By adding this additional diagnosis through RFC1 repeat expansion to the previous data, we obtained a total positive genetic diagnosis in 86 out of 135 HSP/ataxia cases (64%), which increased to 95 (70%) when considering the phenotypically compatible VUS variants (Fig. 4B and 4C; Additional file 1: Tables S2 and S5, and “ Methods”). This evidence concerns the gene RFC1 and Ataxia.