disease disease similarity/correlation

Question

[GD]

Suppose, I have two diseases d1, d2 (as a reference, think OMIM entries):

What kind of disease-disease similarities do exists (if any)?

Now, suppose I have a set of diseases: S = {d1, d2, ..., dN} .

What measures of relatedness (if any) do exists?

Answer 1

[Shicheng Guo]

Take a threshold to the correlation coefficient. Disease pair can be consider to be related if the R-square large than that threshold. Here, How to set the threshold you can have dozen choice (some basic, some complicated)