You cannot patent gene repair with CRISPR-CAS because that's long been patented (and also disputed by multiple entities).
If several genes are faulty and I repair them what would be the innovation? The detection of a specific set of faulty genes? The order of repair?
Big Pharma has long figured this out and I have inside knowledge from people who know that this is the reason they're not pursuing it.
P.S.: Big Pharma is now quietly also researching gene repair but I believe it's to hedge their bets. Maybe they're counting on "lobbying"/bribing politicians to allow them to patent gene repair regardless.
You can't patent "repairing a road" but you can absolutely patent a new mechanism to do so.
Most patents are of this form - there are far more patents for improved ways of doing things than initial ways of doing things.