Glycogen storage disease, type II

Disease overview

Glycogen Storage Disease Type II (GSD-II) is a genetic disease that changes the way the body stores and uses the form of sugar called glycogen. A mutation in a gene results in an insufficient amount of an enzyme that is needed for breaking apart glycogen into glucose so that it can be used as a primary source of energy by the body. Glycogen buildup occurs, which affects the ability of the organs in the body to properly function. This form of GSD leads to a dilated esophagus as well as an enlarged heart.

Gene name

GAA

Inheritance

Autosomal recessive

Signs and symptoms

Dogs with GSD-II typically present with clinical signs around 6 months of age. The disease rapidly progresses, leading to death around one to two years of age. Symptoms include cardiac abnormalities, weight loss, and regurgitation/vomiting. Respiratory distress may be apparent as a result of heart failure, and/or enlargement of the esophagus, which as a result loses its ability to move food into the stomach (megaesophagus).

How is it diagnosed

A veterinarian will review health history, conduct a thorough exam, and note any clinical signs. Laboratory tests and imaging of the heart and esophagus may be indicated to determine a diagnosis. Genetic testing assists veterinarians with diagnosis and helps breeders identify affected and carrier dogs.

Breeds at higher risk

Finnish Lapphund, Swedish Lapphund

Citations

Seppälä EH, Reuser AJ, Lohi H. A nonsense mutation in the acid α-glucosidase gene causes Pompe disease in Finnish and Swedish Lapphunds. PLoS One. 2013;8(2):e56825. doi: 10.1371/journal.pone.0056825. Epub 2013 Feb 14. PMID: 23457621; PMCID: PMC3573005.

Almodóvar-Payá A, Villarreal-Salazar M, de Luna N, Nogales-Gadea G, Real-Martínez A, Andreu AL, Martín MA, Arenas J, Lucia A, Vissing J, Krag T, Pinós T. Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models. Int J Mol Sci. 2020 Dec 17;21(24):9621. doi: 10.3390/ijms21249621. PMID: 33348688; PMCID: PMC7766110.