AQHA does have guidelines for HYPP and registration but this little guy is a solid APHA (Paint).
Also if you go back in his pedigree to Impressor (four generations back) even though he is a son of Impressive his HYPP status is:
IMPRESSOR H, QUARTER HORSE, 1974
Color: br
#1000542
HYPP N/N
H-34
1975 Open World Champion Yearling Halter Stallion
AQHA registration regarding HYPP:
© Hyperkalemic Periodic Paralysis (HYPP)-designation effective for foals born on or after January 1, 1998. A muscular
disease caused by a hereditary genetic defect that leads to uncontrolled muscle twitching or profound muscle weakness,
and in severe cases, may lead to collapse and/or death. According to research, this condition exists in certain
descendants of the stallion Impressive, AQHA registration number 0767246.
(1) The following notification shall be placed on registration certificates of foals descending from the stallion Impressive or
any other bloodline determined to carry the HYPP gene:
This horse has an ancestor known to carry HYPP, designated under AQHA rules as a genetic defect. AQHA
recommends testing to confirm presence or absence of this gene.
When the parent(s) tracing from the HYPP line has tested negative for HYPP with an appropriate designation appearing
on their registration certificate, the above notification is not required, and will, instead, be substituted by the designation
N/N; or, after testing negative for the gene, the notification may be substituted by the designation N/N upon request of
the owner at his or her expense.
(2) Mandatory testing for HYPP. At such time as AQHA requires mandatory parentage verification of any foals to be
registered in either the numbered or appendix registry, (see 202(g) any foal tracing to bloodlines known to carry the HYPP
gene, shall be tested for HYPP at the time the genetic testing for parentage is performed. The results will be designated
on the registration certificate in lieu of the above notification. Such testing will not be necessary if the foals closest
ancestors, tracing to the HYPP line, have been tested negative, and designated on their registration certificates, which
foals will automatically be designated N/N on their registration certificate.
(3) Effective with foals born on or after January 1, 2007, all descendants of the of the stallion Impressive, AQHA
registration number 0767246, shall be required to be parentage verified and HYPP tested, subject to the
conditions in ©(2) above. Any foal testing homozygous positive for HYPP (H/H) will not be eligible for
registration with AQHA.