Board Thread:Rebirth: Applications/@comment-4080775-20141129192059/@comment-4080775-20141202165305

The Eight Gates don't focus on Tenketsu, but by manipulating the number of tenketsu before the activation of the technique allows the user to mold their chakra in unique ways, allowing for advanced techniques with the Eight Gates.

Bycause Pressure Points / Tenketsu Points are linked to muscles themselves, they are able to manipulate the amount by generating new muscle and changing the shape of their bodies.

This can also work to their disadvantage too, against the Byakugan, and dojutsu / shinobi capable of seeing them, as if they are struck, and if they have less tenketsu, it makes it much easier to take down and disable the users us of their KG. I wouldn't call it a mutation, it's just an extension of muscle manipulation.