Value of renal biopsy in the prognosis of liver transplantation in familial amyloid polyneuropathy ATTR Val30Met patients.

Liver transplantation for familial amyloid polyneuropathy (FAP) patients has been carried out worldwide and the outcomes seem to be promising. To clarify the severity of amyloid deposits on visceral organs, we evaluated the histopathological findings of biopsied renal and sural nerve specimens in 13 FAP patients with ATTR Val30Met by quantitative analysis, and compared them with the outcome of transplantation. Renal dysfunction with proteinuria seemed to correlate with the degree of amyloid deposits in glomeruli, not with that in medullary tissues. The severity of renal amyloid deposition did not consistently parallel that of myelinated nerve fiber loss in sural nerve. Three patients with proteinuria and severe amyloid deposits in glomeruli were considered to be unsuitable for transplantation. Ten patients underwent living donor liver transplantation and three resulted in unfavorable outcomes. These three had heavy amyloid deposits on renal tissues, especially in glomerular areas, but the severity of myelinated nerve fiber loss in their sural nerves was very similar to that in patients who made a good recovery. The prognosis after operation might be closely related to the severity of amyloid deposits in renal glomeruli. Renal biopsy is, therefore, recommended when determining the indications and contraindications for liver transplantation in FAP patients, although this biopsy is not routinely required.