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Kidney Week

Abstract: PO0413

Type 3 Renal Tubular Acidosis in Association with a Pelvic Kidney

Session Information

Category: Trainee Case Report

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Singh, Prince, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Erickson, Stephen B., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Sy-Go, Janina Paula Tiulentino, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Gregoire, James Robert, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
Introduction

The association of renal tubular acidosis (RTA) from carbonic anhydrase isoenzyme II (CA II) deficiency, cerebral calcifications and osteopetrosis is known as marble brain disease

Case Description

21-year-old woman with a medical history of multiple fractures since childhood, recurrent episodes of nephrolithiasis and, renal tubular acidosis (RTA), presented to establish care at our clinic. Genetic testing had revealed she had CA II gene mutation. Her brother had the same condition but her sisters were healthy. Her medication included potassium citrate and vitamin D3.
Laboratory assessment revealed the following: serum Na+ 143 mmol/L, K+ 3.9 mmol/L, Cl- 109 mmol/L, HCO3 21 mmol/L, creatinine 0.73 mg/dl, Ca2+ 9 mg/dl, PO43- 4.4 mg/dl, vitamin D 7.6 mg/dl. Urine pH was 6. CT urogram revealed a normal right kidney and an ectopic left kidney with numerous small stones. (Figure 1). Spine X rays showed osteopetrosis of vertebral endplates and MRI brain showed calcifications in basal ganglia. Pyelolithotomy of the pelvic stone was performed and stone analysis revealed 90% calcium phosphate and 10% calcium oxalate. 24-hour urine showed a low urine citrate with low urine volume. Thus the findings were consistent for RTA with low serum bicarbonate, low urine citrate and calcium phosphate predominant stones.

Discussion

CA II deficiency syndrome is a rare autosomal recessive disorder that results in Type 3 RTA (combined proximal and distal RTA). Pelvic kidneys, which result from a failure of mesonephros to ascend normally during early gestation, are prone to urolithiasis due to poor urinary drainage. In our patient RTA, along with altered urine flow due to pelvic kidney predisposed to nephrolithiasis.

Ectopic (pelvic) left kidney with multiple stones with a normal looking right kidney