Myopathy with central cores in a foal

Area of Science:

• Veterinary Pathology
• Equine Myopathies
• Congenital Myopathies

Background:

• Central core disease is a congenital myopathy characterized by hypotonia and muscle weakness.
• Histological hallmarks include central cores lacking oxidative enzyme activity due to mitochondrial absence.

Observation:

• A 10-month-old pony foal presented with congenital hypotonia, stiff gait, limb contractures, and hoof deformities.
• Elevated muscle enzymes (creatine kinase, lactate dehydrogenase, aspartate transaminase) indicated muscle disease.

Findings:

• Muscle biopsy revealed central cores devoid of oxidative enzyme activity (cytochrome oxidase, succinate dehydrogenase, NADH tetrazolium reductase).
• Immunohistochemistry showed a desmin network within these cores.
• Ultrastructural examination confirmed preserved sarcomeres with irregular Z-lines and a lack of mitochondria within the central cores.

Implications:

• This case confirms central core disease in a pony foal, expanding the understanding of its occurrence in non-equine species.
• The findings highlight the utility of specific enzyme histochemistry and immunohistochemistry in diagnosing equine myopathies.
• Further research may elucidate genetic underpinnings and therapeutic strategies for congenital myopathies in animals.