PNPLA6 and aceruloplasminemia: Mutations in the NTE/PNPLA6 (neuropathy target esterase/patatin-like phospholipase domain containing 6) gene are responsible not only for autosomal recessive HSP (SPG39) [6], but also for other rare neurological syndromes: ataxia with spasticity or pure cerebellar ataxia [7,8,9], Gordon Holmes syndrome, Boucher–Neuhäuser syndrome, Laurence–Moon syndrome, Oliver–McFarlane syndrome and Leber congenital amaurosis [10,11,12,13,14]; also see [15] for review.