Hyperkalemic Periodic Paralysis (HYPP)

HYPP is associated with the Impressive bloodline.  Magic is a son of Impressive.  He is HYPP N/N meaning he cannot pass on the gene for HYPP.  The AQHA is considering the following changes regarding HYPP:

            Rule 227 will be amended, making foals of calendar year 2006
             and after ineligible for registration if they are descendants of    
            the stallion Impressive and HYPP positive (H/H).

            Additionally, Rule 227 will be amended to provide that foals   
             of 2010 and later that are HYPP carriers (N/H) will only be
             eligible for registration as geldings or non-breeding mares.

The following is a verbatim fact sheet produced by the AQHA:

*Hyperkalemic periodic paralysis (HYPP) is an inherited disease that leads to uncontrolled muscle twitching or profound muscle weakness.  In severe cases HYPP may lead to collapse and/or death.

*HYPP is listed as a genetic defect in AQHA'a rules.

*To date, HYPP has been traced only to descendants of IMPRESSIVE  #0767246.

*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.  A horse that has tested N/N does not have the gene that causes this condition and will not pass it to any offspring.  Possible results of HYPP testing are N/N, N/H and H/H.

*Having negative (N/N) results on file may prevent a horse's offspring from being tested.

(Magic's offspring do not need to be tested unless the mare traces back to IMPRESSIVE and does not have (N/N) on file)

*Unless test results are on file with AQHA indicating a foal is negative (N/N), foals born in or after 1998 and tracing to IMPRESSIVE will have a statement placed on their certificates of registration the recommends testing for the condition.

*Beginning in 1998, all foals that must be parentage verified and who trace to IMPRESSIVE will be tested for HYPP with the same DNA sample submitted to the laboratory for parentage verification.  This would include those resulting from the use of transported semen or embryo transfer.

*AQHA will accept HYPP test results only if performed through a licensed laboratory and a properly signed identity waiver is provided. These currently include: University of California at Davis; Shelterwood Labs in Carthage, Texas; Mann Equitest Labs in Guelph, Ontario; NSW Agriculture in Wales, Australia, Vita-Tech Canada Inc. in Markham, Ontario; and Stormont Labs in Woodland, California.

*AQHA testing kits can be ordered for $35.

*HYPP can be treated through diet and medication in most cases.  For more information concerning this disease, call AQHA at (806) 376-4811and request the HYPP brochure.