Corruption works the same as for regular support gems, sometimes adding or removing a level or up to 10 quality. Quality is hardcapped at 23%.
No effect (other than adding the corrupted property).
Add or subtract one level. Max level gems can exceed their normal maximum this way. A corrupted awakened gem at the normal maximum will not continue to gain experience. The max level is 6.
Add or subtract 1-20 quality. Gems can have up to 23% quality this way.
Note that it has risks to make the awakened gem becoming worse.