[33] Sequenome genotyping efficiency was also not 100%, thus our experimentally identified rates of variance may slightly over or underestimate true population prevalence. Despite these limitations, this is the largest study to date to examine a disease and control population for IDO1 and IDO2 SNPs. As such, our work adds to recent studies which have examined the links between IDO gene polymorphisms and disease including pre-eclampsia [34] and systemic sclerosis [35] for IDO1, and, for IDO2, relevance in pancreatic cancer [36] and clinical response to antidepressants [37]. The gene discussed is IDO2; the disease is systemic sclerosis.