DBHD or Dopamine Beta-Hydroxylase Deficiency, is a very rare condition that has only been diagnosed in 20 people. It affects the autonomic nervous system, which controls involuntary body functions like the regulation of blood pressure and body temperature.
Symptoms include:
- Sharp drop in blood pressure causing dizziness, blurred vision, or fainting when standing up
- Extreme fatigue during exercise
- Droopy eyelids
- Nasal congestion
- Inability to stand for a long time
Some links for more info:
U.S. National Library of Medicine
BioMed Central