Primary hyperoxaluria remains undiagnosed in patients with hyperoxaluria and recurrent urolithiasis

Primary hyperoxaluria (PH) is a metabolic disorder caused by deficiency of either the liver-specific enzyme alanine:glyoxylate aminotransferase (AGT) for PH type 1 (PH1) or glyoxylate reductase/hydroxypyruvate dehydrogenase (GR/HPR) for PH type 2 (PH2). PH increases endogenous oxalate production, leading to the development of renal stones and nephrocalcinosis, which may result in end-stage renal disease (ESRD) (1). The 1st step in the diagnostic process involves measurement of urinary oxalate, glycolate, and/or l-glycerate, followed by enzymatic analysis of AGT (in liver) or GR/HPR (in lymphocytes), or genetic testing of the AGXT gene for PH1 or the GRHPR gene for PH2. Extensive metabolic screening is rarely performed in adults who present with stone disease because PH disease presentation usually occurs in childhood, not in adulthood. Nevertheless, more than one-third of PH1 is diagnosed in adult patients in ESRD (2). Early diagnosis and treatment is of utmost importance in PH, because conservative therapy can prevent renal …