You can't (your germ line mutations are fixed, and even if you could change your genes in place your brain has already developed according to the previous genetic code and environment). You can only choose where to direct the output of your already flipped switches.

People on Reddit are taking pills to try and do that. Sometimes you hear about them getting aggressive cancers. Other times you hear about them semi-successfully treating damage they did to their brains with past drug use. Randomized controlled trials never show anything, but if you're being held back from being a genius by one protein that you got a bad gene for, you'd be one of the positive testimonials without showing up above the noise in a trial. Who knows.

Ask again in 2122.

In the meantime, I guess, we all need to learn that our worth as a person is determined by who we are, not what we are.