Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders

Renal tubular acidosis

Renal tubular acidosis is a metabolic acidosis caused by renal tubular dysfunction. It is characterized by normal glomerular filtration rate, hyperchloremia, and a normal plasma anion gap. Based on pathophysiology, location, and genetics several types may be distinguished.

Classification

The traditional classification of renal tubular acidosis (RTA) is based in pathophysiological findings and localization of the tubular defect.

Type Name
1 distal RTA
2 proximal RTA
3 combined proximal and distal RTA
4 hyperkalemic RTA

Pathogenesis

Very different defects in tubular transport, metabolism and signal transduction can result in renal tubular acidosis. The filtered bicarbonate reabsorbed fundamentally in the proximal tubule. This way defects in bicarbonate reabsorption are classified as proximal tubular acidosis. The acidification occurs in the distal nephron. That's why defects in acidification are called distal tubular acidosis. Of course there can be mixed forms. Defects in the adosterone signal transduction that result in hypoaldosteronism can cause the hypokalemic form of renal tubular acidosis.

Symptoms

Acidosis
Hyperchloremic metabolic acidosis is the hallmark of RTA.

Systematic

Disorders of tubular solute transport
Genetic disorders of proximal tubular function
Hereditary Salt-wasting tubulopathies
Inherited disorders of calcium balance
Liddle syndrome
Nephrogenic diabetes insipidus
Pseudohypoaldosteronism
Renal tubular acidosis
Combined renal tubular acidosis 3 with osteopetrosis 3
CA2
Distal renal tubular acidosis (autosomal dominant)
SLC4A1
Distal renal tubular acidosis (autosomal recessive)
ATP6V0A4
Distal renal tubular acidosis with deafness (autosomal recessive)
ATP6V1B1
Proximal renal tubular acidosis
SLC4A4
Renal tubular acidosis with arthrogryposis
Arthrogryposis, renal dysfunction, and cholestasis 1
VPS33B
Arthrogryposis, renal dysfunction, and cholestasis 2
VIPAS39

References:

1.

Igarashi T et al. (2002) Unraveling the molecular pathogenesis of isolated proximal renal tubular acidosis.

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2.

None (2002) Inherited distal renal tubular acidosis.

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3.

Santos F et al. (2017) Renal tubular acidosis.

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4.

Yaxley J et al. (2016) Review of the Diagnostic Evaluation of Renal Tubular Acidosis.

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5.

OMIM.ORG article

Omim 179800 [^]
6.

Orphanet article

Orphanet ID 18 [^]
7.

Wikipedia article

Wikipedia EN (Renal_tubular_acidosis) [^]
Update: April 29, 2019