Paint registry to require genetic testing

The American Paint Horse Association will require testing for six heritable diseases.


For the first time, the American Paint Horse Association (APHA) will require testing for genetic diseases.

In February, the APHA Board of Directors approved a new rule mandating that all breeding stallions be tested for six genetic conditions in order for their offspring to be eligible for registration.

Referred to collectively by the APHA as the Genetic Health Panel, the required tests are for the following conditions:

• hyperkalemic periodic paralysis (HYPP)

• polysaccharide storage myopathy (PSSM)

• malignant hyperthermia (MH)

• glycogen branching enzyme deficiency (GBED)

• hereditary equine regional dermal asthenia (HERDA)

• overo lethal white syndrome (OLWS)

Testing will be done through APHA-approved laboratories, and the results of each breeding stallion’s panel will be available to all members, allowing owners to avoid breedings that might result in offspring with these diseases. The results of each stallion’s Genetic Health Panel must be on file with the APHA prior to registration of offspring resulting from breedings occurring after January 1, 2018.

The rule, which was passed at the APHA convention in Richmond, Virginia, was originally proposed by Robin Davison, a Colorado horsewoman who owns a mare with the genetic disease HERDA. (For more information, see “In the Skin,” Case Report, EQUUS 411.) “Testing stallions is where the rubber meets the road, since a single stallion can produce many foals,” says Davison, “It’s critical for mare owners to have this information so they can make informed breeding decisions.”

After officially requesting the rule change, Davison traveled to the APHA convention and lobbied for its passage. “I was surprised at how many people thought HERDA was ‘just that skin disease,’” she says. “They had no idea it was a systemic collagen disorder that affects the entire body, from ulcerated corneas0 to paper thin heart valves and hyper-extendable tendons and ligaments. I spent much of my time just educating people on HERDA.”

Davison says her mare, Penelope, is now 9 years old and, in addition to chronic skin lesions, has advanced arthritis because her overly flexible ligaments do not sufficiently support her skeletal structure.

“One of the most exciting things about APHA governance is that anyone who wants to campaign for a rule change and who has the enthusiasm and willingness to do so can get a rule passed,” says Billy Smith, the organization’s executive director.

And although her personal experience has been with HERDA, Davison says it was important to her that the rule include all detectable genetic diseases. “I was always thinking of the bigger picture,” she says. “It was about doing something for the good of the entire breed.”

This article first appeared in EQUUS issue #464, May 2016.