Characteristic MRI findings in beta-propeller protein-associated neurodegeneration (BPAN)

A 31-year-old woman presented with severe dystonia-parkinsonism. She had nonprogressive psychomotor retardation and cognitive dysfunction from childhood without evidence of dystonia or parkinsonism. At age 30, she then developed severe dystonia and gait disturbance. There was neither dystonia nor parkinsonism before age 30. MRI revealed cerebral atrophy and iron accumulation in the globus pallidus and substantia nigra (figure 1, A–D). The characteristic MRI findings were hyperintensity of the substantia nigra with a central band of hypointensity in T1-weighted axial slices (figure 1, B). Beta-propeller protein-associated neurodegeneration (BPAN) was diagnosed based on MRI findings and identification of a novel heterozygous mutation in the WDR45 gene (NM_007075.3: c.519+1_519+3del) (figure 2). This is a neurodegeneration involving brain iron accumulation (NBIA) characterized by psychomotor retardation from childhood and dystonia-parkinsonism in midadulthood.^1,2 Although we could not analyze the father's gene since he had died, the mother had no mutation in the WDR45 gene (figure 2). Thus, it might be a de novo mutation in the WDR45 gene, as reported previously.^1,2