(Likely) pathogenic variants resulted in 3 groups based on disease association: ALS-FTD (C9orf72, TBK1), pure HSP (SPAST, SPG7), "ALS-HSP-CMT overlap" (FIG4, NEFL, SPG11).<h4>Discussion</h4>In a cohort of 139 PLS patients, genetic analyses resulted in 31 variants (22%) of which 10 (7%) (likely) pathogenic associated with different diseases (predominantly ALS and HSP). This evidence concerns the gene C9orf72 and frontotemporal dementia.