BEAN1 (brain expressed associated with NEDD4 1) is a brain-specific gene located on chromosome 16 whose primary function relates to non-coding RNA regulation rather than protein coding. The gene is defined by its association with spinocerebellar ataxia type 31 (SCA31), caused by complex pentanucleotide repeat expansions (TGGAA)n, (TAGAA)n, (TAAAA)n and (TAAAATAGAA)n within a shared intronic region 1. The pathogenic (TGGAA)n repeat is bidirectionally transcribed as a non-coding RNA exclusively in brain tissue, forming abnormal secondary structures called RNA foci in cerebellar Purkinje cell nuclei 2. These toxic (UGGAA)n-containing transcripts bind to RNA-binding proteins including TDP-43, FUS, and hnRNP A2/B1, with toxicity that is length- and expression level-dependent 3. TDP-43 functions as an RNA chaperone to mitigate this toxicity by resolving abnormal RNA structures 3. SCA31 presents as progressive cerebellar ataxia with Purkinje cell-predominant neurodegeneration 1. The repeat expansions at BEAN1 are occasionally detected in other neurodegenerative contexts, though without clear pathogenic association in Parkinson's disease or ALS cohorts 45. Therapeutic strategies targeting RNA-binding protein function represent promising approaches for SCA31 management 3.