Primary Hyperoxaluria Type I: An Underestimated Cause of Nephrocalcinosis and Chronic Renal Failure in Saudi Arabian Children

Abstract

Primary hyperoxaluria type I (PHI) is a rare metabolic disease caused by deficiency or abnormalities of the peroxisomal enzyme alanine-glyoxylate aminotransferase. In the majority of patients, the clinical expression of PHI is characterized by recurrent calcium oxalate urolithiasis, nephrocalcinosis and renal failure. Sixteen children aged 5 months to 14 years were diagnosed as PHI over a 10-year period ending in June 1997. The diagnosis was established by quantitative urinary oxalate excretion, or by a high urine oxalate/creatinine ratio on spot urines. The majority of patients had nephrolithiasis (13/16) and/or nephrocalcinosis (12/16). Four patients already had advanced chronic renal failure at the time of diagnosis. Altogether, PHI accounted for 20% of nephrocalcinosis and 6% of end-stage renal disease. Two patients had a complete response to pyridoxine therapy, while four patients had a partial response. Eight patients underwent organ transplantation, three underwent kidney transplantation, three received combined liver/kidney transplantation for end-stage renal disease, and two received isolated preemptive liver transplantation. Combined organ transplantation provided the best long-term results.