Objective: To present a case of juvenile-onset Huntington’s disease (HD) with a mixed phenotype and abnormal brain imaging.

Background: HD is an autosomal-dominant neurodegenerative disorder associated with the expansion of unstable CAG trinucleotide repeats in the huntingtin gene (HTT) on chromosome 4 [1]. It is characterized by progressive behavioral changes, cognitive dysfunction, and motor disturbances which classically include chorea. However, 5-10% of HD cases present with the Westphal variant of HD, a distinct clinical syndrome characterized by hypokinetic symptoms (rigidity and bradykinesia), myoclonus, cerebellar signs, and/or seizures [1-2].

Method: We present a brief case report of a young girl seen in the Movement Disorders Clinic at the University of Alabama at Birmingham.

Results: A 17-year-old girl presents from a psychiatric care facility with a one-year history of imbalance and falls. Care staff have also reported slurred speech, a softening of her voice, and a blank facial expression. She was not raised by her parents and cannot provide a family or developmental history. On exam, she exhibits hypomimia, slowed vertical and horizontal saccadic eye movements, mild bilateral rigidity and bradykinesia, motor impersistence on tongue protrusion, and rare chorea of her hands and feet. Magnetic resonance (MR) imaging of the brain shows symmetric, bilateral T2-FLAIR hyperintensities in the caudate and putamen as well as caudate atrophy [figure1]. Genetic testing reveals an abnormal CAG repeat expansion within the HTT gene with allelic repeat numbers 62 and 22.

Conclusion: MR imaging in adult-onset HD classically shows hypointense signal in the caudate nucleus and putamen on T2-FLAIR. However, the Westphal variant of HD is more commonly associated with hyperintensities in these regions [3]. This young patient presented with a mixed phenotype of mild chorea and parkinsonism, but with MR imaging findings classically seen with the Westphal variant of HD. In children presenting with a combination of hypokinetic and hyperkinetic movements, MR imaging may be helpful in assisting with the diagnosis of HD and distinguish it from other conditions with similar presentations, such as: spinocerebellar ataxia, Friedreich ataxia, and the metal accumulation disorders [4].

References: [1] Walker, F.O. Huntington’s disease. Lancet. 2007; 369(9557): 218-28. [2] Quigley, J. Juvenile Huntington’s Disease: Diagnostic and Treatment Considerations for the Psychiatrist. Curr Psychiatry Rep. 2017; 19: 9. [3] Ho, V.B, Chuang, H.S., and Koo, B. Juvenile Huntington disease: CT and MR features. AJNR Am J Neuroradiol. 1995; 16(7): 1405-12. [4] Martino, D., Stamelou, M., and Bhatia, K.P. The differential diagnosis of Huntington’s disease-like syndromes: ‘red flags’ for the clinician. J Neurol Neurosurg Psychiatry. 2013; 84(6): 650-6.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/involuntary-movements-with-abnormal-brain-imaging-a-case-report/