Not sure that diseases belong to institutes. Grants are applied to the institutes the most closely matches the subject of the grant, and many diseases are funded by many different institutes.
Koroshetz stated that his institute (NINDS) covers about 400 diseases. ME/CFS used to be in the infectious disease institute. I'm not sure the year when it was moved out of an institute and placed into the Office of Women's Health.
In this interview, Dr. Nahle references Dr. Francis Collins' statement that ME/CFS is one the "most challenging" of illnesses.
Dr. Collins quote:
https://www.nih.gov/news-events/new...ic-encephalomyelitis/chronic-fatigue-syndrome
Dr. Collins quote:
https://www.nih.gov/news-events/new...ic-encephalomyelitis/chronic-fatigue-syndrome
NIH also is moving oversight of ME/CFS research from the Office of Research on Women’s Health to the National Institute of Neurological Disorders and Stroke (NINDS). http://www.sciencemag.org/news/2015/10/nih-refocuses-research-chronic-fatigue-syndrome