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Comment & Response
January 2019

Neuropathology of Circadian Alterations in Parkinson Disease

Author Affiliations
  • 1International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
JAMA Neurol. 2019;76(1):115. doi:10.1001/jamaneurol.2018.3755

To the Editor In a recent study published in JAMA Neurology, De Pablo-Fernàndez et al1 reported what is, to our knowledge, the first detailed histological study that examined the neuropathological status of the suprachiasmatic nucleus (SCN) and pineal gland in 3 neurological conditions: Parkinson disease (PD), multiple system atrophy, and progressive supranuclear palsy. This letter will focus on PD. De Pablo-Fernàndez et al1 stained 8-μm thick sections that were prepared from postmortem formalin-fixed hypothalamic and pineal tissue for α-synuclein.1 This protein is used as a marker for Lewy bodies and neurites that are hallmark neuropathological features for PD.2 The authors found Lewy depositions in 9 of 13 SCN cases (69.2%) and in only 2 of 17 pineal gland samples (11.8%). Using a semiquantitative scoring system with a 5-level expression intensity scale (absent, mild, moderate, severe, or very severe), the intensity of the staining in the SCN was evaluated as mild to moderate. In the pineal gland, only mild α-synuclein depositions in the form of Lewy neurites were found in 2 patients with PD.1

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