EPIDEMIOLOGY OF PRIMARY HYPEROXALURIA TYPE-1

Primary hyperoxaluria type 1 (PH1) always leads to oxalate accumulatio n throughout the body (oxalosis). Currently available epidemiological data only concern patients with end-stage kidney disease requiring ren al replacement therapy (RRT). French nephrologists have been questione d about PH1 patients who were under their care between 1988 and 1992. Exhaustive answers were obtained and 90 cases of PH1 were collected. T he average prevalence rate of PH1 was 1.05/10(6) and its average incid ence rate was 0.12/10(6)/year. The median age at onset was 5 years (0- 63) and initial symptoms involved the urinary tract in 82% of the case s. Half the patients were younger than 10 years at the time of diagnos is on the basis of urine oxalate (89%) +/- urine glycolate (43%) +/- p lasma oxalate (71%) +/- hepatic alanine:glyoxylate aminotransferase ac tivity (48%). At the time of the survey, 36% of patients were on a con servative treatment, 37% were transplanted and 27% were on maintenance haemodialysis; the crude mortality rate was 19% (median age 36 years) . Patients on dialysis started RRT at a median age of 25 years. Transp lanted patients received their first transplant at a median age of 29. 5 years; among those patients with more than year follow-up, 15 receiv ed an isolated kidney transplant (one success), one had an isolated li ver transplant (one success) and 10 combined liver-kidney transplant ( eight successes). These data confirm the rarity of PH1 together with i ts poor prognosis; as shown in the European experience, early combined liver-kidney transplantation seems to be the best therapeutic proposa l.