The premise is pretty simple, what if we could press the undo button for DNA related aflictions. It's a sound theory but whether it would actually work or not is questionable.
This particular train of thought was mostly born from thinking about cancerous cells, which grow out of control due to a minute mutation in the DNA of a cell. The immune system doesn't identify the cancerous cells as something that is dangerous because they're near identical to any other healthy cell. The same could be said with aging, cells slowly mutating & loss of elasticity cause degradation in copying the genetic information to new cells.
CRISPR gene editing theoretically allows us to alter DNA in a live organism. With this technique the ability to alter a DNA sequence needs only the desired information payload to be spliced in. This obviously raises rather large ethical concerns of being able to wildly alter people's DNA and fundamentally change the human genome. Which is much too heavy a philosophical, cultural & even religious discussion for this particular blog! However, simply reverting to a previous non corrupted state of when the DNA was fresh & at its peak? There is no real change there, just a reversing back to a previous version.
In software development we have version control, most famously Git, which allows several versions of complex code & data to be merged together to get the intended end result. The same principle could surely be applied. People could regularly make DNA "commits", allowing the ability to merge, revert & even refresh changes to their own DNA sequence. Think of it like a save point, where the DNA could simply be pointed back to "load" a previous version. This would obviously need to be a regulated & controlled practice by medical professionals otherwise the below would most definitely occur. But if managed properly, the possibilities are quite enticing.