SERUM AMYLOID-P COMPONENT SCINTIGRAPHY IN FAMILIAL AMYLOID POLYNEUROPATHY - REGRESSION OF VISCERAL AMYLOID FOLLOWING LIVER-TRANSPLANTATION

Familial amyloid polyneuropathy (FAP) associated with transthyretin (T TR) mutations is the commonest type of hereditary amyloidosis. Plasma TTR is produced almost exclusively in the liver and orthotopic liver t ransplantation is the only available treatment, although the clinical outcome varies. Serum amyloid P component (SAP) scintigraphy is a meth od for identifying and quantitatively monitoring amyloid deposits in v ivo, but it has not previously been used to study the outcome of visce ral amyloid deposits in FAP following liver transplantation. Whole bod y scintigraphy following injection of iodine-123 labelled SAP was perf ormed in 17 patients with FAP associated with TTR Met30 and in five as ymptomatic gene carriers. Follow-up studies were performed in ten pati ents, eight of whom had undergone orthotopic liver transplantation 1-5 years beforehand. There was abnormal uptake of I-123-SAP in all FAP p atients, including the kidneys in each case, the spleen in five cases and the adrenal glands in three cases. Renal amyloid deposits were als o present in three of the asymptomatic carriers. Follow-up studies 1-5 years after liver transplantation showed that there had been substant ial regression of the visceral amyloid deposits in two patients and mo dest improvement in three cases. The amyloid deposits were unchanged i n two patients. In conclusion, I-123-SAP scintigraphy identified unsus pected visceral amyloid in each patient with FAP due to TTR Met30, The universal presence of renal amyloid probably underlies the high frequ ency of renal failure that occurs in FAP following liver transplantati on. The variable capacity of patients to mobilise amyloid deposits fol lowing liver transplantation may contribute to their longterm clinical outcome.