Hereditary Cataracts (HC) Genetic Test | GenSol Diagnostics
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Hereditary Cataracts (HC)

$40.00

Cataracts are a clouding of lens of the eye caused by a breakdown of tissue in the eye. This generally results in an inability to see clearly, and can cause total blindness. In canines, mutations that result in cataracts can be passed to offspring and is known as Hereditary Cataracts (HC), Juvenile Cataracts (JC) or Early Onset cataracts (EOC). 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 with both eyes affected by the disease. The cataracts 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 HC 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 HC, 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 HC; however, the HSF4 gene mutation is not responsible for that particular form of cataracts. A separate mutation of the HSF4 gene is responsible for HC 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 do not develop cataracts, however, this interaction is not yet know. It is important to note that not all cataracts are hereditary. Cataracts can also be caused by old age or injury. Also, cataracts that occur in different regions of the lens can also be familial, but not necessarily attributed to this gene mutation.

Australian Shepherd
Boston Terrier
French Bulldog
Staffordshire Bull Terrier

Terrier and Bulldog:

A (CLEAR/NORMAL): These dogs have two copies of the normal gene and will neither develop HSF4-Hereditary Cataracts nor pass this mutation to their offspring.

B (CARRIER/NOT AFFECTED): These dogs have one copy of the normal gene and one copy of the mutation associated with this disease. They will not develop HC but will, if bred, pass the mutation to 50% of its offspring, on average.

C (AT RISK/AFFECTED): These dogs carries two copies of the mutant gene and are homozygous for HC. The dog is affected by HSF4-Hereditary Cataracts, and will always pass on a copy of the mutated gene to its offspring.

Australian Shepherd:

A (CLEAR/NORMAL): These dogs have two copies of the normal gene and will neither develop HSF4-Hereditary Cataracts nor pass this mutation to their offspring.

B (CARRIER/AT RISK): These dogs have one copy of the normal gene and one copy of the mutation associated with this disease. They will likely develop HC and will, if bred, pass the mutation to 50% of its offspring, on average.

C (AT RISK/AFFECTED): These dogs carries two copies of the mutant gene and are homozygous for HC. The dog will very likely be affected by HSF4-Hereditary Cataracts, and will always pass on a copy of the mutated gene to its offspring.

Hereditary Cataracts (HC)

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