Neuropathology of α-synucleinopathy

Shigeo Murayama, Yuko Saito

Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology

Alpha-synucleinopathy (AS) comprises Lewy body (LB) disease (LBD) including Lewy body-type Parkinson disease, dementia with Lewy bodies and Lewy body-type pure autonomic failure as well as multiple system atrophy (MSA) with glial and neuronal cytoplasmic and nuclear inclusions.　Neuropathology of LBD is defined by the presence of LB.　Since LBs are present around 25% of all the cases of the Brain Bank for Aging Research (BBAR), that roughly represent a general aging cohort with the average of 80 years of age, LB-related AS is now regarded as one of the common accumulation of abnormally processed proteins, that becomes symptomatic over a certain threshold level.　AS is harmful to the cells and the formation of LBs are supposed to be beneficial to sequestrate the life-threatening protein.　In contrast, the incidence of MSA is 1 in 100,000 level and only one case of probable asymptomatic early stage of MSA is detected in the recent 1,680 serial autopsy cases from the BBAR.　MSA-type AS is, thus, more pathogenetic and nuclear AS is unique in this type.　Families with both MSA and LBD cases as well as several case reports complicated by both MSA and LBD indicate common process in these two types of AS.

Address correspondence to Dr. Shigeo Murayama, Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology (35-2, Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan)