Genetic basis - caused by a heterozygous mutation in the COL5A1 gene, specifically a frameshift deletion c.3038delG leading to p.Gly1013ValfsTer260. COL5A1 encodes the α1 chain of type V collagen, which regulates collagen fibril formation essential for connective tissue strength. The mutation produces a truncated, non-functional protein resulting in collagen V haploinsufficiency and disrupts normal collagen fibrillogenesis.
Pathophysiology - Loss of functional collagen V results in abnormal collagen fibril formation, causing weakened connective tissue. Clinical signs stem from fragile skin and hypermobile joints due to compromised structural integrity. Mutant collagen may form improperly leading to intracellular stress and disrupted extracellular matrix.
Complications - Fragile skin leading to frequent wounds and infections. Joint pain and damage due to hypermobility. Possible chronic disability and reduced quality of life. No cure; management is supportive and preventive.
Why This Matters to Breeders and Vets - The autosomal dominant nature means affected dogs and carriers cannot be distinguished without genetic testing. Breeding an affected dog or carrier can produce multiple puppies with this severe connective tissue disorder. Genetic testing identifies carriers, helping breeders avoid affected litters and reduce disease prevalence. Veterinarians can use genetic information for accurate diagnosis, prognosis, and advising owners on management. Awareness helps prevent misdiagnosis and unnecessary treatments by understanding the genetic and clinical basis.