TTR and amyloidosis: Among these components, transthyretin, as a homotetrameric protein which is mainly synthesized in the liver, the choroid plexus and the retina, is implicated in several amyloid pathologies including familial amyloid polyneuropathy, familial amyloid cardiomyopathy, senile systemic amyloidosis and central nervous system selective amyloidosis4–6.