These are:
Parkinsonism - slow, stiff movement, writing becomes small and spidery
Cerebellar dysfunction - difficulty coordinating movement and balance
Autonomic nervous system dysfunction - impaired automatic body functions, including one, some, or all of the following:postural or orthostatic hypotension, resulting in dizziness or fainting upon standing up
urinary incontinence or urinary retention
impotence
constipation
vocal cord paralysis
dry mouth and skin
trouble regulating body temperature due to sweating deficiency in all parts of the body
loud snoring, abnormal breathing or inspiratory stridor during sleep
other sleep disorders including sleep apnea, REM behavior disorder
double vision
muscle twitches
Cognitive impairment

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.A follow-up study was unable to replicate this finding in American MSA patients. The authors of the U.S. 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. "Another study investigated the frequency of RFC1 intronic repeat expansions, a phenomenon implicated in CANVAS; a disease with a diagnostic overlap with MSA.
Apnea (BrE: apnoea) is the temporal cessation of breathing. During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. Depending on how blocked the airways are (patency), there may or may not be a flow of gas between the lungs and the environment, but if theres sufficient flow, gas exchange within the lungs and cellular respiration wouldnt be severely affected. Voluntarily doing this is called holding ones breath. Apnea may first be diagnosed in childhood, and it is recommended to consult an ENT specialist, allergist or sleep physician to discuss symptoms when noticed; malformation and/or malfunctioning of the upper airways may be observed by an orthodontist. Cause
Apnea can be involuntary—for example, drug-induced (such as by opiate toxicity), mechanically / physiologically induced (for example, by strangulation or choking), or a consequence of neurological disease or trauma. During sleep, people with severe sleep apnea can have over thirty episodes of intermittent apnea per hour every night.Apnea can also be observed during periods of heightened emotion, such as during crying or accompanied by the Valsalva maneuver when a person laughs. Apnea is a common feature of sobbing while crying, characterised by slow but deep and erratic breathing followed by brief periods of breath holding when crying. Another example of apnea are breath-holding spells; these are sometimes emotional in cause and are usually observed in children as a result of frustration, emotional stress and other psychological extremes.