Jack Russell Terrier: lens luxation (ADAMTS17) and genetic testing
An adult Jack Russell Terrier that suddenly starts squinting, keeps a red and painful eye, or hesitates before jumping may not simply have a knock or conjunctivitis: the breed is especially prone to a hereditary eye condition that can turn into an emergency fast. Find all our health guidance in the dog care and grooming section.
What the landmark study shows
Farias and colleagues published a genetic study in 2010 in Investigative Ophthalmology & Visual Science identifying a splice donor site mutation in the ADAMTS17 gene in dogs with primary lens luxation, with the Jack Russell Terrier among the breeds studied (study on Google Scholar). This protein plays a role in forming the zonular fibres that hold the lens in place behind the pupil; when they weaken, the lens shifts, sometimes forward into the eye, causing sudden pain and a risk of secondary glaucoma if left untreated. Inheritance is recessive, and a DNA test now distinguishes clear, carrier and at-risk dogs before any signs appear.
Why testing changes follow-up in practice
A dog flagged "at risk" by the genetic test won't necessarily develop the disease, but it warrants regular eye exams from around three or four years old, the age when the first lens shifts most often appear. Catching a luxation early, before it becomes complete, opens the door to preventive surgery rather than emergency care for an already painful eye.
- A DNA test before breeding, to know the dog's genetic status and set the right monitoring schedule.
- An annual eye exam from age three in carrier or at-risk dogs, even with no visible signs.
- An emergency visit at the first sign of a red, watery or abnormally dilated eye, since pain can set in within hours.
Repeated eye exams over several years add up to a budget worth planning for: our guide to pet insurance for dogs covers what different policies include. Find the full breed profile on the Jack Russell Terrier page and browse all our guides on the dog hub.
Frequently asked questions
Do all Jack Russells carrying the mutation develop luxation?
No, an at-risk genetic status raises the odds but does not guarantee the disease will appear; that's why eye exams stay essential even in a dog with no signs.
Does luxation affect one eye or both?
The second eye is very often affected after the first, sometimes within months, which is why close monitoring matters from the first episode onward.
Does early surgery prevent vision loss?
Removing a displaced lens before it triggers glaucoma preserves vision far better than surgery performed after complications have already set in.
This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.