Genetic basis of DEB in Golden Retrievers - is caused by a point mutation in the COL7A1 gene, specifically the G1906S mutation. COL7A1 encodes type VII collagen, a key structural protein at the dermal-epidermal junction, providing skin stability. The mutation substitutes glycine with serine at amino acid position 1906, leading to defective anchoring fibrils. Inherited in an autosomal recessive manner. Affected dogs have two copies of the mutated gene, carriers have one copy, usually asymptomatic.
Pathophysiology - Mutation causes defective anchoring fibrils at the dermal-epidermal junction. Leads to skin fragility, blistering, erosions, and ulcers even with minor trauma. Lesions affect areas prone to friction or pressure: feet, face, genital areas, ears, and mucous membranes including mouth and esophagus. Blistering of skin tends to lessen by 8 months, but mucous membrane ulcers can persist into adulthood
Complications - Chronic painful skin ulcerations with risk of secondary infection. Impaired mobility due to painful foot and joint lesions. Feeding difficulties and aspiration pneumonia due to mucosal ulcers. Progressive disease often requires euthanasia in severe cases.
Clinical Presentation - Symptoms are usually apparent at birth or shortly after. Affected puppies may have blisters, ulcers, and erosions on the skin and mucosa. Growth retardation and smaller size may be noted due to feeding difficulties. Nail dystrophy and milia are common. Oral and esophageal lesions cause difficulty eating and swallowing, increasing aspiration risk.
Inheritance - Autosomal recessive inheritance requires both parents to be carriers to produce affected puppies. Carriers typically do not show symptoms but can transmit the gene mutation.
Why This Matters to Breeders and Vets - DEB severely impacts the quality of life due to painful skin and mucosal lesions. Genetic testing enables breeders to identify carriers and avoid producing affected dogs. The Golden Retriever form is a useful animal model for human DEB and gene therapy research.
