From BBC:
Given that many women may be carrying the mutation, why do so few people prove to have such astonishing vision, for instance? “One possibility is that you need early training to capitalize on the signal,” says Kimberly Jameson at the University of California, Irvine, who has tested Antico extensively.

For the full story, please visit http://www.bbc.com/future/story/20160316-i-can-see-colours-you-cannot-perceive-or-imagine.