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Primary Lens Luxation

Primary Lens Luxation (PLL) is an inherited eye disorder in dogs that causes the lens to dislocate, leading to pain and potential blindness.

Affected Genes: ADAMTS17

Inheritance: Autosomal Incomplete Dominant

Variant(canFam6):
chr3:43473765: G>A

Breed: American Eskimo Dog
American Hairless Terrier
Australian Cattle Dog
Australian Koolie
Australian Stumpy Tail Cattle Dog
Australian Working Kelpie
Biewer
Bull Terrier
Carlin Pinscher
Carolina Dog
Chinese Crested
Chinese Foo
Danish-Swedish Farmdog
Fox Terrier
German Hunting Terrier
Jack Russell Terrier
Jagdterrier
Koolie
Lakeland Terrier
Lancashire Heeler
Lucas Terrier
Miniature Australian Cattle Dog
Miniature Bull Terrier
Miniature Fox Terrier
Norfolk Terrier
Norwich Terrier
Parson Russell Terrier
Patterdale Terrier
Pomsky
Portuguese Podengo
Portuguese Podengo Pequeno
Puli
Pumi
Rat Terrier
Russell Terrier
Sealyham Terrier
Smooth Fox Terrier
Teddy Roosevelt Terrier
Tenterfield Terrier
Tibetan Terrier
Toy Fox Terrier
Volpino Italiano
Welsh Terrier
Wire Fox Terrier
Yorkiepoo
Yorkshire Terrier

General Information: Primary Lens Luxation (PLL) is a genetic eye condition affecting several dog breeds, where the lens dislocates due to the weakening or breakdown of the supporting ligaments, known as zonules. Typically presenting between 2 to 8 years of age, dogs with PLL may suddenly show signs of eye irritation such as excessive blinking, squinting, and tearing. The dislocation can occur in both forward (anterior) and backward (posterior) positions within the eye, with anterior dislocation being more serious and often leading to glaucoma and vision loss if not treated immediately. Symptoms of anterior lens luxation include red, teary, and cloudy eyes, as well as increased eye pain and bulging. Posterior dislocation causes milder inflammation and is less likely to result in glaucoma.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for PLL focuses on identifying mutations in the ADAMTS17 gene. PLL is inherited in an autosomal incomplete dominant manner, meaning that dogs with even one copy of the mutated gene are at increased risk of developing the condition. Dogs with two copies of the mutation are at the highest risk. Carrier dogs with one mutated gene may still develop PLL, although their risk is lower than that of dogs with two copies. Reliable genetic testing is crucial for responsible breeding practices. To avoid producing affected puppies, it is recommended not to breed two carriers. Each pup born to two carriers has a 25% chance of inheriting two copies of the mutation, leading to a high risk of PLL, and a 50% chance of inheriting one copy, also placing them at risk. Genetic testing before breeding helps in making informed decisions to eliminate this condition from breeding lines, ensuring healthier future generations.

References:
Donner J, Kaukonen M, Anderson H, Moller F, Kyostila K, Sankari S, Hytonen M, Giger U, Lohi H. Genetic Panel Screening of Nearly 100 Mutations Reveals New Insights into the Breed Distribution of Risk Variants for Canine Hereditary Disorders. PLoS One 2016 11(8):e0161005.

Farias FH, Johnson GS, Taylor JF, Giuliano E, Katz ML, Sanders DN, Schnabel RD, McKay SD, Khan S, Gharahkhani P, O'Leary CA, Pettitt L, Forman OP, Boursnell M, McLaughlin B, Ahonen S, Lohi H, Hernandez-Merino E, Gould DJ, Sargan DR, Mellersh C. An ADAMTS17 splice donor site mutation in dogs with primary lens luxation. Invest Ophthalmol Vis Sci. 2010 51(9):4716-4721.

Gharahkhani P, O’Leary C, DuffyD, Bernays M, Kyaw-Tanner M. Primary Lens Luxation in Australian Tenterfield and Miniature Bull Terriers is due to an old ADAMTS17 mutation and is an additive trait. Open Genomics J. 2012 5:7-13

Gould D, Pettitt L, McLaughlin B, Holmes N, Forman O, Thomas A, Ahonen S, Lohi H, O’Leary C, Sargan D, Mellersh C. ADAMTS17 mutation associated with primary lens luxation is widespread among breeds.Vet Ophthalmol. 2011 14(6):378-384.

Tzouganakis I, Tsvetanova A, Jeanes EC, Mellersh CS, Gould DJ. Investigation of the allele frequency of the G>A intron 10 ADAMTS17 mutation causing primary lens luxation in the Portuguese Podengo breed. Vet Ophthalmol. 2022 25(1):85-89.