Is hypokalemia cureable even if it is genetic?

I know of no cure: Hyperkalemic periodic paralysis is what i think you are talking about. There are treatments for it including low carb diets and exercise limits and certain diuretics. But i don't know of a cure. I think some of the research with dna and viruses may eventually lead to sort of a cure. But this is still not for certain and many years in the future still.

Yes: Yes it can be treatable.

Cure hypokalemis: Yes it is possible. Some causes of inherited Hypokalemia that can be cured by kidney transplant include Liddle's syndrome and apparent mineralocorticoid from unrelated donor who does not have either of these genetic problems. But this is usually only done when kidneys have failed from the problem. But need more details.