TTR and amyloidosis: Bearing in mind that the major hallmark of TTR amyloidosis is plaque formation, Thioflavin S staining along with hTTR immunohistochemistry (Fig 1A) were used to record and quantify TTR specific amyloid deposition among the three age groups of the V30M C1q KO mice and of the V30M mice expressing endogenous C1q.