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 12 months and 3 years of age in Staffordshire Bull Terriers. DNA testing is readily available for this disease.

*It should also be noted 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, however, are not attributed to this gene mutation. This is why a eye screen by a board certified ophthalmologist is recommended to get clearance from other hereditary or congenital eye anomalies that may be present