Of further relevance, HSP has also been linked to mutations of the calcium-independent phospholipase A2 beta (PLA2G6) (58, 59), a key enzyme influencing phospholipid metabolism, which acts by hydrolyzing fatty acyl groups at the sn-2 position, yielding lysophospholipids and free fatty acids (60, 61). Here, PLA2G6 is linked to hereditary spastic paraplegia.