PNPLA6 and hereditary spastic paraplegia: Additionally, mutations in another core metabolic component of the PE/PC cascade, PNPLA6 (also known as NTE; neuropathy target esterase), which catalyses the conversion of PC to lysophosphatidylcholine (LPC) and LPC to glycerophosphocholine (GPC), have been associated with a range of HSP presentations, as well as other more complex neurological and retinal disorders (Synofzik et al., 2013; Topaloglu et al., 2014; Hermansson et al., 2016).