In FBD a point mutation, while in FDD a decamer duplication insertion, abolishes the stop codon of the BRI2 gene resulting in C‐terminally elongated precursor proteins (Ghiso et al., 2000, 2001, 2006; Rostagno et al., 2005, 2010; Vidal et al., 2000). The gene discussed is ITM2B; the disease is ADan amyloidosis.