Juvenile Hereditary Cataracts (JHC)

Quick Summary

Juvenile hereditary cataracts are an inherited form of cataracts that commonly cause blindness in dogs by clouding the lens of the eye and affecting both eyes symmetrically.

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Phenotype: Juvenile hereditary cataracts (JHC) affects both eyes symmetrically and has early onset, with cataract formation starting before 1 year of age and progressing to maturity and blindness by 2-3 years of age.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal, JHC = Juvenile hereditary cataract

Breeds appropriate for testing: Boston Terrier, French Bulldog, Staffordshire Bull Terrier

Explanation of Results:

  • Dogs with N/N genotype do not have the juvenile hereditary cataracts mutation and cannot transmit this variant to their offspring. However, cataracts may develop because of other genetic and environmental factors.
  • Dogs with N/JHC genotype may not develop juvenile hereditary cataracts, but are carriers. They will transmit this juvenile hereditary cataract variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% of puppies at risk for juvenile hereditary cataracts.
  • Dogs with JHC/JHC genotype may develop juvenile hereditary cataracts, a condition that progresses to blindness. 

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Turnaround Time
At least 15 business days; may be delayed beyond 15 business days if sample requires additional testing, or a new sample is requested.
Price

$55 single test per animal ($5 discount on 3 or more dogs)
$25 as additional health test on same animal

Sample Collection

Dog DNA tests are carried out using cells brushed from your dog's cheeks and gums. The preferred cytology brushes are sent to you by mail, or you may provide your own brushes. For accepted alternative brushes, click here

We recommend waiting until puppies are at least three weeks old before testing.

 

Dog having its cheeks and gums brushed for DNA samples
Cheek and gum brushing technique for canine DNA sample collection

Step-By-Step:

  1. Make sure the dog has not had anything to eat or drink for at least 1 hour prior to collecting sample.
  2. When swabbing puppies, isolate each puppy from the mother, littermates and any shared toys for 1 hour prior to swabbing. Puppies should not have nursed or eaten for 1 hour prior to collecting sample.
  3. If collecting samples from more than one dog, make sure to sample one dog at a time and wash your hands before swabbing another dog.
  4. Label brush sleeve with name or ID of dog to be sampled.
  5. Open brush sleeve by arrow and remove one brush by its handle.
  6. Place bristle head between the dog’s gums and cheek and press lightly on the outside of the cheek while rubbing or rotating the brush back and forth for 15 seconds.
  7. Wave the brush in the air for 20 seconds to air dry.
  8. Insert brush back into sleeve.
  9. Repeat steps 5 - 8 for each unused brush in sleeve on a fresh area of cheek and gums. Make sure to use and return all brushes sent by the VGL. In most cases, it will be 3 brushes per dog. If using interdental gum brushes, please note that the VGL requires 4 brushes per dog and only moderate or wide interdental gum brushes are accepted.
  10. Do not seal brushes in sleeve.
  11. Place all samples in an envelope and return to the address provided.

ATTENTION:

  • Do not collect saliva/drool – the key to obtaining a good sample is getting cheek cells on the swab
  • Do not rub swab on the dog’s tongue or teeth – this will result in poor quality sample
  • Do not collect a sample from a puppy that has recently nursed – the mother’s genetic material can rub off on the puppy’s mouth and contaminate the sample
Additional Details

Cataracts are a common cause of blindness in dogs. Cataracts are defined as the clouding (opacity) of the lens of the eye. The lens focuses light on the retina to enable vision. Cataracts can therefore impair vision and, if progressive, they can lead to total blindness. Cataracts can develop in one eye (unilateral) or both (bilateral) as a result of the normal aging process, underlying diseases, injury, or be caused by a genetic defect (primary hereditary cataracts). Primary hereditary cataracts tend to be of the bilateral type. In dogs, mutations in the HSF4 gene are associated with two different forms of cataracts, Juvenile Hereditary Cataracts (JHC) and Hereditary Cataracts (HC).

Juvenile Hereditary Cataracts (JHC) found in Boston Terriers, Staffordshire Bull Terriers, and French Bulldogs is a recessive disorder (2 copies of the mutation are necessary for cataracts to develop). JHC affects both eyes symmetrically and has early onset, with cataract formation starting before 1 year of age and progressing to maturity and blindness by 2-3 years of age. JHC affects both sexes equally. Mating of two carriers (N/JHC x N/JHC) is predicted to produce 25% of affected pups. JHC is distinct from the late-onset hereditary cataract also found in Boston Terriers and other breeds, the cause of which has not yet been identified.

Owners and breeders can benefit from this test by identifying at an early age which puppies will have the disease and which will not. Littermates that are either carriers (N/JHC) or clear of the mutation (N/N) are better candidates to retain for breeding purposes. Breeders should avoid mating 2 carriers that can produce affected dogs. Veterinarians can benefit from this test by determining if a clinical cataracts case in these breeds has a known genetic etiology.