1970’s Movie – Clinic experiments on girl w/supernatural powers?

This movie has to be from the 1970’s. About a young girl about 13 who has supernatural powers. Her parents take her to a clinic to see what her powers are all about and the clinic steals her and won’t give her back. The clinic is full of girls like this and they do experiments on all of them to see how they’ve gotten their powers and how they can harness the powers for themselves? The movie was named after the girl, her first name and I cannot remember it for my life. The parents try to get her out, but cannot. The girl is angry and uses her powers against her captors. It’s so good! Please help! Everyone was in white lab coats and the girls were in long white robes I think. Very creepy and cool! American, I believe.