Amylopectinosis in fetal and neonatal Quarter Horses.
Abstract: Three Quarter Horses, a stillborn filly (horse No. 1), a female fetus aborted at approximately 6 months of gestation (horse No. 2), and a 1-month-old colt that had been weak at birth (horse No. 3), had myopathy characterized histologically by large spherical or ovoid inclusions in skeletal and cardiac myofibers. Smaller inclusions were also found in brain and spinal cord and in some cells of all other tissues examined. These inclusions were basophilic, red-purple after staining with periodic acid-Schiff (both before and after digestion with diastase), and moderately dark blue after staining with toluidine blue. The inclusions did not react when stained with Congo red. Staining with iodine ranged from pale blue to black. Their ultrastructural appearance varied from amorphous to somewhat filamentous. On the basis of staining characteristics and diastase resistance, we concluded that these inclusions contained amylopectin. A distinctly different kind of inclusion material was also present in skeletal muscle and tongue of horse Nos. 1 and 3. These inclusions were crystalline with a sharply defined ultrastructural periodicity. The crystals were eosinophilic and very dark blue when stained with toluidine blue but did not stain with iodine. Crystals sometimes occurred freely within the myofibers but more often were encased by deposits of amylopectin. This combination of histologic and ultrastructural features characterizes a previously unreported storage disease in fetal and neonatal Quarter Horses, with findings similar to those of glycogen storage disease type IV. We speculate that a severe inherited loss of glycogen brancher enzyme activity may be responsible for these findings. The relation of amylopectinosis to the death of the foals is unknown.
Publication Date: 1999-03-31 PubMed ID: 10098645DOI: 10.1354/vp.36-2-157Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This research reports a previously unidentified storage disease in fetal and neonatal Quarter Horses, yielding symptoms similar to glycogen storage disease type IV. The illness is characterized by inclusions in various tissue types believed to contain amylopectin, suggesting a possible severe inherited deficiency in glycogen brancher enzyme activity.
Study Overview
- Three Quarter Horses were examined in this research each displaying a myopathy characterized by large spherical or ovoid inclusions in skeletal and cardiac muscle fibers.
- The subjects were a stillborn female horse (horse #1), a six-month-old aborted female fetus (horse #2), and a one-month-old colt that had been weak from birth (horse #3).
- Smaller inclusions were also found in the brain, spinal cord, and some cells of all other tissues examined.
Diagnostic Findings
- The tissue inclusions were basophilic, staining red-purple with periodic acid-Schiff (both before and after digestion with diastase), and a moderately dark blue after toluidine blue staining.
- The inclusions did not react when stained with Congo red.
- Staining with iodine ranged from pale blue to black, while their ultrastructural appearance varied from amorphous to somewhat filamentous.
- These staining characteristics and resistance to diastase led the researchers to conclude that the inclusions contained amylopectin, a type of complex carbohydrate.
- A distinctly different kind of inclusion material was also present in the skeletal muscle and tongue of horse Nos. 1 and 3. These inclusions were crystalline with a sharply defined ultrastructural periodicity. These crystals did not stain with iodine and were often encased by deposits of amylopectin.
Hypothesis and Related Considerations
- Based on these findings, researchers suggest that the disease may be due to a severe inherited loss of glycogen brancher enzyme activity. This enzyme is crucial for the formation of glycogen used by the body for energy storage.
- The disease’s resemblance to glycogen storage disease type IV, a known genetic disorder that prevents the body from properly utilizing glycogen, further supports this hypothesis.
- The exact relationship of amylopectinosis to the death of the foals remains unknown, and further research is required to understand any causative relationships or treatment options.
Cite This Article
APA
Render JA, Common RS, Kennedy FA, Jones MZ, Fyfe JC.
(1999).
Amylopectinosis in fetal and neonatal Quarter Horses.
Vet Pathol, 36(2), 157-160.
https://doi.org/10.1354/vp.36-2-157 Publication
Researcher Affiliations
- Veterinary Medical Center, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA. render@ahdlms.cvm.msu.edu
MeSH Terms
- Amylopectin / chemistry
- Animals
- Animals, Newborn
- Coloring Agents / chemistry
- Congo Red / chemistry
- Female
- Fetal Diseases / embryology
- Fetal Diseases / genetics
- Fetal Diseases / pathology
- Fetal Diseases / veterinary
- Glycogen Storage Disease Type IV / embryology
- Glycogen Storage Disease Type IV / genetics
- Glycogen Storage Disease Type IV / pathology
- Glycogen Storage Disease Type IV / veterinary
- Horse Diseases / embryology
- Horse Diseases / genetics
- Horse Diseases / pathology
- Horses
- Inclusion Bodies / pathology
- Inclusion Bodies / ultrastructure
- Iodine / chemistry
- Male
- Microscopy, Electron / veterinary
- Muscle, Skeletal / embryology
- Muscle, Skeletal / pathology
- Muscle, Skeletal / ultrastructure
- Periodic Acid-Schiff Reaction / veterinary
Grant Funding
- NIH-NS16886 / NINDS NIH HHS
Citations
This article has been cited 5 times.- Brosnahan MM, Brooks SA, Antczak DF. Equine clinical genomics: A clinician's primer. Equine Vet J 2010 Oct;42(7):658-70.
- Fyfe JC, Kurzhals RL, Hawkins MG, Wang P, Yuhki N, Giger U, Van Winkle TJ, Haskins ME, Patterson DF, Henthorn PS. A complex rearrangement in GBE1 causes both perinatal hypoglycemic collapse and late-juvenile-onset neuromuscular degeneration in glycogen storage disease type IV of Norwegian forest cats. Mol Genet Metab 2007 Apr;90(4):383-92.
- Ward TL, Valberg SJ, Adelson DL, Abbey CA, Binns MM, Mickelson JR. Glycogen branching enzyme (GBE1) mutation causing equine glycogen storage disease IV. Mamm Genome 2004 Jul;15(7):570-7.
- Pasolini MP, Auletta L, De Biase D, Vaccaro E, Del Prete C, Montano C, de Chiara M, Di Napoli E, Paciello O, Piegari G. Clinical and Pathological Features of Flexural Deformities Associated with Myopathies in Foals. Vet Sci 2025 Jun 6;12(6).
- Koeberl DD, Koch RL, Lim JA, Brooks ED, Arnson BD, Sun B, Kishnani PS. Gene therapy for glycogen storage diseases. J Inherit Metab Dis 2024 Jan;47(1):93-118.
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