Pernicious anemia (PA) is a complex, autoimmune, multi-factorial disease. Rapid progress has been made in the understanding of susceptibility to a spectrum of other autoimmune diseases through genome wide association studies (GWAS). However, PA has been conspicuous by its absence from this work. Here, we examine the evidence that PA has a significant heritable component through epidemiological evidence and its co-occurrence with other autoimmune diseases. Further, we consider how knowledge of the genetic susceptibility to other autoimmune diseases may provide insight into the etiology of PA.