The user's Reputation tab gives us some clues. 100 rep for association bonus, and then as @Journeyman Geek has suggested, reputation which was obtained from a deleted question, which hasn't been removed via the SQL maintenance tasks.
We can use the Wayback Machine to see what the question was, and how the reputation was allocated. Here's a snapshot of the ...
Looks like an account merge with a much older account.
I'm too sleepy to actually do more digging, but the rep seems to be from an old question from waaaaaay back, deleted but around enough to keep the rep.