Glycogen Storage Disease (Glycogenosis) in Cats What To Know About Glycogenosis In Cats and How To Prevent It

Glycogen Storage Disease (Glycogenosis) in Cats

Cats with the rare hereditary condition known as glycogenosis experience an abnormal buildup of glycogen in their tissues. We discuss this disorder extensively in this article.

What is Feline Glycogenosis?

Glycogenosis is a rare genetic disorder that affects cats, causing an abnormal accumulation of glycogen in their tissues. This condition can lead to a range of symptoms, including lethargy, weakness, and difficulty maintaining weight. Glycogenosis has no known treatment. However, early diagnosis and care of the ailment can significantly increase a cat's quality of life.

In this article, we'll look at the causes, signs, diagnoses, and available treatments for cat glycogenosis. We'll also offer some advice on how to handle this disease in your feline friend.

What is Enzyme Deficiency?

When a cat's body is unable to generate or utilize a specific enzyme needed for normal metabolic activities, it is said that the cat has an enzyme deficiency. Enzymes are necessary proteins that catalyze chemical reactions in the body, and a lack of them can result in a variety of health issues.

Types of Glycogenosis In  Cats

Glycogen is also known as animal starch, and several different types of glycogenosis have been identified in cats. The numerous forms are distinguished by the precise genetic mutation that causes the illness and the enzyme that is affected.

  • Type 1 glycogen storage disease: Also known as von Gierke disease, a lack of the enzyme glucose-6-phosphatase causes this. This enzyme is in charge of turning glycogen that has been stored into glucose so that the body can utilize it as fuel. Lack of glucose-6-phosphatase results in the buildup of glycogen in the liver, which manifests as tiredness, weakness, and an enlarged liver.

  • Type 2 glycogen storage disease: Commonly known as Pompe disease, this kind of glycogenosis is characterized by a lack of the enzyme acid alpha-glucosidase. Inside the lysosomes of cells, this enzyme is in charge of converting glycogen to glucose. Glycogen builds up in the lysosomes in the absence of this enzyme, weakening muscles and impairing breathing.

  • Type 3 glycogen storage disease: This kind of glycogenosis, also known as Cori sickness, is brought on by a lack of the enzyme responsible for debranching glycogen. This enzyme converts glycogen stored in the liver and muscles into glucose. When this enzyme is lacking, glycogen builds up in the liver and results in an enlarged liver, hypoglycemia, and weakening of the muscles.

  • Type 4 glycogen storage disease: Glycogen storage disease type 4, also called Andersen disease, a deficiency in the enzyme glycogen branching enzyme causes this type of glycogenosis. This enzyme is in charge of branching glycogen molecules, which is required for its correct breakdown and usage. Glycogen builds up in the liver when this enzyme is lacking, leading to an enlarged liver, liver failure, and gastrointestinal issues.

  • Type 7 glycogen storage disease: This kind of glycogenosis, also called Tarui disease, is brought on by phosphofructokinase deficiency. During exercise, this enzyme is in charge of destroying the glycogen stored in the muscles. When this enzyme is lacking, glycogen builds up in the muscles and causes weakness, cramping, and exercise intolerance.


Cats with glycogenosis are affected by a genetic defect that affects the enzymes needed to break down glycogen, a complex sugar molecule the body needs as fuel. Specifically, glycogenosis in cats is typically caused by a deficiency in the enzyme glycogen branching enzyme (GBE), which is essential for the normal breakdown and utilization of glycogen in the body.

Without GBE, glycogen builds up in the liver and other tissues, which can result in several health complications. Due to the autosomal recessive nature of the condition's inheritance, a cat has to inherit two copies of the defective gene—one from each parent—to be affected. Even while carriers of the defective gene may not experience any symptoms, they can transfer the condition to their children.


The clinical signs of glycogen degeneration in cats can vary depending on the type of the condition, the gravity of the disease, and the age of onset. However, there are known symptoms that can indicate the presence of glycogenosis in cats. These symptoms include:

  • Lethargy and weakness

  • Appetite loss

  • Enlarged liver (hepatomegaly)

  • Gastrointestinal problems like vomiting and diarrhea

  • Hypoglycemia (low blood sugar)

  • Muscle weakness and cramping

  • Exercise intolerance

  • Respiratory problems 

  • Jaundice

  • Neurological problems, such as seizures and disorientation.

Treatment and Management

The therapy and management options for glycogenosis may differ depending on the specific cause, the severity of the disease, and the age of onset. The following are some typical methods for treating and controlling feline glycogenosis:

In summary, while glycogenosis in cats cannot be completely avoided, genetic testing, responsible breeding, early detection and management, diet management, regular exercise, and avoidance of stressors can help to reduce the possibility of cats developing the condition.

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