Depending on what you’re trying to do, you can use InstancedStructs which were introduced in 5.something and moved into the Engine in 5.5.
I say depending because you can get sort of the behavior of inheritance, but you still can’t do direct inheritence with blueprint structures. Like you can’t actually share members up and down the heirarchy. But you can get the behavior when passing around instances, cast to specific types and that sort of thing.