Autonomic nervous system disorder due to certain specified neurodegenerative disorder

**Definition:** Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterised by varied combinations of parkinsonian, cerebellar, autonomic (erectile dysfunction, bladder dysfunction, orthostatic hypotension) and pyramidal features. The disease belongs to the group of alpha-synucleinopathies, a group of diseases characterised by aggregation of alpha-synuclein in affected brain regions. There are two different types: MSA-P (with parkinsonism) and MSA-C (with cerebellar dysfunction).