Hyperkalaemic periodic paralysis (HYPP)
HYPP is one of the 5 tests in the 5-panel. The 5-panel is relevant to Quarter Horses, Paints, Appaloosas, Quarter Ponies and any other breeds with some Quarter Horse bloodlines. HYPP is only found in the descendants of Impressive, an American Quarter Horse born in 1969. Impressive was a halter horse World Champion that produced a large number of World Champion offspring.
The most common signs of HYPP are muscle twitching and spasm occurring intermittently and starting at 2-3 years of age. Severe cases can have muscle weakness, with the worst instances causing collapse or death. HYPP carriers are also reported to have a marked increase in musculature.
The HYPP test is only relevant to horses with Impressive in their pedigree. Just remember if you’re checking your horse’s pedigree to go back far enough to reach 1969 or earlier. HYPP is extremely rare here in Australia.
Gene or region and technical reference
Gene: SCN4A (causative). Reference: Rudolph et al. (1992)
n. Test developed using manufactured DNA, animal controls.
HYPP. Test developed using manufactured DNA.