Systemic calcinosis in horses: Pathological and genetic aspects.

Area of Science:

• Veterinary Pathology
• Equine Medicine
• Molecular Genetics

Background:

• Systemic calcinosis is a rare equine syndrome characterized by muscle lesions and mineralization.
• The molecular and histopathological aspects of this condition remain poorly understood.
• This study investigates systemic calcinosis in horses in Brazil.

Purpose of the Study:

• To describe the epidemiological, pathological, and molecular features of systemic calcinosis in horses.
• To investigate potential genetic and infectious triggers for the condition.
• To contribute to a better understanding of this rare equine disease.

Main Methods:

• A retrospective exploratory study of six necropsied horses.
• Review of post-mortem records, followed by histopathology, immunohistochemistry, microbiology, and molecular investigation.
• PCR testing for the E321G MYH1 gene variant and immunostaining for Streptococcus equi.

Main Results:

• Affected horses were young Quarter Horses with acute disease progression.
• Muscle necrosis and mononuclear infiltration were observed with mineral deposition in muscles and other organs.
• The E321G MYH1 gene variant was detected in 5/6 horses, and Streptococcus equi in 3/6 horses.

Conclusions:

• Systemic calcinosis in horses involves immune-mediated muscle lesions and organ calcification.
• The E321G MYH1 gene variant may play a role in the pathophysiology of systemic calcinosis.
• Limitations include small sample size and lack of pre-mortem data.