RE: Erste maßgeschneide Gentherapie erfolgreich am Menschen angewandt

You are right, he would (with a 100% chance) inherit this mutation to his offspring. But gene therapy that inflicts the germ line cells is even more dangerous. To manipulate our genome in that way is currently not yet feasible because you can´t be sure about some undesired other changes which could effect other genes in completely unexpected ways. And once it is better in control, I think it becomes even more dangerous because of the social implications (like the ones in the SF-film "Gattaca"). Or governments could enforce people to undergo gene therapy (or forbid them to have children). A dystopian world.