Test Detail

Progressive weakening of the zonules of Zinn that causes displacement of the lens. It is a hereditary, non-inflammatory ocular disease, distinct from luxations secondary to cataract, uveitis, previous glaucoma or trauma. When the lens moves into the anterior chamber it can trigger a painful acute glaucoma and rapid blindness: it is an ophthalmological emergency. The molecular test detects the classic ADAMTS17 variant associated with PLL.

Breeds with the classic c.1473+1G>A variant documented in OMIA:000588-9615: American toy terrier, Chinese crested, German hunting terrier, Jack Russell terrier, Lancashire heeler, Bull terrier miniatura, Parson Russell terrier, Patterdale terrier, Rat terrier, Sealyham terrier, Tenterfield terrier, Tibetan terrier, Toy fox terrier, Volpino italiano, Welsh terrier, Wire fox terrier and Yorkshire terrier. Gould et al. (2011), when screening 30 breeds, identified this variant in 14 additional breeds (many of them terriers or of terrier ancestry). The Chinese Shar-Pei and the Brittany spaniel do NOT carry the classic variant: the Shar-Pei has an independent in-frame deletion (OMIA variant 942) and the Brittany spaniel a genetically distinct form. No verifiable population frequency estimates are available: limited data.

- Recessive inheritance: avoid carrier x carrier mating (25 % risk of affected homozygotes).\n- An affected animal must not be bred; a carrier can be mated to a clear animal without producing affected offspring.\n- Periodic ophthalmological examination under mydriasis in every breeding line, even if the genetic test is favourable.\n- Record clinical cases of luxation to monitor variants not covered by the test.

Differentiate from secondary luxation (hypermature cataract, uveitis, previous glaucoma, trauma), essential for interpreting the test in animals without a pedigree. Urgent treatment of the anterior lens: transient topical miotics and surgery (lensectomy/phacoemulsification). Monitor both eyes: the second lens usually luxates within months or years. Gonioscopy is recommended in breeds predisposed to associated glaucoma. The DNA test does not replace annual ophthalmological screening, since other ADAMTS17 variants exist.

1. Farias FH, Johnson GS, Taylor JF, et al. An ADAMTS17 splice donor site mutation in dogs with primary lens luxation. Invest Ophthalmol Vis Sci. 2010;51(9):4716-4721. PMID: 20375329.
2. Gould D, Pettitt L, McLaughlin B, et al. ADAMTS17 mutation associated with primary lens luxation is widespread among breeds. Vet Ophthalmol. 2011;14(6):378-384. PMID: 22050825.
3. Oliver JAC, Rustidge S, Pettitt L, et al. Evaluation of ADAMTS17 in Chinese Shar-Pei with primary open-angle glaucoma, primary lens luxation, or both. Am J Vet Res. 2018;79(1):98-106. PMID: 29287154.
4. Lewis TW, Mellersh CS. Changes in mutation frequency of eight Mendelian inherited disorders in eight pedigree dog populations following introduction of a commercial DNA test. PLoS One. 2019;14(1):e0209864. PMID: 30650096.
5. OMIA:000588-9615. Lens luxation in Canis lupus familiaris. https://omia.org/OMIA000588/9615/