A real rarity in this age. To have remained a human through all the planets changes you would have needed to be lucky enough to have been in a bunker that was not in an area high in magic which bunkers were never designed to withstand and for it to have been well supplied enough to have survived many generations. Mind you, given some of the mutations out there, would you really be lucky to have not mutated.
Before “natural” mutations started appearing out in the wild, humans had already started forcing mutations upon themselves. Generally these were specifically tailored towards a particular role or task. Most of these mutations either just increased natural abilities of homo sapien or introduced abilities from other pre-war species. For example;
*Soldiers bred to be faster/stronger.
*Assassins with chameleon pigmentation, claws and poison glands.
*Scientists bred to make use of more of their brain at one time.
For the most part these “GenMods” remain essentially human looking except in a few examples such as altering hair follicles to create keratin armour plating.
“Natural Mutant” came about more as a by product of the changing world. Their change came about through radioactive, biological or chemical weapons, exposure to extreme magikal conditions or a combination thereof. Most often these mutations led to horrific disfigurement, and other generally negative effects resulting in creatures closely resembling zombies or vampires or beast/man hybrids. However in some cases mutations led to something more.
For example a group in Tir known as Fae mutated to include Gravinite into their bone structure and grow wings to appear much like faeries. It is believed that some kind of racial memory affected the way they mutated.