An update on multiple system atrophy.

PURPOSE OF REVIEW: Multiple system atrophy (MSA) is a rapidly progressive synucleinopathy characterized by autonomic failure, parkinsonism, and cerebellar ataxia. Here, we provide an update on α-synuclein's role in MSA pathophysiology and review the new Movement Disorders Society (MDS) diagnostic criteria and the utility of α-synuclein-based biomarkers. We also highlight ongoing efforts toward clinical trial readiness and review potential disease-modifying therapies undergoing clinical trials.

RECENT FINDINGS: A role of urinary tract infections in triggering α-synuclein aggregation and contribution of genes implicated in oligodendroglial development have been suggested in the MSA pathophysiology. The clinically probable MSA category of the new diagnostic criteria shows improved accuracy in early disease stages. Predictors of phenoconversion from pure autonomic failure to MSA are now better defined. Alpha-synuclein strains in CSF and serum, phosphorylated α-synuclein deposits in the skin, and brain α-synuclein pathology visualized using PET ligand [18F]ACI-12589 are emerging as valuable diagnostic tools. Clinical trials in MSA investigate drugs targeting α-synuclein aggregation or preventing α-synuclein expression, along with stem cell and gene therapies to halt disease progression.

SUMMARY: New MSA diagnostic criteria and α-synuclein-based biomarkers may enhance diagnostic accuracy while promising therapies are in development to address disease progression.