DDHD1 and hereditary spastic paraplegia: Mutations in the phospholipase A1 family members DDHD1 (Bouslam et al., 2005; Tesson et al., 2012; Liguori et al., 2014) and DDHD2 (Schuurs-Hoeijmakers et al., 2012; Gonzalez et al., 2013; Citterio et al., 2014; Doi et al., 2014; Magariello et al., 2014) have recently been linked to autosomal-recessive forms of hereditary spastic paraplegia (HSP).