Clinical aspects of the phosphate transporters NaPi-IIa and NaPi-IIb: mutations and disease associations

Eleanor Lederer, Carsten A. Wagner

Research output: Contribution to journalReview articlepeer-review

21 Scopus citations


The Na + -dependent phosphate transporter NaPi-IIa (SLC34A1) is mostly expressed in kidney, whereas NaPi-IIb (SLC34A2) has a wider tissue distribution with prominent expression in the lung and small intestine. NaPi-IIa is involved in renal reabsorption of inorganic phosphate (Pi) from urine, and patients with biallelic inactivating mutations in SLC34A1 develop hypophosphatemia, hypercalcemia, hypercalciuria and nephrocalcinosis, and nephrolithiasis in early childhood. Monoallelic mutations are frequent in the general population and may impact on the risk to develop kidney stones in adulthood. SNPs in close vicinity to the SLC34A1 locus associate with the risk to develop CKD. NaPi-IIb mediates high-affinity transport of Pi from the diet and appears to be mostly important during low Pi availability. Biallelic inactivating SLC34A2 mutations are found in patients with pulmonary alveolar microlithiasis, a lung disease characterized by the deposition of microcrystals. In contrast, no evidence for disturbed systemic Pi homeostasis has been reported in these patients to date. Nevertheless, NaPi-IIb-mediated intestinal Pi absorption may be a target for pharmaceutical interventions in patients with chronic kidney disease and Pi overload.

Original languageEnglish (US)
Pages (from-to)137-148
Number of pages12
JournalPflugers Archiv European Journal of Physiology
Issue number1
StatePublished - Jan 31 2019
Externally publishedYes


  • Hyperphosphatemia
  • Hypophosphatemia
  • Nephrolithiasis
  • Phosphate metabolism
  • Pulmonary alveolar microlithiasis

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)


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