Abstract
Introduction We report a case of patient presenting with clinical features suggestive of progressive supranuclear palsy (PSP) as well as primary lateral sclerosis (PLS).
Case A 66-year-old left-handed man presented with a 5-year history of progressive gait disorder on a background of a previous ischaemic stroke, punctuated by a more recent 8-month history of functional decline becoming wheelchair bound and with the development of dysarthria and dysphagia. His past medical history included type 2 diabetes mellitus, ischaemic heart disease, hypertension, and prior ischaemic stroke. His father had Parkinson’s disease, one first cousin had amyotrophic lateral sclerosis, and another first cousin with primary lateral sclerosis. All were deceased at the time of assessment of the patient.
Neurological examination demonstrated hypomimia, bradykinesia, hypophonia, dysarthria, left upper limb cogwheel rigidity with coactivation, hyperreflexia in the upper and lower limbs, reduced distal power bilaterally in the lower limbs, square wave jerks, saccadic pursuits with restricted upward gaze and a positive palmomental reflex, applause sign and glabella tap.
MRI brain demonstrated no specific neurodegenerative pattern. Electrophysiology studies were consistent only with diabetic neuropathy with no active denervation. Lumbar puncture however, was significant for Abeta1–42 and P-Tau 181.
Genetic testing was undertaken and identified a pathogenic variant in TBK1 that is associated with autosomal dominant frontotemporal dementia and/or amyotrophic lateral sclerosis but increasingly recognised in also causing atypical Parkinsonism.
Conclusion This unusual presentation highlights the phenotypical overlap of pyramidal and extrapyramidal disorders, further emphasising the vast clinical and genetic heterogeneity in neurodegenerative conditions.
