Frontotemporal Dementia (FTD), particularly its behavioural variant (bvFTD), is characterized by progressive disruption of social behaviour resulting from degeneration of frontal and anterior temporal brain networks. While these changes are traditionally interpreted at the level of neural circuitry, emerging evidence suggests that their origins may lie in molecular processes that compromise protein and cellular homeostasis.

A common feature of several neurodegenerative disorders, including FTD, is the involvement of proteins containing repetitive or low-complexity domains, such as tau, TDP-43, and repeat expansions in C9orf72, which are prone to misfolding and aggregation. Such structural repetition may contribute to instability in proteostasis, leading to synaptic dysfunction and large-scale network impairment. In contrast, repetitive motifs in other biological systems, such as glycine–alanine-rich sequences in spider silk spidroins, can produce highly stable and functional macromolecular structures, highlighting the context-dependent outcomes of molecular repetition.

Here, we propose a conceptual framework in which repetitive molecular architecture influences neural network stability, contributing to selective vulnerability of frontotemporal circuits involved in social cognition. This framework suggests that microscale molecular properties may have cascading effects on macroscale behavioural phenotypes in neurodegenerative disease. Although comparisons across biological systems are not mechanistically equivalent, they underscore a broader principle that structural repetition can yield divergent functional outcomes depending on cellular context and regulatory environment.

This perspective integrates molecular biophysics with systems neuroscience and highlights the need for further investigation into how protein-level properties contribute to network dysfunction and behavioural impairment in FTD and related disorders.