Primary Lens Luxation PLL Test Code 309
For breeds: American Eskimo Dog, American Hairless (Rat) Terrier, Australian Cattle Dog, Chinese Crested, Chinese Foo Dog, Jack Russell Terrier, Jagd Terrier, Lakeland Terrier, Lucas Terrier, Lancashire Heeler, Miniature Bull Terrier, Norwich Terrier, Parson Russell Terrier, Patterdale Terrier, Rat Terrier, Russell Terrier, Sealyham Terrier, Teddy Roosevelt Terrier, Tenterfield Terrier, Tibetan Terrier, Toy Fox Terrier, Volpino Italiano, Welsh Terrier, Wire-haired Fox Terrier and Yorkshire Terrier.
OptiGen is pleased to offer a mutation-based test for Primary Lens Luxation (PLL). This test is based on research conducted at the Animal Health Trust (AHT) in the UK by Gould et al. (Vet Ophthalmol. 2011 Nov;14(6):378-84). The PLL mutation has been identified in many breeds, primarily those of the terrier group, but also includes non-terrier breeds such as the American Eskimo Dog, the Chinese Crested and the Australian Cattle Dog.
PLL is an important inherited disease of the eye that is associated with disintegration of the zonule fibers that hold the lens in place. Once the lens is displaced from its normal position, i.e. it “subluxates” or “luxates”, serious and often painful secondary glaucoma can occur; blindness is a common outcome. PLL is always a bilateral condition, however there may be a period of several months or longer between the points when the two lenses luxate.
DNA test results for the PLL mutation will show that dogs are in one of three categories:
NORMAL/CLEAR: These dogs will not develop the condition due to the PLL mutation and will not pass the mutation on to their offspring.
CARRIER: These dogs carry ONE copy of the PLL mutation and ONE copy of the Normal gene. As stated by the AHT, where the original PLL work was conducted, “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%". Owners of PLL-Carrier dogs should discuss the test results with their veterinary ophthalmologist in order that a PLL monitoring plan can be put into effect.
AFFECTED: These dogs carry TWO copies of the PLL mutation and are very likely to develop PLL in their lifetime. Owners of PLL-affected dogs should discuss the test results with their veterinary ophthalmologist in order that a monitoring plan can be put into effect.
Because the incidence of PLL is very high in some breeds, breeders should be cautious in eliminating carriers from the breeding population too quickly and thereby removing desirable traits and/or introducing unknown recessive defects into the population. Any breeding pair should contain at least one dog that has been tested for PLL and is genetically NORMAL. Breeders should assess ALL of the prospective breeding dog’s traits, including its PLL genetic status as one factor in the assessment. By choosing breeding dogs based on the whole animal, not just a DNA test result, breeders can retain all of the good qualities of a dog/line while moving away from a disease mutation identified by a specific DNA test.