Clinical practice guidelines suggest that persistence of eGFR <60 mL/min/1.73 m2 with a duration of more than 3 months might be considered CKD; the different cystatin C prediction equations resulted in different prevalence of CKD detected (8.8% to 16.1%), which varies with the prevalence detected by the creatinine only equation (7%) [1]. The gene discussed is CST3; the disease is chronic kidney disease.