SHM Converge Scientific Abstract ePoster Gallery-Amyotrophic Lateral Sclerosis - Frontotemporal Dementia Complex in C9orf72 Mutation

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This case report describes a 33-year-old man with alcohol use disorder who presented with progressive proximal arm weakness, muscle twitching, and later marked muscle atrophy, while initially sparing the lower extremities. Early MRI studies were normal, and an initial EMG showed mild fasciculations and denervation that were mistakenly attributed to alcohol use. He was lost to follow-up for two years, during which his symptoms worsened and he developed severe anxiety, panic attacks, emotional lability, diffuse muscle pain, and elevated creatine kinase.<br /><br />On repeat evaluation, EMG demonstrated diffuse motor neuron dysfunction consistent with amyotrophic lateral sclerosis (ALS). Because of his atypical presentation and psychiatric symptoms, genetic testing was performed and identified a C9ORF72 repeat expansion, along with a LARGE1 mutation. The patient was started on riluzole for ALS, prednisone for suspected myositis, and medications for anxiety and emotional symptoms, with follow-up arranged in an ALS clinic.<br /><br />The report highlights that ALS is often a diagnosis of exclusion and can present with substantial clinical heterogeneity. The C9ORF72 repeat expansion is the most common genetic cause of adult-onset frontotemporal dementia-ALS (FTD-ALS) complex and may also affect early neurodevelopment. Patients with this mutation may develop disease earlier than typical ALS cases and can show psychiatric or frontal-lobe features before clear motor neuron signs appear.<br /><br />Overall, the case emphasizes the importance of considering genetic testing and repeat neurologic assessment in patients with atypical motor weakness, especially when initial findings are inconclusive or confounded by other conditions.

Asset Subtitle

Slake Mokrytzki

Meta Tag

Author List Kunal v. Desai, Maxwell Bressman MD, Nikhita Shrimanker, Slake Mokrytzki

Category Clinical Vignettes

Concept Amyotrophic Lateral Sclerosis

Concept C9ORF72 Repeat Expansion

Concept Diagnosis of Exclusion

Concept Electromyography

Concept Frontotemporal Dementia

Distinguished Non-Finalist

Presenter Organization Greenwich Hospital

Presenting Author Slake Mokrytzki

Track Adult

Keywords

amyotrophic lateral sclerosis

ALS

C9ORF72 repeat expansion

frontotemporal dementia

motor neuron dysfunction

proximal muscle weakness

muscle atrophy

electromyography

genetic testing

alcohol use disorder

Amyotrophic Lateral Sclerosis

C9ORF72 Repeat Expansion

Diagnosis of Exclusion

Electromyography

Frontotemporal Dementia