Genetic basis - caused by variants in the COL5A1 gene, which encodes the α1 chain of type V collagen, essential for collagen fibril formation. Two distinct variants have been identified in Labradors; Variant 2 specifically is a frameshift deletion mutation c.3038delG (p.Gly1013ValfsTer260). This mutation leads to truncated collagen V protein and haploinsufficiency, disrupting normal collagen assembly and connective tissue strength.
Pathophysiology - The defective COL5A1 results in abnormal collagen fibrils, leading to weakened skin, hyperextensibility, and fragile connective tissue. Symptoms emerge from structural defects in skin and joint collagen fibers, causing fragility and hypermobility.
Complications - Fragile skin prone to injury and slow healing. Joint problems causing chronic discomfort and mobility issues. Possible euthanasia for severely affected dogs. No cure; management is supportive.
Why This Matters to Breeders and Vets - Identifying the COL5A1 variant enables precise diagnosis and prevention of affected litters through genetic testing. Breeders can avoid breeding carriers or affected dogs to reduce disease incidence. Veterinarians benefit from understanding the genetic basis, allowing better clinical management and owner counseling. Early diagnosis prevents mismanagement and focuses on supportive care. Helps in maintaining healthier breed populations by reducing inherited connective tissue disorders.