Editing Multiple system atrophy (section)

==Genetics==
One study found a correlation between the deletion of genes in a specific genetic region and the development of MSA in a group of Japanese patients. The region in question includes the [[SHC2]] gene which, in mice and rats, appears to have some function in the nervous system. The authors of this study hypothesized that there may be a link between the deletion of the SHC2 and the development of MSA.<ref name=Sasaki2011>{{cite journal | vauthors = Sasaki H, Emi M, Iijima H, Ito N, Sato H, Yabe I, Kato T, Utsumi J, Matsubara K | display-authors = 6 | title = Copy number loss of (src homology 2 domain containing)-transforming protein 2 (SHC2) gene: discordant loss in monozygotic twins and frequent loss in patients with multiple system atrophy | journal = Molecular Brain | volume = 4 | pages = 24 | date = June 2011 | pmid = 21658278 | pmc = 3141657 | doi = 10.1186/1756-6606-4-24 | quote = Copy number loss of SHC2 strongly indicates a causal link to MSA. | doi-access = free }}</ref>

A follow-up study was unable to replicate this finding in American MSA patients.<ref name="pmid24170347">{{cite journal | vauthors = Ferguson MC, Garland EM, Hedges L, Womack-Nunley B, Hamid R, Phillips JA, Shibao CA, Raj SR, Biaggioni I, Robertson D | display-authors = 6 | title = SHC2 gene copy number in multiple system atrophy (MSA) | journal = Clinical Autonomic Research | volume = 24 | issue = 1 | pages = 25–30 | date = February 2014 | pmid = 24170347 | pmc = 3946192 | doi = 10.1007/s10286-013-0216-8 }}</ref> The authors of the study concluded that "Our results indicate that SHC2 gene deletions underlie few, if any, cases of well-characterized MSA in the US population. This is in contrast to the Japanese experience reported by Sasaki et al., likely reflecting heterogeneity of the disease in different genetic backgrounds."{{clarify|date=July 2021}}

Another study investigated the frequency of [[RFC1]] intronic repeat expansions, a phenomenon implicated in [[Cerebellar ataxia|CANVAS]]; a disease with a diagnostic overlap with MSA.<ref name=":1">{{cite journal | vauthors = Sullivan R, Yau WY, Chelban V, Rossi S, O'Connor E, Wood NW, Cortese A, Houlden H | display-authors = 6 | title = RFC1 Intronic Repeat Expansions Absent in Pathologically Confirmed Multiple Systems Atrophy | journal = Movement Disorders | volume = 35 | issue = 7 | pages = 1277–1279 | date = July 2020 | pmid = 32333430 | doi = 10.1002/mds.28074 | s2cid = 216129457 }}</ref><ref>{{cite journal | vauthors = Cortese A, Simone R, Sullivan R, Vandrovcova J, Tariq H, Yau WY, Humphrey J, Jaunmuktane Z, Sivakumar P, Polke J, Ilyas M, Tribollet E, Tomaselli PJ, Devigili G, Callegari I, Versino M, Salpietro V, Efthymiou S, Kaski D, Wood NW, Andrade NS, Buglo E, Rebelo A, Rossor AM, Bronstein A, Fratta P, Marques WJ, Züchner S, Reilly MM, Houlden H | display-authors = 6 | title = Biallelic expansion of an intronic repeat in RFC1 is a common cause of late-onset ataxia | journal = Nature Genetics | volume = 51 | issue = 4 | pages = 649–658 | date = April 2019 | pmid = 30926972 | pmc = 6709527 | doi = 10.1038/s41588-019-0372-4 }}</ref> The study concluded that these repeats were absent in pathologically confirmed MSA, suggesting an alternative genetic cause.<ref name=":1" />