FA2H and fatty acid hydroxylase-associated neurodegeneration: Fatty acid hydroxylase-associated neurodegeneration (FAHN) (with fatty acid 2 hydroxylase (FA2H) mutation), neuroferritinopathy (with Ferritin (FTL1) mutation), aceruloplasminemia (with ceruloplasmin (CP) mutation), Woodhouse–Sakati syndrome (with DB1 and Cul4-associated factor 17 mutation), Kufor–Rakeb syndrome (with ATPase cation transporting 13A2 mutation), and COASY protein-associated neurodegeneration (with CoA synthase mutation) are rare diseases affecting less than 1% of NBIA cases (Table 1) [28].