If one question has been closed by the moderators for some reasons like exact duplicate or out of topic etc then does it causes reputation loss?
Closure doesn't, and deletion doesn't immediately change the headline value displayed on the site, but it will if and when your reputation is recalculated.
This works both ways of course. If your post was down-voted you won't get the reputation back either.
I wouldn't ask for a recalculation too eagerly though, as these things tend to more or less balance out over the long run.
You can see an accurate value by checking the