Nephrocalcinosis can result from some of acquired causes as well as being a part of the symptomatic complex of hereditary diseases. Despite monogenic causes of nephrocalcinosis being rare they nevertheless represent a significant disease burden with early onset of symptoms and a risk for the chronic kidney disease development. The purpose of this research was to describe the etiological characteristics and clinical picture of children with nephrocalcinosis as well as to assess its progression and impact on further decline in renal function. Methods used: a retrospective-prospective cohort study of 85 children with nephrocalcinosis was conducted on the basis of the National Medical Research Center for Children’s Health (Moscow, Russia) in 2012-2023. Results: the median age of the nephrocalcinosis detection was 1.5 [0.3; 4.4] y/o. Median observation duration was 2.5 [1.0; 5.0] years. For 37 (63%) there was a causative mutation responsible for the development of the disease associated with nephrocalcinosis diagnosed. Mutations in the CYP24A1, CLCN5, AGXT and HPRT1 genes had predominated. Further nephrocalcinosis progression had no significant effect on kidney function within a 2-year follow-up. Conclusion: nephrocalcinosis may be a part of the diseases with a high risk for progression and poor renal prognosis. Early diagnosis of the nephrocalcinosis cause is important for obtaining accurate prognostic information and timely therapy initiation.