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POAG-PLL Shar Pei Type
| Acronym: | POAG, PLL |
| Gene: | ADAMTS17 |
| Mutation: | c.3069_3074del |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
POAG-PLL Shar Pei type is two different ocular neuropathies caused by the same mutation in the same gene. Primary open-angle glaucoma (POAG) is a hereditary eye disorder that causes a build-up of intraocular pressure, and primary lens luxation (PLL) is characterized by lens dislocation and loss of sight. Generally, glaucoma can be divided into two different forms of disorder, primary and secondary glaucoma. Primary glaucoma is characterized by its onset without any other ocular cause, while secondary glaucoma appears when another cause is present, which triggers glaucoma. Primary open-angle glaucoma belongs in the group of primary glaucoma together with primary angle closure glaucoma (PACG) and primary congenital glaucoma (PCG). In the Shar Pei breed POAG has not been well characterized, but it appears to be an open-angle rather than a closed-angle form. The disorder has been identified in several dog breeds, most of which are caused by breed-specific mutation, occurring only in that specific dog breed. Except for POAG Shar Pei type, other breeds with diagnosed POAG include the Beagle, Norwegian Elkhound, Basset Hound, Basset Fauve de Bretagne, and Petit Basset Griffon Vendeen.
PLL is caused by the displacement of the lens as a result of stretching or rupture of the zonular fibers that link ocular lenses in place behind the pupil. The disease can be caused by trauma or by a variety of conditions that distort normal ocular anatomies, such as glaucoma and intraocular tumors. Generally, encountered at high frequency in several terrier breeds and in some other breeds with probable terrier coancestry. POAG-PLL Shar Pei type is caused by a 6-bp deletion in the ADAMTS17 gene. The disorder is inherited as an autosomal recessive disorder. Healthy parents of an affected dog are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes are carriers and show no symptoms. At conception, each cub has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
James A. C. Oliver, Sophie Rustidge, Louise Pettitt, Christopher A. Jenkins, Fabiana H. G. Farias, Elisabeth A. Giuliano, Cathryn S. Mellersh (2018) A novel ADAMTS17 mutation is associated with primary open angle glaucoma and primary lens luxation in the Shar Pei. Am J Vet Res. 79(1):98-106. doi: 10.2460/ajvr.79.1.98.