FA2H and fatty acid hydroxylase-associated neurodegeneration: Mutations in the FA2H gene that reduce or abolish activity of the enzyme cause a complicated form of hereditary spastic paraplegia type 35 (SPG35) associated with leukodystrophy, which is also known as fatty acid hydroxylase-associated neurodegeneration (FAHN) and as a subtype of neurodegeneration with brain iron accumulation (NBIA) [13].