HSP subtypes which more commonly cause a ‘spastic ataxia’ phenotype are the recessive forms SPG7 and SPG15 (and the very rare subtypes due to SPG30 and SPAX mutations); these conditions enter the differential diagnosis with Friedreich ataxia and related diseases, autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), and spinocerebellar ataxia (SCA) subtypes with spasticity (i.e., SCA1, 3, 7, 10, 11, 12) [9]. Here, KIF1A is linked to Autosomal recessive spastic ataxia of Charlevoix-Saguenay.