GLUCOMA and GONIODISGENESYS

Due to abnormal development of intraocular fluid egress channels inside the eye the iridocorneal angle, through which the excessive chamber fluid is filtered and drained, get narrower or closed. The primary glaucoma or glaukoma is a painful eye disease that is often associated with elevated intraocular pressure. This increased pressure within the eye damages the ganglion layer of retina and leads to blindness.

This disease was first observed in Border Collies in Australia in the late 1990s and has subsequently been found in Europe and the USA, mainly in dogs related to the affected Australian dogs. Recently, many dogs in the USA become affected with severe goniodysgenesis and glaucoma. Besides Border Collies, the disease also affects other breeds such as Flat Coated Retriever, Springer Spaniel, Cocker Spaniel, and Basset hound, Golden Retriever or Leonberger.

Severe goniodysgenesis potentially leading to glaucoma is connected with homozygosis for A-allele of OLFML3-gene which indicates autosomal recessive mode of inheritance. The vast majority of dogs with severe goniodysgenesis and glaucoma are homozygous for the mutation mentioned, however there are some cases of heterozygotes affected with this disease. The exact mode of inheritance has not been elucidated yet.

In some dogs, the glaucoma has not been diagnosed although suffering from severe goniodysgenesis. This finding indicates that it is essential for glaucoma occurrence; however for the progress of severe goniodysgenesis to glaucoma a combination of other genetic, environmental or random factors supporting its development is needed.

Predisposition to this disease can be genetically tested through blood or cheek swab samples and clinically tested through ophtalmological tests.

There is an available database on the following link:

Glaucoma/Gonio database

Autosomal recessive heredity

Parent 1 genotype

Parent 2 genotype

Normal

Carrier

Affected

Normal

All Normal

½ Normal
½ Carrier

All Carriers

Carrier

½ Normal
½ Carriers

¼ Normal
½ Carriers
¼ Affected

½ Carriers
½ Affected

Affected

All Carriers

½ Carriers
½ Affected

All Affected