Hyperkalemic Periodic Paralysis is a congenital autosomal dominant disorder. This means that the disorder starts at the time of birth. It also means that it only takes one parent with the disorder to pass it down to the offspring. The only way a horse will not be affected by the disease is if they are homozygous recessive for the gene.
Hyperkalemic Periodic Paralysis (HYPP) is caused by the mutation of the SCN4A gene. This gene is in charge of making special proteins that control the movement of skeletal muscle. SCN4A is used to create channels that allow sodium ions to flow into the different cells. (Genetics)
HYPP occurs when the channels become weakened which makes the muscles more susceptible to involuntary contraction. This leads to potassium