Koko Genetics

Dogs that experience dystrophic epidermolysis bullosa often develop blisters in areas of increased friction or trauma, such as the paw pads, face, ears, mouth and genital area. If the condition is mild, blisters appear occasionally, whereas, if the EAD is severe, in addition to blisters, erosive ulcers also appear in the aforementioned areas.

Symptoms

Dogs that experience dystrophic epidermolysis bullosa often develop blisters in areas of increased friction or trauma, such as the paw pads, face, ears, mouth and genital area. If the condition is mild, blisters appear occasionally, whereas, if the EAD is severe, in addition to blisters, erosive ulcers also appear in the aforementioned areas.

Disease Management

There is no treatment to prevent the onset of the disease, but measures can be taken to help create a safe and protected environment for the dog by avoiding objects or surfaces that may cause skin lesions. Also, immunosuppressive drugs such as prednisone and corticosteroids help to control the symptoms.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

The COL7A1 gene encodes type VII collagen, which is the main component of the fibrils responsible for anchoring the epidermis to the underlying dermis. Mutations in the COL7A1 gene can produce defective type VII collagen, resulting in skin disorders such as dystrophic epidermolysis bullosa. In the Golden Retriever breed, the c.5716G>A variant has been identified, which consists of a nonsense mutation causing a glycine to serine substitution at position 1906 of the encoded protein. The described variant deletes a restriction site for Hae III endonuclease. The Golden Retrievers studied suffered from a mild form of EAD.

Most affected breeds

Golden Retriever

Bibliography

Baldeschi C, Gache Y, Rattenholl A,et al. Genetic correction of canine dystrophic epidermolysis bullosa mediated by retroviral vectors. Hum Mol Genet. 2003 Aug 1;12(15):1897-905.

Dystrophic Epidermolysis Bullosa (COL7A1 gene, Golden Retriever)