<unk>  is any disease or malfunction of the autonomic nervous system.  This includes postural orthostatic tachycardia syndrome (POTS), neurocardiogenic syncope, mitral valve prolapse<unk> , pure autonomic failure, multiple system atrophy (Shy-Drager syndrome),  Autonomic Instability and a number of lesser-known disorders.
In some cases,<unk>  results in a reduction in the ability of the heart and circulatory system to compensate for changes in posture, causing dizziness or syncope (fainting) when one, e.g., stands suddenly. In other cases, the heart may race (tachycardia) for no apparent reason (known as Inappropriate sinus tachycardia), or the kidneys may fail to properly retain water (diabetes insipidus).
The effects of<unk>  may be minor, only limiting the patient's activities slightly, or they may be totally disabling, leaving the patient bedridden.
Dysautonomia
Sleep paralysis
Anorgasmia
Carotidynia
Familial dysautonomia
Presyncope
Myopathy
Erectile dysfunction