Since the ALD-linked Chr 8 locus overlaps with T1D-protective Idd22 (Mathews et al., 2003), and mt-Nd2a was also associated with T1D (Mathews et al., 2005), the interaction between mt-Nd2 and Chr 8 appears to regulate β-cell survival during development of diabetes. The gene discussed is MT-ND2; the disease is diabetes mellitus.