Other NBIA subtypes include mitochondrial membrane protein-associated neurodegeneration (MPAN, HSP/NBIA-C19orf12, NBIA4, OMIM#614298) and fatty acid hydroxylase-associated neurodegeneration (FAHN, HSP/NBIA-FA2H). The gene discussed is HSP90B2P; the disease is neurodegeneration with brain iron accumulation 4.