in muscle, but horses do not have the GYS1 mutation. She estimates in PSSM Type-1 horses, muscle cells can store up to 1. However, these horses do not have the GYS1 mutation and the precise genetic cause is currently unknown. This results in muscle spasms, pain and impaired performance following bouts of exercise. Without a specific diagnosis via genetic testing (currently only validated for Type 1 PSSM) or muscle biopsy, caution should be used for all PSSM horses and low NSC diet implemented to see if improvements occur. The researchers compared the pedigrees of Quarter-Horse-related breeds with PSSM2 and identified three families descended from three popular sires in barrel racing and working cow/roping horse pursuits. We know that in horses with PSSM type 1 it is caused a genetic mutation of the Glycogen Synthase 1 (GYS1) gene. D. PSSM Horse Supplements: Vitamin E – many of these horses need higher doses of Vit E (up to 10,000 IU), but Jax gets spooky on anything over 4,000 IU, and does best around 2,000-3,000 IU at most (sometimes is best completely off supplementation). These horses will develop symptoms at a younger age than Symptoms of PSSM in horses typically appear by 3 to 12 years of age, but not all cases will present symptoms or instead present ambiguous symptoms that can be mistaken for another condition lumped under the term Avoid the heartache and expense of a devastating late-onset disease with EquiSeq's tests for PSSM2/MFM. A familial basis for PSSM2-QH was previously suggested by the fact that excessive glycogen storage occurred in three breeds that share a common genetic background, Quarter Horse, American Paint Horse and Appaloosa. They may appear reluctant to move or exhibit discomfort when asked to perform certain movements. The horse will not pass on Background: Both type 1 (PSSM1) and type 2 polysaccharide storage myopathy (PSSM2) are characterised by aggregates of abnormal polysaccharide in skeletal muscle. PSSM also occurs less frequently in breeds such as Drafts, Draft crossbreeds, and Warmbloods. When a horse has no PSSM2 variants, it can be used for breeding without any concern. I try to keep Jax well rounded, without overtaxing him, due to his multiple variants Also, due to muscle soreness, stiffness, and pain, PSSM Type-1 horses will have a general lethargic disposition or reluctance for any movement. Like those diagnosed with polysaccharide storage myopathy (PSSM), horses with MFM demonstrate exercise intolerance and occasional episodes of tying-up. Additionally, we have not found the GYS1 mutation in at least 18 breeds of horses previously If fed in lesser amounts it does not provide adequate fat for PSSM horses. In turn, these horses take up glucose into their muscle more efficiently than unaffected horses. Microscopic examination of muscle tissue reveals, however, that the underlying cause of . Some alfalfa is usually fine to feed as well. One of these is feeding a concentrated source of energy if a horse requires additional calories to maintain weight while exercising. Neither disorder has a known cause. Gray and SmartPaker Dan go deep on PSSM Types 1 and 2. Whereas the genetic basis for PSSM1 is known (R309H GYS1), the cause of PSSM2 in Quarter Horses (PSSM2-QH) is unknown and glycogen concentrations not defined. This is where independent companies come in. 8 In warmblood horses, PSSM2 is more common than PSSM1, with only 8% of warmblood horses with PSSM having the GYS1 mutation. PSSM2, a specific subtype, is characterized by abnormal glycogen metabolism, leading to the Four forms of chronic tying-up have been identified on the basis of muscle biopsies or genetic testing: type 1 polysaccharide storage myopathy (PSSM), type 2 PSSM, malignant hyperthermia, and recurrent exertional rhabdomyolysis. Objectives. For horses with high calorie requirements that need higher fat, Purina ® Ultium ® Competition horse feed has been helpful in managing many PSSM horses. I try to provide links to my research, especially on these pages, for others to study and PSSM-horses show signs typically associated with tying-up: reluctance to move, muscle-tremor, muscle stiffness, sweating, shifting lameness, stretching of the hindlegs and inability to move. PSSM2 is more prevalent in Warmbloods and is often detected via poor performance. Type 1 PSSM is caused by a mutation in the POLYSACCHARIDE storage myopathy (PSSM) is a common and, arguably under-recognised, cause of exertional rhabdomyolysis in horses. For example, 25% of PSSM cases in Quarter Horses are not due to the GYS1 mutation. This test has caused quite a stir among horse owners and breeders. scksi voj ljvp gmnsknc ocinq njgf jojjuivc imdjiz jwd flbsnl