Animal Genetics Inc. and The Animal Health Trust have agreed to a long-term contract to run JHC testing in the United States
Hereditary Cataracts Panel for Boston Terriers, Staffordshire Bull Terriers, and French Bulldogs, as well as Australian Shepherds. Current price is $45.00 per dog. Discounts for clubs and club sponsored events are available.
Cataracts are a clouding of the lens of the eye caused by a breakdown of ocular tissue. This generally results in an inability to see clearly and can cause total blindness. In canines, cataracts are often familial; this type 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, in that both eyes are affected by the cataracts. The cataracts
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| Cataracts are a clouding of the lens caused by a breakdown of tissue in the eye. |
associated with HSF4 also occur in the posterior region of the lens. They usually begin 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 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 Hereditary Cataracts 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 12 months and 3 years of age in Staffordshires, and 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.
A separate mutation of the HSF4 gene is responsible for Hereditary Cataracts in Australian Shepherds. This mutation affects Aussies differently, in that the disease is dominant, but not completely penetrant. This means that only one copy of the mutation is necessary to predispose a dog to the disease. However, incomplete penetrance means that a dog that has this mutation will not always develop HC. Research suggests that the mutation makes a dog 12 times more likely to develop posterior bilateral cataracts at some point in their lifetime. It is likely that a secondary gene interaction occurs in the small percentage of dogs possessing the HC mutation but that do not develop cataracts, however, this interaction is not yet known.
