Dream Enactment Behavior Disorder Associated with Pallido‐Nigro‐Luysian Degeneration and Tau Proteinopathy

Background Pallido-nigro-luysian atrophy (PNLA) is a rare neurodegenerative disorder with only a few cases reported to date. Although the clinical picture usually resembles progressive supranuclear palsy, pathological examination reveals more selective atrophy and loss of neurons in the globus pallidus, substantia nigra and subthalamic nucleus. Objectives To describe the clinical features and pathological findings of a patient with PNLA. Methods Case report with clinico-pathological discussion. Results An 83-year-old man presented to our clinic with a vertical supranuclear gaze palsy, parkinsonism, gait impairment and sleep abnormalities suggestive of REM-sleep behavior disorder. Neuropathological examination 5 years after symptom onset revealed subcortical tau proteinopathy compatible with a PNLA pattern. There was also an associated mild degree of limbic/subcortical inflammatory response, Alzheimer's disease-related changes, as well as argyrophilic grain disease. Conclusions We present a comprehensive clinico-pathological discussion of a patient with PNLA. Besides parkinsonism and vertical supranuclear gaze palsy, the patient also had a sleep disorder, clinically suggestive of REM behavioral disorder, which has not been previously reported in PNLA. We expand the clinical phenotype of this rare condition and provide neuropathological evidence for the associated abnormalities.