My daughter was diagnosed with this 20 years ago when she was 15. At that time, very little seemed to be understood about it. She became a world wide study of the condition where many doctors from all over the world came to see her. In the end it was a Japanese doctor who diagnosed her.
20 years on, she is free from this condition, however , I was recently diagnosed hypothyroid and we have concerns she may have Hashimotos, as she has many symptoms and has allergies.
So it will be interesting to see if there is some kind of link.