Hyperkalemic periodic paralysis (HYPP) is an inherited disease that leads to uncontrolled muscle twitching or profound muscle weakness, and in severe cases, may lead to collapse and/or death.
• HYPP is listed as a genetic defect in AQHA's rules, along with Parrot Mouth and Cryptorchid conditions.
• To date, HYPP only has been traced to descendants of IMPRESSIVE, #0767246.
• Having negative (N/N) results on file may prevent a horse's offspring from being tested.
Possible results of HYPP testing are N/N, N/H and H/H.
HYPP is inherited as a dominant trait, which means a heterozygous (N/H) stallion or mare bred to a normal (N/N) horse will result in approximately half of the offspring being affected and half being normal. The rare homozygote (H/H) usually is severely affected with the disease and will pass the gene to its offspring 100 percent of the time.
This information can be found at http://www.aqha.com/association/registration/hypp.html