TTR CAA was not accompanied by amyloid deposition in the parenchyma outside the subpial and subependymal regions (either cerebrum, cerebellum, brainstem, or spinal cord), unlike what is seen in the more common sporadic Aβ and some rare forms of familial CAAs, including hereditary cerebral hemorrhage with amyloidosis of Icelandic type (HCHWA-I), familial British dementia (FBD), and familial Danish dementia (FDD) CAA [25]. This evidence concerns the gene TTR and ITM2B amyloidosis.