Juvenile Hereditary Cataracts (JHC) cause a clouding of the lens of the eye due to a breakdown of tissue in the eye. This condition generally results in an inability to see clearly and can cause total blindness. In canines, cataracts are often familial; this is known as Hereditary Cataracts. A mutation in the HSF4 gene causes this type of cataracts in several breeds of dogs. In this case, the dog is typically affected bilaterally. This means that both eyes are affected by the cataracts. The cataracts associated with HSF4 also occur in the posterior region of the lens. They usually start by being small and grow progressively, though the speed of growth is highly variable. Some cataracts will grow so slowly that the dog's vision remains relatively clear, while others will grow such a way that the dog will quickly go blind. Corrective surgery is possible, though it is costly and is not always effective.
One HSF4 mutation causes the recessive form of Juvenile Hereditary Cataracts (JHC) in Boston Terriers, Staffordshire Bull Terriers, and French Bulldogs. Because it is recessive, a dog must have two copies of this mutation to experience this form of cataracts. This mutation is only responsible for early-onset hereditary cataracts, which typically occur between 2-3 years in Boston Terriers. Boston Terriers can also be afflicted by late-onset hereditary cataracts. However, the HSF4 gene mutation is not responsible for that particular form of cataracts. The causative gene for late-onset hereditary cataracts in Boston Terriers has not been determined at this time.
Degenerative Myelopathy or DM is a disorder that affects the spinal cord of Boston Terriers and other dog breeds that may lead to paralysis. DM is a progressive degeneration of the dog's hind legs due to a portion in the spinal cord that is not functioning properly. After progressive degeneration comes total paralysis.
Brainstem Auditory Evoked Response (BAER), also known as Brainstem Evoked Potential (BSEP), testing is a hearing assessment that can be used to evaluate the hearing in dogs, cats and other domestic animals. Not only does the test measure hearing, but it can also be used to test brainstem functionality.