A Schizophrenia‐Spectrum Presentation with Panda Sign: Huntington's Disease Confirmed, Wilson Disease Excluded

A 46-year-old man presented with progressive self-neglect, social withdrawal, cognitive decline, chronic suicidality, and a schizophrenia-spectrum phenotype since early adulthood. Examination showed formal thought disorder, blunted affect, choreiform hand, arm, leg and torso movements (Video 1), brisk reflexes, broad-based gait, and impaired tandem walking. Neuropsychology demonstrated deficits in attention, working memory, visuospatial ability, and executive control. Brain MRI revealed a mesencephalic T2-FLAIR hyperintensity surrounding the red nuclei and substantia nigra, producing the classic “face of the giant panda” sign [1], together with caudate head atrophy, frontal horn enlargement, Sylvian fissure widening, and cortical atrophy (Fig. 1). Low ceruloplasmin and serum copper initially suggested Wilson's disease (WD), but these changes also occur in protein deficiency states, including malnutrition, and other protein-losing conditions. Kayser-Fleischer rings were absent, liver ultrasound was normal, ATP7B testing was negative. HTT analysis confirmed Huntington's disease (HD) with a heterozygous expanded CAG repeat (43 ± 2)[2]. This case shows that the panda sign is not pathognomonic of WD and may occur in genetically confirmed HD. When prominent psychiatric symptoms coexist with hyperkinesia, cognitive impairment, and mixed radiological or biochemical findings, diagnosis should not rely on a single imaging sign. Genetic testing was decisive in distinguishing HD from WD and guiding treatment. This study did not require approval by the Scientific Board of the AHEPA General University Hospital of Thessaloniki, Greece. We report according to the Declaration of Helsinki principles which set internationally recognized ethical standards for medical research involving human participants. Informed patient consent was verbally obtained and documented in the patient's electronic hospital record and in writing in the patient's hand-written hospital records. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines. Optional multiple-choice question: Which diagnosis was genetically confirmed in this patient? A. Wilson's disease. B. Huntington's disease. C. Neurodegeneration with brain iron accumulation. D. Fahr disease. Correct answer: B. Huntington's disease. Explanation: Although the “face of the giant panda” sign and low copper studies initially suggested Wilson's disease, ATP7B testing was negative and HTT analysis confirmed Huntington's disease. 1. Research Project: A. Conception, B. Organization, C. Execution; 2. Manuscript Preparation: A. Writing of the First Draft, B. Review and Critique. E.M.T.: 1A, 1B, 1C, 2A, 2B. G.Z.: 1A, 2A, 2B. E.P.: 1C, 2A, 2B. A.G.: 1C. A.K.: 1A, 1C, 2A, 2B. K.N.F.: 1A, 2B. The publication of this article in OA mode was financially supported by HEAL-Link. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.