Saelices, L.; Afrin, S.; Nguyen, B. A.; Bassett, P. T.; Fernandez Ramirez, M. d. C.; Pedretti, R.; Villalon, L.; Kelly, C.; Lopez, C.; Madabushi, M.; Zhou, A.; Reis, I.; Taipa, R.; Evers, B. M.

Amyloid deposition in the central nervous system is increasingly recognized in transthyretin (ATTR) amyloidosis, particularly in patients with prolonged survival following liver transplantation or disease-modifying therapies. However, the structural basis of transthyretin aggregation in the brain remains unknown. Here we determine cryo-electron microscopy (cryo-EM) structures of ex vivo brain-derived ATTR fibrils from patients carrying the ATTRv-V30M and ATTRv-V30G variants. Both fibrils adopt folds distinct from those previously reported in peripheral tissues and the vitreous humor. V30M fibrils exhibit a continuous ordered core spanning residues Pro11-Asn124, whereas V30G fibrils consist of a substantially reduced ordered core, revealing pronounced structural divergence even within the same tissue environment. Despite this diversity, comparative analyses identify conserved regions across ATTR fibrils, including a segment implicated in transthyretin aggregation and targeted for diagnostic and therapeutic development. These results provide direct evidence that local tissue context can shape amyloid fibril architecture in human disease.