Supplementary Material for: Late-Onset Neurodegeneration with Brain Iron Accumulation with Diffusion Tensor Magnetic Resonance Imaging

<b><i>Introduction:</i></b> Neuroferritinopathy is an autosomal dominant neurodegenerative disorder that includes a movement disorder, cognitive decline, and characteristic findings on brain magnetic resonance imaging (MRI) due to abnormal iron deposition. Here, we present a late-onset case, along with diffusion tensor imaging (DTI). <b><i>Case Presentation:</i></b> We report the case of a 74-year-old Caucasian female with no significant past medical history who presented for evaluation of orofacial dyskinesia, suspected to be edentulous dyskinesia given her history of ill-fitting dentures. She had also developed slowly progressive dysarthria, dysphagia, visual hallucinations as well as stereotypic movements of her hands and feet. <b><i>Results:</i></b> The eye-of-the-tiger sign was demonstrated on T2 MRI. Increased fractional anisotropy and T2 hypointensity were observed in the periphery of the globus pallidus, putamen, substantia nigra, and dentate nucleus. T2 hyperintensity was present in the medial dentate nucleus and central globus pallidus. <b><i>Discussion:</i></b> The pallidal MRI findings were more typical of pantothenate kinase-associated neurodegeneration (PKAN), but given additional dentate and putamenal involvement, lack of retinopathy, and advanced age of onset, PKAN was less likely. Although the patient’s ferritin levels were within low normal range, her clinical and imaging features led to a diagnosis of neuroferritinopathy. <b><i>Conclusion:</i></b> Neurodegeneration with brain iron accumulation (NBIA) is a rare cause of orofacial dyskinesia. DTI MRI can confirm abnormal iron deposition. The location of abnormal iron deposits helps in differentiating NBIA subtypes. Degeneration of the dentate and globus pallidus may occur via an analogous process given their similar T2 and DTI MRI appearance.

<b><i>引言：</i></b> 神经铁蛋白病（Neuroferritinopathy）是一种常染色体显性神经退行性疾病，表现为运动障碍、认知功能减退，以及因铁异常沉积导致的脑磁共振成像（magnetic resonance imaging，MRI）特征性改变。本文报告1例晚发型病例，并附带弥散张量成像（diffusion tensor imaging，DTI）资料。
<b><i>病例介绍：</i></b> 本次报告1例74岁白人女性病例，既往无显著病史，因口面运动障碍就诊，结合其义齿适配不良病史，怀疑为无牙颌运动障碍（edentulous dyskinesia）。患者还出现了缓慢进展的构音障碍、吞咽困难、视幻觉以及手足刻板运动。
<b><i>结果：</i></b> T2加权MRI可见虎眼征（eye-of-the-tiger sign）。在苍白球、壳核、黑质及齿状核的外周区域，可见各向异性分数（fractional anisotropy，FA）升高及T2低信号。齿状核内侧及苍白球中央区域可见T2高信号。
<b><i>讨论：</i></b> 苍白球的MRI表现更符合泛酸激酶相关神经变性（pantothenate kinase-associated neurodegeneration，PKAN），但考虑到同时存在齿状核与壳核受累、无视网膜病变，且发病年龄较晚，PKAN的可能性较低。尽管患者的铁蛋白水平处于正常低限，但结合其临床及影像学特征，最终诊断为神经铁蛋白病（Neuroferritinopathy）。
<b><i>结论：</i></b> 脑铁积聚性神经退行性疾病（Neurodegeneration with brain iron accumulation，NBIA）是引发口面运动障碍的罕见病因。弥散张量成像（DTI）可证实铁异常沉积。异常铁沉积的部位有助于区分NBIA的不同亚型。鉴于齿状核与苍白球在T2及DTI影像学上的表现相似，二者的变性过程可能具有相似性。