Primary hyperoxaluria type I: An underestimated cause of nephrocalcinosis and chronic renal failure in Saudi Arabian children

Background: Primary hyperoxaluria type I (PHI) is a rare metabolic disease caused by deficiency or abnormalities of the peroxisomal enzyme alanine-gly oxylate aminotransferase. In the majority of patients, the clinical express ion of PHI is characterized by recurrent calcium oxalate urolithiasis, neph rocalcinosis and renal failure. Patients and Methods: Sixteen children aged 5 months to 14 years were diagn osed as PHI over a 10-year period ending in June 1997. The diagnosis was es tablished by quantitative urinary oxalate excretion, or by a high urine oxa late/creatinine ratio on spat urines. Results: The majority of patients had nephrolithiasis; (13/16) and/or nephr ocalcinosis (12/16). Four patients already had advanced chronic renal failu re at the time of diagnosis. Altogether, PHI accounted for 20% of nephrocal cinosis and 6% of end-stage renal disease. Two patients had a complete resp onse to pyridoxine therapy, while four patients had a partial response. Eig ht patients underwent organ transplantation, three underwent kidney transpl antation, three received combined liver/kidney transplantation for end-stag e renal disease, and two received isolated preemptive liver transplantation . Conclusion: Combined organ transplantation provided the best long-term resu lts.