BEAN1 and spinocerebellar ataxia type 31: Among the repeat expansion-related diseases, spinocerebellar Ataxia type 31 (SCA31) is caused by the repeat expansion of 2.5 to 3.8 kbp pentanucleotide TGGAA, where a pure (TGGAA)n extended for at least 110 repeats in the intron region of the BEAN gene (Sato et al., 2009), whereas benign adult familial myoclonic epilepsy (BAFME1) is associated with the repeat expansion of 105 to 3,680 units of TTTCA (Cen et al., 2018; Ishiura et al., 2018).