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ALS-FTD Overlap – C9orf72 — SCE Neurology MCQ

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ModerateNeurodegenerative DiseaseALS-FTD Overlap – C9orf72SCE Neurology

A 48-year-old man presents with 6 months of progressive cognitive decline, behavioural change, and personality alteration. He also has fasciculations in both arms and tongue, with progressive limb weakness and brisk reflexes. EMG shows widespread denervation. MRI brain shows bifrontal and anterior temporal atrophy. Genetic testing shows a C9orf72 hexanucleotide repeat expansion. What does this presentation represent?

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Correct answer: C — ALS-FTD overlap syndrome

ALS-FTD overlap is a recognised clinico-pathological entity where patients develop both motor neurone disease (UMN and LMN signs, EMG denervation) and frontotemporal dementia (progressive behavioural/personality change, frontal and temporal atrophy). C9orf72 hexanucleotide repeat expansion is the most common genetic cause of both familial ALS and FTD, and frequently causes ALS-FTD overlap. This overlap occurs in ~15% of ALS patients. A: He has cognitive/behavioural features beyond isolated ALS. B: He has MND features beyond isolated FTD. D: AD causes amnestic dementia without MND. E: CJD is rapidly progressive.

Reference: NICE NG42 MND (2016); EFNS FTD Guidelines; Rascovsky bvFTD Criteria (2011)