Familial amyloidotic polyneuropathy (ATTR Ser50Ile): the first autopsy case report

Abstract 

We report an autopsy case of a pedigree of familial amyloidotic polyneuropathy (FAP) with a mutation of isoleucine-50 transthyretin (ATTR Ser50Ile). A 47-year-old man started developing severe diarrhea and weight loss at age 41 years, followed by urinary incontinence, autonomic-nervous-system abnormalities and serious heart failure; the diagnosis of FAP (ATTR Ser50Ile) was made on the basis of genetic, histochemical and immunohistochemical analysis. Six years after the initial symptoms, he died of septic shock. Autopsy revealed suppurative peritonitis, perforation of the sigmoid colon and marked systemic amyloid deposition. The total amount of amyloid deposited in the heart was greatly increased and was much lower in the thyroid gland and kidneys compared with amyloid deposits in ordinary FAP (ATTR Val30Met). Amyloid deposition in peripheral vessel walls was prominent, particularly in lymphatics and veins. His elder sister, 54 years old, started to develop orthostatic hypotension at age 49 years, followed by dysesthesia, diarrhea and severe congestive heart failure. Endomyocardial biopsy revealed severe TTR–amyloid deposition; ultrastructural examination demonstrated that amyloid fibrils were deposited disproportionately and extended radially around microvessels. These characteristic patterns of systemic amyloid deposition and distinct clinical manifestations, especially in the cardiovascular system, are considered to be a characteristic feature of ATTR Ser50Ile amyloidosis.