Which one of the following is not a feature of type I renal tubular acidosis?

Mutations in CA2 and TCIRG1 result in osteopetrosis (in which bones are hard but brittle) and renal tubular acidosis. Ref: Robbins basic pathology 9th edition pg no: 801 Nephrocalcinosis is a diffuse deposition of calcium salts in renal tissue in a number of renal diseases, in hypercalcemia, hyperphosphataemia and renal tubular acidosis Ref: Textbook of pathology Harsh Mohan 6th edition page 684.