Many common diseases are highly heritable, inluding e.g breast cancer and coronary heart disease. Currently patients are only evaluated for monogenic causes of these disorders. However reporting of polygenic risk, i.e. polygenic risk scores has matured. We aim to evaluate the use of polygenic risk scores (PRS) on patient data for implementation in the clinic. We aim to both impute PRS from WGS data and from array data. We will calculate PRS from patient data initially focusing on risk of risk of breast cancer subtypes. We will evaluate models for calculating confidence intervals and prediction intervals and how they relate to genetic ancestry. The main supervisor is Professor Niklas Dahl.