Primary Lens Luxation (PLL) is a well-recognised, painful and blinding inherited eye condition that affects many breeds of dog, particularly terrier and terrier-type breeds including (but not restricted to) Miniature bull terriers, Tibetan terriers, Jack and Parson Russell terriers, Lancashire Heelers and Chinese Crested dogs, also the Australian Cattle Dog, Jagd Terrier, Patterdale Terrier, Rat Terrier, Sealyham Terrier, Tenterfield Terrier, Toy Fox Terrier, Volpino Italiano, Welsh Terrier, Wire-haired Fox Terrier and Yorkshire Terrier.
In affected dogs the zonular fibres which support the lens breakdown or disintegrate, causing the lens to fall into the wrong position within the eye. If the lens falls into the anterior chamber of the eye glaucoma and loss of vision can quickly result.
Scientists at the AHT have identified a mutation that is associated with the development of PLL in several breeds of dog. The DNA test we are now offering examines the DNA from each dog being tested for the presence or absence of this precise mutation. It is thus a ‘mutation-based test’ and not a ‘linkage-based test’
Breeders will be sent results identifying their dog as belonging to one of three categories:
CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. Our research has demonstrated that carriers have a very low risk of developing PLL. The majority of carriers do not develop PLL during their lives but a small percentage do. We currently estimate that between 2% – 20% of carriers will develop the condition, although we believe the true percentage is nearer to 2% than 20%. We do not currently know why some carriers develop the condition whereas the majority do not, and we advise that all carriers have their eyes examined by a veterinary ophthalmologist every 6- 12 months, from the age of 2, throughout their entire lives.
GENETICALLY AFFECTED: these dogs have two copies of the mutation and will almost certainly develop PLL during their lifetime. We advise that all genetically affected dogs have their eyes examined by a veterinary ophthalmologist every 6 months, from the age of 18 months, so the clinical signs of PLL are detected as early as possible.
Frequently Asked Questions. If you have any questions about the PLL test please see if you can find an answer in our list of FAQ’s on our website PLL Genetics
Samples submitted should be cheek swabs ( a non-invasive sampling method). Sampling kits are obtainable from the Animal Health Trust webshop AHT DNA Testing. Further information can be obtained by emailing e-mail
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