Impaired Acrosomal Reaction Subfertility (IAR) causes sub- or infertility in males. In normal fertilization, the the head of a sperm binds to the egg and releases the contents of a structure known as the acrosome. However, some males with IAR are unable to properly carry out this process.

Junctional Epidermolysis Bullosa (JEB), also known as red foot disease or hairless foal syndrome, results in the inability to produce the proteins needed to keep the skin on the body. Affected foals exhibit symptoms within days of birth, including blisters at the pressure points, detatchment of the hooves, and oral ulcers. As there is no treatment, affected foals are humanely euthanized.

Kissing Spines Susceptibility (KSS) evaluates a horses genetic risk for developing Kissing Spines. Horses diagnosed with Kissing Spines will have two or more dorsal spinous processes that are too close together, touch, or even overlap. This bone-on-bone grinding causes varying degrees of pain, and thus decreased mobility.

Lavender foal syndrome (LFS), also known as coat color dilution lethal, is a neurological dysfunction in newborn foals. Symptoms are apparent at birth and include seizures, severe hyper-extension of limbs, neck and back, stiff paddling leg movements, involuntary eye movement and inability to stand or sit upright. The coat usually has a dilute color that ranges in shade from silver to a pale lavender/pink. As there is no treatment, affected foals are humanely euthanized.

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.

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).