PLA2G6 and neurodegeneration with brain iron accumulation: NBIA now includes (a) PKAN (also called NBIA1) caused by mutations in the PANK2 gene, (b) PLA2G6-associated neurodegeneration (PLAN, NBIA2) due to phospholipase A2 mutations, (c) neuroferritinopathy due to mutations in the ferritin light chain (FTL) gene, (d) aceruloplasminemia due to a mutation in the ceruloplasmin gene, and (e) sporadic cases of NBIA in which the genetic background has not been identified.