There is a lot of research on this, but "patching up the genome" isn't possible that way. Gene therapy generally only inserts DNA into a cell (by whatever mean

There is a lot of research on this, but "patching up the genome" isn't possible that way. Gene therapy generally only inserts DNA into a cell (by whatever means possible). Inside the cell, it gets used almost as if it where inside the actual genome. The problem is reaching enough cells and getting the genes to work well enough...