Skip to main content
. Author manuscript; available in PMC: 2021 Jan 8.
Published in final edited form as: Calcif Tissue Int. 2019 Nov 25;108(1):16–31. doi: 10.1007/s00223-019-00636-8

Table 1.

Characteristics of phosphate transporters

SLC34 Family (Type II Na/Pi cotransporter) SLC20 Family (Type III Na/Pi cotransporter)
NaPi-2a NaPi-2b NaPi-2c PiT-1 PiT-2
Human gene SLC34A1 SLC34A2 SLC34A3 SLC20A1 SLC20A2
Gene locus Chromosome 5 Chromosome 4 Chromosome 2 Chromosome 2 Chromosome 8
Predominant transported species of Pi HPO42- HPO42- HPO42- H2PO4- H2PO4-
Na+:Pi stoichiometry 3:1 3:1 2:1 2:1 2:1
Ion transport property Electrogenic Electrogenic Electroneutral Electrogenic Electrogenic
Major organ expression Kidney Intestine, lung Kidney Ubiquitous expression Kidney, neuron
Genetic disorders associated with inactivating mutation

  • Infantile hypercalcemia 2

  • Fanconi renotubular syndrome 2

  • Hypophosphatemic nephrolithiasis/osteoporosis 1

 Pulmonary alveolar microlithiasis Hereditary hypophosphatemic rickets with hypercalciuria Unknown Familial idiopathic basal ganglia calcification (Fahr’s disease)

Abbreviations: NaPi, sodium-phosphate cotransporter; PiT, phosphate transporter