Several of these discoveries have suggested etiologic pathways not previously implicated in these diseases, such as the autophagy pathway in inflammatory bowel disease (48), the complement pathway in macular degeneration (23), and the HLA-C locus in control of viral load in HIV infection (49). Of considerable interest in determining pathophysiology have been variants or regions implicated in multiple diseases, such as the 8q24 region in prostate, breast, and colorectal cancers and the PTPN2 gene in type 1 diabetes and Crohn’s disease (9).
