[Aged onset of amyloidosis caused by transthyretin gene mutations]

We have identified that familial amyloid polyneuropathy with middle age onset results from missense mutations of the transthyretin gene. In the present study, we investigated molecular abnormalities of transthyretin in elderly patients with cardiac amyloidosis or amyloid polyneuropathy, using DNA sequencing and protein sequencing. We detected 5 cases of transthyretin-related cardiac amyloidosis using immunohistochemical techniques. All of them had late-onset, mild or no peripheral neuropathy or autonomic dysfunctions, and no family history. Three had transthyretin Met30 and two transthyretin Ile50. We also found 15 patients with transthyretin-related amyloid polyneuropathy. All of them had late-onset and no contributory family history. Twelve had transthyretin Met30, two transthyretin Ile50, and one transthyretin Ser109. Clinical manifestations and sequencing procedures of six representative patients were also presented. Molecular investigation of transthyretin is needed for elderly patients with etiology-unknown cardiac amyloidosis or amyloid polyneuropathy even if there is no family history of amyloidosis.