illnesses like bipolar have been debated as much as other things as far as "nature vs nurture" goes... but twin studies suggest that a person is born with the susceptibility to bipolar but is not guaranteed to develop it. That part is then up to their environment and nurturing.

Bipolar is a broad thing now.. from cyclothemia to bipolar I. I truly, truly believe that someday it won't exist as it is termed right now and we will have several new, more accurate dx's. i think most bipolars have many of the traits... that later, when they intensify become classed as symptoms. Are we all bipolar? Unless they invent a blood test i think it will always be a game of labels.

so... to answer your q:
no, it isn't possible according to the DSM to be born symptomatic from the get-go.... but we know that some of us are despite what the DSM says.

clear as mud