Hi, Welcome to JustAnswer. I'm a licensed veterinarian and I'll be happy to help. Sorry to hear about your little girls' problems. . .any yours.
Has your girl had a general blood test also? The first thing that comes to my mind is hypothyroidism. This test is often included in a general profile, but not always. Also, if she has had a general blood profile were her other values normal?
I'll be online for the balance of the afternoon here. I'm in California.