Changes in renal function in patients with familial amyloid polyneuropathy treated with orthotopic liver transplantation

Background. Familial amyloid polyneuropathy (FAP) is an autosomal dominant disease caused by a point mutation in the gene encoding transthyretin, which is secreted by the liver. Orthotopic liver transplantation (OLT) has been proposed to prevent disease progression. Little is known about long-term changes in renal function and lesions after OLT. Methods. The renal function of 33 patients with FAP was evaluated (proteinuria, serum creatinine, creatinine clearance) before OLT and over a period of at least 5 years afterwards. A pre-transplantation renal biopsy was performed in 14 patients and a follow-up biopsy in eight patients. Results. Before transplantation, mean serum creatinine concentration was 86 mumol/l (47-126 mumol/l) and creatinine clearance was 71.9 +/- 31.6 ml/min/1.73 m(2). Proteinuria was detected in 54% of patients (0.3-4 g/day). Pre-transplant renal biopsies (n = 14) revealed glomerular, tubular and vascular amyloid deposits in 90, 58 and 66% of patients, respectively. Eleven patients (33%) died after OLT. Death occurred most frequently in patients having weight losses >7 kg (P < 0.05). After transplantation, 25 patients (76%) suffered acute renal failure but only one required dialysis. One month after transplantation, the mean serum creatinine concentration was 134.1 +/- 73 mumol/l and remained constant during follow-up. Eight patients underwent a second renal biopsy 2 years after transplantation. No significant changes in deposits or renal toxicity due to calcineurin inhibitors were detected. Conclusion. Although liver transplantation in FAP does not affect existing renal amyloid deposits, it prevents the progression of renal disease.