This document discusses the genetic architecture of autoimmune diseases and the potential for finding shared genetic factors across diseases. It acknowledges genes that are common to more than one autoimmune disease and the motivations for exploring an over-arching theme. It then describes the focus on immune-related single nucleotide polymorphisms (SNPs) replicated in genome-wide association studies of rheumatoid arthritis, multiple sclerosis, type 1 diabetes, psoriasis, ankylosing spondylitis and systemic lupus erythematosus. It details the process of data collection and meta-analysis across these studies to identify loci associated with more than one autoimmune disease.