Abstract
Neurodegeneration with brain iron accumulation (NBIA) refers to a group of rare genetic disorders characterized by abnormal iron deposition in the basal ganglia and brainstem due to impaired iron homeostasis. Disease severity and manifestations vary according to the underlying genetic mutation and age of presentation; however, most subtypes share progressive neurological features such as dystonia, Parkinsonism, spasticity, cognitive decline, and intellectual disability. In this review, we first outline the physiological role of iron in the central nervous system, emphasizing its importance for neurotransmitter synthesis, myelination, and mitochondrial metabolism, and discuss how disruption of homeostatic mechanisms may lead to ferroptosis and neuronal injury. We then explore the role of neuroimaging in the diagnosis of NBIA, with a focus on MRI as the modality of choice. Finally, we provide an overview of the clinical and imaging features of the major NBIA subtypes, highlighting both shared characteristics and distinctive patterns. Covered NBIA include primary disorders of iron metabolism, such as neuroferritinopathy and aceruloplasminemia, and secondary disorders with disrupted iron regulation, including Pantothenate Kinase-Associated Neurodegeneration, Phospholipase A2 Group VI-Associated Neurodegeneration, Mitochondrial Membrane Protein-Associated Neurodegeneration, Beta-Propeller Protein-Associated Neurodegeneration, Fatty Acid Hydroxylase-Associated Neurodegeneration, Coenzyme A Synthetase Protein-Associated Neurodegeneration, Woodhouse-Sakati syndrome, and Kufor-Rakeb Disease. By integrating genetics, pathophysiology, and imaging, this review aims to improve recognition of NBIA and support comprehensive clinical management.