First report of junctional epidermolysis bullosa (JEB) in the Italian draft horse.

The research identifies the first case of junctional epidermolysis bullosa (JEB), a skin disorder, in an Italian draft horse. It mentions that the disease may have origins in mutations in the LAMC2 gene, and its identification can prevent future economic loss in horse breeding.

Study Background

• Epitheliogenesis imperfecta, a skin disorder in horses, was first characterized in the early 20th century.
• The disease was thought to come from a genetic cause with an inherited autosomal recessive pattern.
• Early studies using electron microscopy determined that the lesions were due to defects in the lamina propria, and the condition was reclassified as epidermolysis bullosa.
• Two mutations were identified later in genetics studies as being key contributors to the disease: an insertion in LAMC2 in Belgian and other draft horses, and a large deletion in LAMA3 in the American Saddlebred horse.

Research Methodology

• The researchers studied a newborn Italian draft horse foal, which presented with signs of a mechanobullous disease, including multiple erosions and ulcerations on the distal extremities.
• A histological examination of skin biopsies from the foal showed the formation of a subepidermal cleft, while transmission electron microscopy evidenced that the lamina densa of the basement membrane remained attached to the dermis.
• With the aid of genetic tests, the researchers confirmed the presence of the 1368insC mutation in the LAMC2 gene in both the foal and its relatives, thereby diagnosing the foal with JEB.

Study Findings and Results

• This study marks the first reported case of JEB in Italy.
• The disease was characterized by typical macroscopic, histologic, and ultrastructural findings, all pointing out to a mutation in the LAMC2 gene.
• Further tests are required to investigate whether this mutation is present in the broader Italian draft horse population, which is currently considered to be at low frequency.
• The study suggests that in this case, non-standard breeding practices acted as an odds enhancer for unfavorable alleles, further emphasizing the importance of maintaining breeding standards.

Significance and Impact

• This study has significant implications for the horse breeding industry. Identifying carriers of the gene mutation is necessary to prevent economic loss and ensuring the health and well-being of the horses.
• The study contributes to the body of knowledge on JEB, its genetic origins, and the factors that can contribute to its manifestation in horses.