Inhibitors of the renin-angiotensin-aldosterone system and sodium-glucose cotransporter protein 2 may serve as fundamental treatments for both IgA nephropathy and DDD; however, according to KDIGO guidelines, immunosuppressive therapies are applicable for patients with moderate to severe disease (characterized by proteinuria exceeding 1 g/day, hematuria, or diminished renal function persisting for at least 6 months) [13]. Here, REN is linked to Dowling-Degos disease 1.