CISD2 and diabetes mellitus: WS2, a rarer manifestation that has been linked to recessive CISD2 mutations (Amr et al, 2007), shares many clinical features with WS1 including diabetes mellitus, but distinctively presents with gastrointestinal complications like peptic ulcers and bleeding tendencies without diabetes insipidus (Al-Sheyyab et al, 2001; Rosanio et al, 2022; Urano, 2016).