Hereditary Cataracts
Affected Genes: HSF4
Inheritance: Autosomal Recessive
Variant(canFam6):
chr5:82186736: 1 bp insertion G
Breed: Aussiedoodle
Australian Labradoodle
Bernedoodle
Bordoodle
Boston Terrier
Cavapoo
Cavapoochon
Cockapoo
Danoodle
French Bulldog
Goldendoodle
Irishdoodle
Labradoodle
Maltipoo
Miniature Poodle
Newfypoo
Poodle
Schnoodle
Sheepadoodle
Shorty Bull*
Staffordshire Bull Terrier
Standard Poodle
Toy Poodle
Wire Fox Terrier
Yorkiepoo
General Information: Hereditary Cataracts (HC) in dogs results from a genetic mutation that causes the lens of the eye to become opaque, obstructing vision. The disease typically presents early, often within weeks to months of birth, initially as small, discrete opacities detectable during a veterinary eye exam. These cataracts progressively enlarge and usually culminate in total blindness by two to three years of age. While hereditary factors primarily drive the development of this condition, environmental influences such as exposure to ultraviolet light can exacerbate its severity. This progression can lead to complete vision loss, significantly impacting a dog's quality of life.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog Unlikely Affected
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing for Hereditary Cataracts (HC) centers on the HSF4 gene, which, when mutated, is known to cause this eye condition. HC follows an autosomal recessive inheritance pattern; thus, a dog needs to inherit two copies of the mutated gene, one from each parent, to exhibit symptoms of the disease. Dogs with one copy of the mutated gene (carriers) do not typically show symptoms but can pass the mutation to their offspring. Breeding two carriers results in a 25% chance of producing affected offspring and a 50% chance of producing another carrier. Effective genetic testing is crucial to identify carriers and affected dogs to prevent the propagation of this condition in future generations. Breeders are advised to avoid mating carriers to prevent the birth of affected puppies. Dogs tested free of this mutation do not carry the genetic risk for developing or transmitting hereditary cataracts.
References:
Barnett KC. Hereditary cataract in the dog. J Small Anim Pract. 1978 19(2):109-20.
Mellersh CS, Graves KT, McLaughlin B, Ennis RB, Pettitt L, Vaudin M, Barnett KC. Mutation in HSF4 associated with early but not late-onset hereditary cataract in the Boston Terrier. J Hered. 2007 98(5):531-533.
Mellersh CS, Pettitt L, Forman OP, Vaudin M, Barnett KC. Identification of mutations in HSF4 in dogs of three different breeds with hereditary cataracts. Vet Ophthalmol. 2006 9(5):369-378.