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Primary Open Angle Glaucoma (ADAMTS10 gene, Norwegian Elkhound)

Primary Open Angle Glaucoma (ADAMTS10 gene, Norwegian Elkhound)

Glaucoma is an inherited disorder characterized by an abnormal increase in intraocular pressure, which can lead to pain and even blindness.

Symptoms

Primary open-angle glaucoma develops slowly over weeks to months. Symptoms include loss of vision, pain, appearance of vessels in the eye, redness, corneal clouding, tearing, pupils of different size, vision problems, eye swelling, lack of appetite and depression. Glaucoma is a medical emergency and requires immediate attention to avoid irreversible damage to the retina and optic nerve.

Disease Management

Treatment of open-angle glaucoma focuses on restoring normal eye pressure and reducing pain. This type of glaucoma comes on slowly and, at least initially, can be kept under control with medications. Topical and oral medications may be used to lower eye pressure and treat inflammation or infection. In more severe cases, different surgical options such as cyclophotocoagulation, gonioimplantation or enucleation may be used.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

Primary open-angle glaucoma is characterized by increased intraocular pressure due to an imbalance between the production and drainage of intraocular fluid. Glaucoma is one of the leading causes of blindness worldwide. The ADAMTS10 gene belongs to the family of genes involved in the formation of elastic microfibril structures. Specifically, the protein encoded by ADAMTS10 is expressed in large amounts in the trabecular meshwork that is responsible for facilitating the drainage of aqueous humor, an essential fluid in the maintenance of proper ocular pressure. A mutation (c.1159G>A) in ADAMTS10 that results in the change of a highly conserved residue in the metalloprotease domain has been identified in the gray Norwegian Elk Hunter breed. This is a nonsense mutation in exon 9 that probably negatively affects the functional capacity of the protein.

Most affected breeds

Norwegian Elkhound

Bibliography

Ahonen SJ, Kaukonen M, Nussdorfer FD,et al. A novel missense mutation in ADAMTS10 in Norwegian Elkhound primary glaucoma. PLoS One. 2014 Nov 5;9(11):e111941.