Primary Lens Luxation (PLL)
Primary Lens Luxation (PLL) is a well-recognised, painful and blinding inherited
eye condition that affects many breeds of dogs.
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 have identified a mutation that is associated with the development of PLL in several breeds of dog. DNA test we are now available to breeders and results will be sent identifying their dog as belonging to one of three categories:
CLEAR: these dogs have two normal copies of DNA. Research has demonstrated clear dogs will not develop PLL as a result of the mutation tested for, although it cannot exclude the possibility they might develop PLL due to other causes, such as trauma or the effects of other, unidentified mutations.
CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. The majority of carriers do not develop PLL during their lives but a small percentage do.
GENETICALLY AFFECTED: these dogs have two copies of the mutation and will almost certainly develop PLL during their lifetime. Advice states 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. Affected dogs often go blind at about 5-6 years old.
Responsible breeders will test for PLL and make appropriate breeding choices to minimise or eliminate the occurrence of this disorder.
Carriers of PLL can continue to be used in breeding programs as long as they are only mated with PLL clear animals. This practise should be followed, to allow the PLL mutation to be slowly eliminated from the population.
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