Most diseases are affected to some extent by both genes and the environment. A genetic disorder is one in which an abnormality in the genetic make-up (the genome) of the individual dog plays a significant role in causing the condition.

For many of the disorders that are believed to be inherited, some are more common in specific dog breeds. This is known as a breed’s predisposition.

Some problems are considered hereditary because they tend to appear only in certain breeds or certain varieties of one same breed. The predisposition to inherit skin allergies, some types of tumors and certain types of epilepsy seem to be transmitted from parents to children in some blood lines, but they also appear in others.

Hip dysplasia is the most common of the hereditary diseases. Although it affects larger breeds more frequently than smaller breeds, it can affect individuals of any breed. It is an abnormal formation of the hip socket which prevents the ball joint from fitting comfortably into the socket and prevents smooth movement. Symptoms of hip displasia include an unwillingness to run and play, trouble getting up and down the stairs or popping or snapping sounds when walking.

Glaucoma, a group of eye diseases which are characterised by an increase in intraocular pressure that can lead to varying degrees of blindness, is another of the genetic disorders that affect dogs. This disease is not limited to small or large breeds, although the Collie breeds are one of the breeds more prone to contracting the disease. Primary Glaucoma is an increase in intraocular pressure occurring in an eye without previous diseases or injury being the cause while secondary Glaucoma usually occurs where an injury or prior disease leads to the condition. The symptoms include a milky appearance to the eye and often eye discharges.

Persistent Hyperplastic Primary Vitroeus (PHPV). HC is inherited through a recessive gene causing the embryonic blood vessels within the eye to develop and persist abnormally after birth. The blood vessels are in the back of the eye from the optic nerve to the back of the lens and frequently cause cataract. A plaque of fibrous tissue, sometimes with pigment, is seen on the back of the lens. The disease can be graded (1-6) based on severity.

In mildly affected cases, dogs may be unlikely to have further problems and can live a normal life while dogs more severely affected can have a high risk of problems such as the development of secondary cataracts which may result in blindness.
The symptoms are similar to Glaucoma, producing a strange appearance on one or both of the eyes.

Although it is not necessary for pet owners to have a scientific understanding of genetic disorders, it may be useful and convenient to have a basic knowledge of these diseases to be able to recognise the problems and their symptoms to maintain a long and healthy life for your dog.