Orphan Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH) (OMIM: 241530; ORPHA: 157215) with an autosomal recessive mode of inheritance occurs with an estimated prevalence of 1: 250,000 in the child population. HHRH was first described by M. Tieder, et al. (1985). The syndrome is caused by heterozygous or homozygous mutations in the SLC34A3 gene mapped to chromosome 9q34.3, which encodes a type II sodium phosphate cotransporter (NaPiIIc). Mutations result in loss of NaPi-IIc function and impairment of phosphate reabsorption in the proximal renal nephron. HHRH is characterized by a decrease in phosphate reabsorption in the proximal nephron tubules, manifested by hyperphosphaturia, hypercalciuria, hypophosphatemia, an increase in the concentration of 1,25(OH) 2D3, a decrease in parathyroid hormone (PTH) circulating in the blood, osteomalacia, inhibition of growth, low corrosiveness, low corrosiveness. The article presents the characteristics of the phenotype and genotype of HHRH, diagnostic criteria and treatment strategy. A description of a clinical case of HHRH with hypercalciuria, nephrocalcinosis and urolithiasis due to mutation of the SLC34A3gene is presented.