How were subsets in other diseases identified?

There are 4 types of multiple sclerosis. How was it discovered that there were 4 types?

It's alo well known that there are two types of diabetes.

 

I just looked this up.

https://mssociety.ca/about-ms/types:

Four disease courses have been identified in multiple sclerosis: clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and secondary progressive MS (SPMS)

 

There are many types of Diabetes if you include all subclassifications of Diabetes 3. You were probably referring to Diabetes 1 and 2. At least, there is an ongoing movement in the medical community to classify rare and hereditary diseases of the sugar metabolism as well as early-onset Alzheimer's as Diabetes 3.

Theoretically, CFS also involves pathology with glycolysis, would hence also meet the criteria.

 

MS and diabetes both show differences because doctors follow a lot of different patients over the years and see how the disease progresses. They can pick out groups easily.

ME patients are hidden from medicine.