CST3 and congenital rubella syndrome: We address (i) the epidemiology and clinical significance of cardiorenal overlap across CRS/CKM, (ii) functional phenotypes defined by inactivity, low exercise capacity, sarcopenia/frailty, and disability, (iii) rehabilitation effects on physical function and renal trajectories, including renal endpoint validity (creatinine vs. cystatin C), and (iv) prognostic implications and evidence gaps.