Named for its high prevalence in Collie dogs, Collie Eye Anomaly (CEA) is more correctly termed choroidal hypoplasia. The choroid anchors the retina to the underlying structures and supplies it with oxygen and nourishment. CEA is a developmental disease of the choroid.

This condition causes kidney and bladder stones composed of urate. In most dogs, uric acid is converted to allantoin, an inert substance that is then excreted in the urine. Dogs with HUU have defects in the pathway that converts uric acid to allantoin. As such, uric acid builds up, crystallizes and forms urate stones in the kidney and bladder. Uric acid is an intermediate of purine metabolism. While hyperuricemia in other species (including humans) can lead to painful conditions such as gout, dogs do not develop systemic signs of hyperuricemia.

Sensitivity to certain classes of drugs, notably the parasiticide ivermectin, as well as certain gastroprotectant and anti-cancer medications, occurs in dogs with a mutation in the ABCB1 gene.

PRA-prcd is a retinal disease that causes progressive, non-painful vision loss. The retina contains cells, called photoreceptors, that collect information about light and send signals to the brain. There are two types of photoreceptors: rods, for night vision and movement, and cones, for day vision and color. This type of PRA leads to early loss of rod cells, leading to night blindness before day blindness.

Neutrophils, a type of white blood cell that fights infections, are generated in the bone marrow. After an appropriate time to mature, they leave the bone marrow and enter the circulation. The neutrophils of dogs with TNS never fully mature, but remained trapped" in various stages of immaturity in the bone marrow."