Mutations in another HSP molecule, spartin (SPG20), are associated with an autosomal recessive complex form of HSP originally identified in the Amish community and subsequently described elsewhere, encompassing neurological as well as non-neurological features (Patel, 2002; Ciccarelli et al., 2003; Bizzari et al., 2017; Dardour et al., 2017). This evidence concerns the gene SPART and hereditary spastic paraplegia.