I’m very glad you wrote. I’m very concerned that the pediatrician or school hasn’t advised her parents to get this child assessed. I can’t make a diagnosis on the basis of a short letter, of course. But I can tell you that what you are reporting suggests that the child may have some level of autism spectrum disorder (ASD). If that is the case, she needs a thorough evaluation and treatment as soon as possible. The earlier treatment begins, the more likely it is to be successful.
It’s not at all unusual for kids with ASD to have a narrow, intense interest in which they are expert, to be socially uncomfortable, and to be unusually hypersensitive to sensory stimuli. Please remember that the intellectual capacity of people on the spectrum varies widely, from intellectual disability to exceptional intelligence. Sometimes the level of intelligence is masked by anxiety and coping behaviors.
You can find more information on the Autism Speaks website: www.autismspeaks.org
I wish you well.