Both Helen Keller and Gregor experience a dramatic change, but the way they occur, and the results are much different.
First, Helen’s transformation occurs slowly and with lots of human care and help. Gregor’s transformation happens overnight, and receives a lack of human care because of it.
Additionally, Gregor’s transformed state, and Helen’s untransformed state are similar in that they are both stuck inside something they do not understand and have no way of communicating their thoughts and feelings.
While Helen Keller’s story ends happily, Gregor’s ends in tragic death.