We describe a case of Huntington’s disease (HD) associated chorea and concurrent functional movement disorder (FMD).

HD is a neurodegenerative disorder characterized by a triad of motor, neuropsychiatric and cognitive manifestations, which have complex interactions with each other. FMD are a phenomenologically heterogeneous group of movement disorders that are incongruent with patterns of organic disease. Patients with HD have multiple psychosocial stressors and while rare, FMD can be one of the motor manifestations of HD.

Video-based case report.

A 35-year-old woman with a family history of HD presented with a one-year of depressed mood and involuntary movements. Physical exam was pertinent for choreiform movements in her upper extremities; remainder of the exam (including gait) was unremarkable. Genetic testing revealed 48 CAG repeats.  Three months later, she presented with worsening depression, abnormal gait and daily falls. Repeat examination revealed abnormal astasia-abasia gait and excessive slowness of movements, which was distractible. While her prior choreiform movements were congruent with HD, the phenomologic features of her gait findings led to a concurrent diagnosis of FMD. We initiated treatment with venlafaxine and risperidone to address her underlying neuropsychiatric symptoms of anxiety and depression. She was also encouraged to incorporate non-pharmacologic aids such as counseling, physical exercise and meditation to alleviate her psychosocial stressors.  Over the course of six months, she endorsed an improvement in mood as well as her motor symptoms with persistence of minimal appendicular chorea and resolution of the astasia-abasia on exam.  

To our knowledge, this is the first described case of astasia-abasia gait as a FMD presentation in a patient with HD. It reflects the complex interaction between neuropsychiatric and motor symptoms in HD and highlights the importance of treating all the different manifestations of the disease. Early diagnosis and treatment of FMD can positively influence the patient’s quality of life.