To overcome these limitations, it is mandatory to examine whether miR106b, circulating ACE2, angiotensin II, or angiotensin 1-7 levels can better reflect the benefits of vitamin D/calcitriol (analog) interventions and serve as biomarkers to optimize the reno-protective effects of vitamin D therapy in CKD compared to circulating 25(OH)D levels. The gene discussed is ACE2; the disease is chronic kidney disease.