We recently carried out a genetic study of antibody deficiency associated primary immune deficiency (AD-PID), that supported previous evidence for a role for common genetic variants in modulating disease risk. Across the whole genome we found that these common variants overlapped with other immune-mediated diseases (IMD) more than we would expect by chance. Building on these observations this project will examine whether polygenic risk scores of IMD are useful in gaining a further understanding of the genetic architecture of PID, as this might shed light on underlying disease pathogenesis.