I am trying to calculate polygenic risk scores (PRS) scores for a new dataset. This dataset does not have all the variants that the PRS score needs. The PRS score I am interested in has 40 variants, but in my dataset only 20 of those variants are present. What is the correct way of assessing the decreased predictive power of the PRS score due to the missing variants?
I assume it is not as easy as summing the effective weights of those variants I have and comparing to the full sum (all variants needed for the PRS).
Thanks a lot and sorry for newbie question!