B4GALNT1 and hereditary spastic paraplegia: In total, 13 pathogenic variants of B4GALNT1, including a splicing mutation, 7 missense mutations and 5 inserts/deletions mutations, have already been reported in 14 SPG26‐related HSP families with variable complicated phenotypes (Boukhris et al., 2013; Dad et al., 2017; Harlalka et al., 2013; Rose et al., 2020; Wakil et al., 2014).