Help in determining what might be wrong?

Ok I need some help with my daughter. She is 10 years old and in the last two years has more than doubled her weight. Her eating patterns have not changed. Her exercise has increased. She plays softball, swims on a team and dances. The doctor has run thyroid tests and sugar tests and both have come back normal. Someone mentioned to me that there is another thyroid test that is done in Canada but that they don't tend to run in the US because it is so expensive. Has anyone else run into this problem and can help point me in the direction we need to go to get the right tests run and help her. I hate to see her upset about her weight. I also need to know that I have exhausted every route to help her. I don't know if it will help relate it to your situation but she also suffers from nocturnal inertia and some impulsivety problems. Any constructive help would be greatly appreciated