CLINICAL EXPRESSION AND LONG-TERM OUTCOMES OF PRIMARY HYPEROXALURIA TYPE-1 AND TYPE-2

Primary hyperoxaluria, types 1 and 2, are rare disorders. Much of the information in the literature has been derived from case reports and d ata registries limited to patients requiring dialysis and/or transplan tation. We present a single-center experience of 42 patients and 437 p atient years of clinical experience with primary hyperoxaluria. Median age at onset of symptoms for patients with type 1 PH was 9 years, typ e 2 15.7 years. Sixty-four percent of the patients were less than 15 y ears of age at onset of symptoms. There was no correlation between uri ne oxalate excretion rates and age at onset of symptoms. Stone forming activity was greater in patients with type 1 PH than type 2. Ten pati ents presented initially with ESRD, and an additional seven developed ESRD during the course of follow-up. ESRD occurred in 54 percent of th e patients with type 1 and 12 percent of patients with type 2 PH. Eigh t patients received nine renal allografts, five patients received comb ined kidney/liver transplants, and one patient received a hepatic allo graft only. Ten of the transplanted patients were surviving at the tim e of the most recent follow up. Eight of them have functioning renal g rafts and four have functioning hepatic grafts. There have been no dea ths since 1988 among the 32 patients followed since that time. These d ata may suggest a broad range of clinical expression of primary hypero xaluria. With current management strategies, outcomes are more favorab le than has been reflected in previous literature.