Robert Muttenhammer

Collie Eye Anomaly is an inherited developmental defect affecting the eye, specifically the retina (the light-sensitive tissue at the back of the eye) and the choroid (the underlying layer of blood vessels). This genetic condition causes these structures to develop abnormally before birth. It is primarily seen in herding breeds and is inherited in an autosomal recessive manner.

The merle coat pattern is caused by an autosomal-dominant mutation in the PMEL gene, which affects pigment-producing cells in the skin, eyes, and inner ears. When a dog inherits two copies of this gene, a condition known as double merle, it disrupts the normal development of these sensory organs. This genetic defect can lead to severe structural abnormalities in both the auditory and visual systems.

A cataract is a progressive clouding of the lens inside the dog's eye, which is the clear structure that focuses light onto the retina at the back of the eye. When the lens becomes cloudy or opaque, it blocks light from entering, gradually impairing the dog's vision. If left untreated, this condition can eventually lead to complete blindness in the affected eye.

Epilepsy is a chronic disorder of the brain and nervous system where abnormal electrical activity causes sudden, temporary disruptions in normal brain function. These disruptions lead to repeated seizures, which are involuntary changes in body movement, sensation, or behavior. Because the underlying cause is often complex, the brain's electrical signaling remains permanently prone to these sudden misfires.

Heart disease refers to structural or functional abnormalities of the heart muscle, valves, or electrical system that impair its ability to pump blood effectively. This reduced pumping efficiency prevents the cardiovascular system from delivering adequate oxygen and nutrients to the body's tissues. Some forms are congenital, meaning present from birth, while others are acquired over time due to wear or genetic factors.

Retinal dysplasia is a congenital condition affecting the eyes, where the retina (the light-sensitive tissue at the back of the eye) does not develop properly during growth in the womb. This abnormal development leads to structural defects like folds or gaps in the retinal layers. Because the retina is responsible for sending visual signals to the brain, these imperfections can impair normal vision.