[Transthyretin-its function and pathogenesis].

Transthyretin (TTR) is a transport protein for retinol-binding protein and thyroxin, and works as a rapid turnover protein. Recently, it has been used as a nutrition assessment protein in the assessment of the acute phase nutritional status in various diseases because it contains four tryptophans in the tetramer of the protein and its plasma half life is 1.9 days. However, the wild-type protein and its mutated form become a precursor protein of amyloid fibrils in senile systemic amyloidosis (SSA) and familial amyloidotic polyneuropathy(FAP), respectively. Recent biochemical and pathological studies revealed that instability of the terameric form of TTR by mutation and post-translational modifications leads to amyloid formation in the tissues of SSA and FAP. In the process of TTR amyloid formation, misfolding of TTR, the trigger of amyloid formation, is also induced. For these amyloid formation mechanisms, Cr3+ administration, BSB(FSB) therapy, gene therapy, and antibody therapy are now on-going therapeutic projects for FAP and SSA.