A 14-year-old boy presented with frequent falls over the past 2 years. These were accompanied by declining gross and fine motor skills with overall clumsiness and changes in hand shape. He had difficulties with handwriting, grasping objects, and dressing.

Prior medical history included development of tics at 10 years old, which improved with age. Family history included a mother with thrombophilia and maternal uncle with intellectual disability.

Physical examination revealed intermittent ulnar deviation of fingers and toes and scoliosis with winged scapulae. Gait was normal with appropriate arm swinging, but some instability was observed during transitions. Motor and sensory exams were normal with preserved reflexes.

Ophthalmologic evaluation with slit lamp was normal.

EMG/NCS demonstrated mild neuropathy of median nerves.

Brain MRI showed abnormal mineralization and gliosis of the globi pallidi interna ( Fig. 72.1 ).

Pantothenate kinase-associated neurodegeneration (PKAN). Brain MRI, (A) axial T2, (B) GRE, (C) FLAIR, and (D) coronal T2 show globus pallidus peripheral and central hypointensity due to iron deposition, with intervening layer of hyperintensity reflective of gliosis. FLAIR , Fluid-attenuated inversion recovery.

Genetic panel revealed a pathogenic variant in the PANK2 gene.

Dystonia can be primary or secondary. Primary dystonias are thought to be genetic or idiopathic.

Heredodegenerative disorders should be considered when abnormal movements, psychiatric disorders, and changes in motor skills are present.

Metabolic diseases with progressive neurological symptoms include mitochondrial disease, Wilson disease, Leigh disease, and coenzyme Q10 deficiency.

Secondary dystonias result from extrinsic factors causing basal ganglia injury such as drugs/toxins, trauma, infection, inflammation, or ischemia.

Neurodegeneration with brain iron accumulation (NBIA) involves excessive iron deposition in the brain. The pattern of distribution distinguishes the various subtypes of NBIA.

Pantothenate kinase-associated neurodegeneration (PKAN) selectively involves the globi pallidi. The “eye-of-the-tiger” sign is diagnostic, with peripheral and central susceptibility and intervening T2-hyperintense gliosis.

Woodhouse-Sakati syndrome can variably show prominent susceptibility in the globi pallidi without “eye-of-the-tiger” sign. Marked periventricular T2 white matter hyperintensity is present.

Fatty acid hydroxylase-associated neurodegeneration shows susceptibility in the globi pallidi and substantia nigra, with white matter T2 hyperintensity and atrophy of corpus callosum, cerebellum, and brainstem.

Neuroferritinopathy shows mixed T2 signal in the deep gray nuclei, progressing to susceptibility and cavitation.

PLA2G6 -associated neurodegeneration shows cerebellar atrophy with variable susceptibility in the globus pallidus and substantia nigra.

Kufor-Rakeb syndrome shows susceptibility in the deep gray nuclei and diffuse cerebral, cerebellar, and brainstem atrophy, particularly corticospinal tracts.

Aceruloplasminemia shows widespread susceptibility throughout the deep gray nuclei and cortex, diffuse white matter hyperintensity, and cerebellar atrophy.

Beta-propeller protein-associated neurodegeneration shows T1 hyperintensity in the substantia nigra with a central hypointense band.

Basal ganglia susceptibility can be seen with deposition of other biometals, such as calcium, copper, and manganese, as well as gadolinium MRI contrast deposition. Findings will diffusely affect the deep gray nuclei and may show corresponding intrinsic T1 shortening.

Acquired brain injury (neuroinflammation, vascular disorders, radiation) can be associated with premature iron deposition in the basal ganglia. These conditions will show additional imaging findings, with secondary degeneration of the deep gray nuclei.