Recently, we demonstrated that SMSr interacted with the δ isozyme of DG kinase (DGKδ) (22, 23, 24), which is involved in the pathogenesis of type 2 diabetes (25, 26), obsessive–compulsive disorder (27, 28), and epidermal growth factor–dependent cell proliferation (29), via their sterile α motif domains (SAMDs) (30). Here, SAMD8 is linked to type 2 diabetes mellitus.