You have spent years to identify the gene for a rare, dominantly inherited paralytic disease.The disease is characterized by a temporary inability to generate action potentials in the muscle after heavy exercise.
The gene you finally identify encodes an inwardly rectifying potassium channel, and the disease is correlated with a single amino acid change in its selectivity filter.
Experiments on mutant channels expressed in cultured cells indicate that the channel becomes less selective for K+ when lactic acid builds up and the residue is protonated.
What is the single most likely etiology for the disease?
