In patients with nephrocalcinosis (n=55; 44 children and 11 adults), we identified 18 (33%) patients with biallelic class IV or V variations, mostly in CYP24A1 (n=25/28) and also in SLC34A3 (n=3/28); 4 adults with biallelic CYP24A1 mutations presented chronic kidney disease (CKD-EPI<60mL/min). The gene discussed is SLC34A3; the disease is chronic kidney disease.