Mutations in the human patatin-like lysophospholipase domain containing the 6 gene PNPLA6 encode an evolutionarily conserved (lyso)phospholipase, leading to the development of a complex hereditary spastic paraplegia 39 (SPG 39) and a number of rare severe syndromes in humans. Here, PNPLA6 is linked to hereditary spastic paraplegia 39.