Euphenics
Literally meaning 'normal appearing,' euphenics aims to improve the outcome of a genetic disease by altering the environment.
An illustration: children born with the genetic disease phenylketonuria (PKU) can avoid the expression of their disease by staying on a low-phenylalanine diet and avoiding major sources of phenylalanine such as diet soft drinks sweetened with aspartame (trade name: NutraSweet).