As a kind of ER/mitochondria-related disease, WFS2, a subtype among WFS (featured in diabetes insipidus, diabetes, optic atrophy, and deafness [DIDMOAD]), has been linked to the recessive mutation of CISD2. WFS2 may clinically manifest as diabetes mellitus, optic atrophy, and a bleeding tendency [76]. The gene discussed is CISD2; the disease is diabetes mellitus.