Lordosis (L1, L2, L3, L4), also known as "Swayback", is a curvature or dip in the spine that is often seen in older horses. However, in the American Saddlebred, this condition also affects younger horses. These animals do not appear to experience pain from their condition and are still able to be used under saddle.

Malignant hyperthermia (MH) is a muscle disorder in which anesthesia, stress, or extreme exercise trigger a hyperthermic state. Symptoms include high temperature, increased heart rate, high blood pressure, sweating, acidosis, and muscle rigidity. If symptoms are not immediately resolved, death is likely to occur.

Myosin-Heavy Chain Myopathy (MY; previously "IMM") is a genetic muscle disease found most commonly in stock-type horses that can result in two different presentations, Immune-Mediated Myositis (IMM) and Nonexertional Rhabdomyolysis “tying up,” which are both characterized by muscle damage or loss. Both presentations are associated with the same genetic variant. Horses with MYHM may exhibit one or both presentations at different times in their lives, although some horses carrying the variant might not display any symptoms at all.

Myotonia (MYT) is a rare disorder involving a slowed relaxation of muscles after contraction. The most well-known example of myotonia is “fainting goats,” a breed that is characterized by sudden rigidy and/or falling over when startled. In the single documented horse, this resulted in a protruding third eyelid when excited, as well as problems with muscle stiffness.

Naked Foal Syndrome (NFS) is a recessive trait that results in the birth of foals with little to no hair and a general weakness. Death occurs early in life (weeks to months).

Occipitoatlantoaxial Malformation 1 (OAAM1) is an inherited developmental condition predominantly found in Arabian horses, characterized by abnormal development of the cervical vertebrae leading to compression of the upper cervical cord and subsequent neurological damage.

Polysaccharide Storage Myopathy (PSSM) is a glycogen storage disorder in which affected horses have chronic episodes of exertional rhabdomyolysis (“tying-up”). Acute symptoms are an unwillingness to move and muscle damage following exercise. Moderate symptoms can usually be managed through a low-sugar/starch diet and exercise.

Recurrent Laryngeal Neuropathy (RLN) is a disease that results in loss of the neurons that open the larynx, significantly affecting performance in Thoroughbreds and other sport horses. It is an important issue for horses in competitive events because the resultant paralysis of the larynx leads to obstruction of air flow during intense exercise, creating the abnormal inspiratory noise that gives RLN its common name: “roaring”.