Primary Lens Luxation (PLL)
Primary Lens Luxation is a disorder that is characterized by weakened zonular fibers which eventually lead to the dislocation of the lens in the eye. In the eye of a canine, the lens is located directly behind the iris and the pupil. It is responsible for focusing light to the retina in the back of the eye. The zonlular fibers are responsible for holding the lens in place. In dogs affected by PLL, these fibers are much weaker and can allow the lens to dislocate or luxate. This is very painful for the dog and depending on where the lens moves to, can leave the dog permanently blind. Often, this event will occur around 3-6 year of age. it is recommended that all dogs genetically affected by PLL be evaluated by a veterinarian every 6 months to monitor the condition of the eyes.
Progressive Retinal Atrophy, Progressive Rod-Cone Degeneration (PRA-prcd)
Progressive retinal atrophy, progressive rod-cone degeneration is the late onset, inherited eye disease affecting many breeds of dog. PRA-prcd occurs as a result of degeneration of both rod and cone type photoreceptor cells of the retina, which are important for vision in dim and bright light, respectively. Evidence of retinal disease in affected dogs can first be seen on an electroretinogram around 1.5 years of age for most breeds, but most affected dogs will not show sighs of vision loss until 3-5 years of age or later. The rod type cells are affected first and affected dogs will initally have vision deficits in dim light (night blindness) and loss of peripheral vision. Over time affected dogs continue to lose night vision and begin to show visual deficits in bright light. Other signs of progressive retinal atrophy involve changes in reflectivity and appearance of a structure behind the retina call the tapetum that can be observed on a veterinary eye xam. Although there is individual and breed variation in the age of onset and the rate of disease progression, the disease eventually progresses to complete blindness in most dogs. Other inherited disorders of the eye can appear similar to PRA-prcd. Genetic testing may help clarify if a dog is affected with PRA-prcd or another inherited condition of the eye.
Rod Cone Dysplasia 4 (RCD-4)
Rod-cone dysplasia 4 is an adult-onset progressive eye disorder characterized by degeneration of retinal photoreceptor cells leading to loss of vision and eventually to blindness. The first observable clinical sign is vision loss in dim light (night blindness) caused by degeneration of rod cells. The disorder gradually progresses to total blindness as the cone cell of the retina also degenerate. The first clinical signs are usually noted at around 10 years of age, but the age of onset can vary between 5 and 12 years.
Degenerative Myelopathy (DM)
Degenerative Myelopathy is a debilitating disease that causes gradual paralysis in many dog breeds. It is caused by a degeneration of the spinal cord that onsets typically between 8 and 14 years of age. It presents first with the loss of coordination in the hind legs. It will typically worsen over 6 months to a year, resulting in paralysis of the hind legs. If signs progress for a longer period of time, loss of urinary and fecal continence may occur and eventually weakness will develop in the front limbs. An important feature of Degenerative Myelopathy is that it is not a painful disease.
Myotonia Congenita (MC) (ACD type)
Myotonia Congenita is an inherited muscle disorder affecting dogs. The muscle cells of an affected dog are over-excitable, which causes muscles to remain contracted rather than relaxing after voluntary activity. Affected dogs frequently have a "bunny hop" type gait. Episodes do not appear to be painful and the muscle stiffness may improve with increased exercise. Episodes can worsen with cold and excitement. Other features include enlargement of the muscles, abnormal posture, an upper jaw that is much longer than the lower jaw, and dental abnormalities. Dogs may also exhibit excessive panting and salivation, have an abnormal bark and loud raspy breathing, and have difficulty swallowing. Dogs with this disorder typically have a normal lifespan.
Cystinuria (CSNU) (ACD type)
Cystinuria (ACD type) is an inherited disease affecting kidney function in dogs. Normal kidneys reabsorb the Amino Acid Cystine so that only small amounts pass into the urine. Cystine can cause crystals and /or stones in the urinary tract which can block the ureters and stop the normal flow of urine. Symptoms of the disease include straining to urinate, frequent urination of small volumes or the inability to urinate. Dogs with Cystinuria often have recurrent inflammation of the urinary tract and if not treated, urinary stones can cause urinary tract infections, kidney failure and even death.