At least 15 diseases have been identified in this group, including the four most common forms, which are pantothenate kinase-associated neurodegeneration (PKAN), phospholipase A2 group VI (PLA2G6)-associated neurodegeneration (PLAN), beta-propeller protein-associated neurodegeneration (BPAN) and mitochondrial membrane protein-associated neurodegeneration (MPAN) [87]. This evidence concerns the gene PLA2G6 and neurodegeneration with brain iron accumulation 5.