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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Adolescent, Animals, Computer Simulation, DNA, Humans, Kidney, Kidney Tubules, Proximal, Male, Mutation, Mutation, Missense, Nephrocalcinosis, Oocytes, Opossums, Renal Insufficiency, Sodium-Phosphate Cotransporter Proteins, Type IIa, Transfection, Xenopus laevis.
user
Does loss of function of NaPiIIa cause nephrocalcinosis and possibly kidney insufficiency? Context: Inherited metabolic disorders associated with nephrocalcinosis are rare conditions. The aim of this study was to identify the genetic cause of an Israeli-Arab boy from a consanguineous family with severe nephrocalcinosis and kidney insufficiency. Clinical and biochemical data of the proband and family members were obtained from both previous and recent medical charts. Genomic DNA was isolated from peripheral blood cells. The coding sequence and splice sites of candidate genes (CYP24A1, CYP27B1, FGF23, KLOTHO, SLC34A3 and SLC34A1) were sequenced directly. Functional studies were performed in Xenopus laevis oocytes and in transfected opossum kidney (OK) cells. Our patient was identified as having nephrocalcinosis in utero, and at the age of 16.5 years, he had kidney insufficiency but no bone disease. Genetic analysis revealed a novel homozygous missense mutation, Arg215Gln, in SLC34A1, which encodes the renal sodium phosphate cotransporter NaPiIIa. Functional studies of the Arg215Gln mutant revealed reduced transport activity in Xenopus laevis oocytes and increased intracellular cytoplasmic accumulation in OK cells.
assistant
Our findings show that dysfunction of the human NaPiIIa causes severe renal calcification that may eventually lead to reduced kidney function, rather than complications of phosphate loss. Final Decision: yes