Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by autonomic failure with various combinations of parkinsonism, cerebellar ataxia, and pyramidal dysfunction. The prevalence of MSA has been estimated to be 9.3 per 100,000, based on the national registry in Japan (Japan Intractable Diseases Information Center, https://www.nanbyou.or.jp/) with a mean age at onset in the late fifties. MSA is a progressive disease with median intervals from onset to confinement to a wheelchair and death are 5 and 9 years, respectively.

Glial cytoplasmic inclusions (GCIs), composed of misfolded α-synuclein, have been discovered as the neuropathological hallmark, and it has been proposed that misfolded α-synuclein may spread in a prion-like manner to neighboring cells and functionally connected brain regions. The etiologies underlying the formation of GCIs, however, remain to be elucidated. To establish efficacious disease-modifying therapy for MSA, elucidation of etiologies of MSA is the urgent target in MSA research.

With these backgrounds, the International Congress of Multiple System Atrophy focusing solely on MSA has been held to promote researches in MSA and communication among scientists working in this field. Given the worldwide outbreak of COVID-19, the 7th International Congress of Multiple System Atrophy was organized by Shoji Tsuji (Tokyo) and held as an online meeting on February 26–27, 2021. The Program focused on the broad research fields covering the basic biology of α-synucleinopathy, development of biomarkers, molecular genetics, clinical aspects, and development of disease-modifying therapies. As invited speakers, Ronald Melki (Paris), Horacio Kaufmann (New York), Iva Stankovic (Belgrade), Gregor K. Wenning (Innsbruck), Maria Teresa Pellecchia (Salerno), Werner Poewe (Innsbruck), Klaus Seppi (Innsbruck), Wolfgang Singer (Rochester), Vik Khurana (Boston) participated in the Congress. Cynthia Roemer and Pam Bower from MSA Coalition Board of Directors also participated in the Congress.

The special issue MSA was organized to feature the latest research accomplishments including those presented in the 7th International Congress of Multiple System Atrophy. As described in the manuscripts in this special issue, we are witnessing remarkable progress in the MSA research, and we wish the MSA research will further progress to realize efficacious disease-modifying therapy for MSA.