Normal mis barring is a husbandry problem. Over barring like picassos and snowflakes is genetic. I haven't dealt with naked clowns, so I don't know about those.
When I first started breeding/raising clowns in the 90's my first batches contained a lot of misbarrs and jaw/gill deformities. Once I got the a filtration/water change schedule figured out and got better at culturing food, I was able to pretty much eliminate misbarring and head deformities all together.