It is currently thought that the causative mutation leads to collagen absence or deficiency in cartilage and ocular collagen, with a larger effect in vitreous and retinal tissue than in the limbs (Goldstein et al., 2010). Signs may be noticeable as early as 4 to 6 weeks of age. Affected dogs also have short-limbed dwarfism and vitreous dysplasia. In pups, the dome of the cranium is often pronounced and there is moderate excessive exotropic strabismus. Some, but not all, carriers have vitreal stands, focal retinal folds or plaques of retinal dysplasia. There is a range of ocular defects, but the most consistent findings are cortical equatorial cataracts and vitreal liquefaction. Histologic lesions in the growth plates included disorganization of cellular columns with abnormal extent of calcification, great variability in chrondrocyte shape, and premature cellular condensation in the maturation zone. Associated ophthalmic lesions include retinal detachment and cataracts.There is a test available to detect the causative mutation. Affected dogs are not reliably identified by clinical signs alone, so suspected dogs should be tested. Dogs having mild ocular lesions may be carriers and should be tested.