Dermal pathology in a Catahoula Leopard dog with Dermasparaxis Ehlers Danlos syndrome caused by a homozygous ADAMTS2 missense variant.

Dermatosparaxis is a subtype of Ehlers-Danlos syndrome (dEDS) that typically results in euthanasia of dogs in the first several months of life because of complications mostly related to extreme skin fragility. The goal of this report was to describe ultrastructural features of collagen fibrils from a dog with a milder form of dEDS. A skin biopsy sample was procured from a nearly 10-year-old Catahoula Leopard dog with dEDS associated with a previously published homozygous missense variant in ADAMTS2. Light and electron microscopic examinations were performed. Light microscopic examination of the skin sample revealed a substantially reduced density of collagen fibers that were randomly oriented and appeared to have a decreased length. Electron microscopic examination revealed diameters of the fibrils were variable, and scattered fibrils had irregular cross-sectional profiles, but lacked the "hieroglyphic" appearance identified in dogs with the frameshift variant in ADAMTS2. Like other species with dEDS, dogs can have variable disease severities that includes dermal collagen abnormalities.