NAR is not known to involve pancreatic islets, and the joint colocalisation of T1D and NAR association signals with CTSH expression by monocytes suggests that the effects of CTSH reported by Fløyel et al. (27) in islets imply that this gene might exert its effect on T1D by variable expression in multiple cell and tissue types. Here, CTSH is linked to type 1 diabetes mellitus.