Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders

Disorders of the renal phosphate transporters

Renal phosphate transporters are sodium-coupled transporters located in the apical membrane of proximal tubular cells. They play an important role in phosphate regulation.

Pathogenesis

Under physiological conditions phosphate is filtered in excess, so the body needs to reclaim large amounts of phosphate to keep the body content stable (60-80%). This resorption is accomplished by renal phosphate transporters. Inactivation of those transporters may result in excessive urinary phosphate loss and bone destruction ensue.

Renal phosphate transporters are located in the proximal tubule. The figure below shows its distribution along the segments. While the transporter SLC34A1 can be found in all three segments the other two are localized in the first two segments only.

G cluster0 cluster1 Glomerulum cluster2 Proximal tubule cluster3 Loop of Henle l10 SLC34A1 g10 G l20 SLC34A3 g20 G l30 SLC20A2 g30 G p11 S2 g10->p11 p21 S2 g20->p21 p31 S2 g30->p31 p12 S3 p11->p12 p22 S3 p21->p22 p32 S3 p31->p32 p13 S3 p12->p13 p13->h11 p23 S3 p22->p23 p23->h21 p33 S3 p32->p33 p33->h31
Lokalisation der Phosphattransporter in der Niere

Under physiological conditions theTrasnporter SLC20A2 has no effect on phosphate handling as dysfunction can be easily compensated by the other two transporters. Therefore no mutation with bone or kidney phenotype is known so far. However, it seems plausible that variation in this gene too may contribute to a phenotype caused by mutations in other genes.

Systematic

Hypophosphatemic bone and kindney disease
Disorders of the renal phosphate transporters
Hypophosphatemic rickets with hypercalciuria
SLC34A3
Idiopathic basal ganglia calcification 1
SLC20A2
Nephrolithiasis/osteoporosis, hypophosphatemic, 1
SLC34A1
Nephrolithiasis/osteoporosis, hypophosphatemic, 2
SLC9A3R1
FGF23-induced hypophosphatemic rickets
Fanconi-type hypophosphatemic rickets
Hypophosphatemic rickets with hyperparathyroidism
Osteoglophonic dysplasia
Raine syndrome
X-linked dominant hypophosphatemic rickets

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Update: April 29, 2019