The defect RTA-I prevents the distal tubule from generating, or maintaining, the normal 900:1 hydrogen ion concentration gradient across its wall.
Systemic acidosis results in calcium resorption from bone and hypercalciuria.
Nephrocalcinosis and urinary stones are common, being the result of:
- alkaline urine: calcium phosphate tends to precipitate out in alkaline urine
- low urinary citrate excretion: citrate chelates calcium and reduces precipitation
Hypokalaemia results from:
- a lack of intraluminal hydrogen ions, resulting in exchange of potassium for luminal sodium
- increased sodium losses, resulting in secondary hyperaldosteronism and hence hypokalaemia
Last reviewed 01/2018