New research sheds light on the role of genetics in POTS:
the norepinephrine transporter gene ( this gene has been implicated in POTS in one family in the U.S., but despite testing thousands of other patients, the same mutation was not found in other POTS patients.
Recently, researchers in Australia decided to look at the amount of norepineprhine transporter (NET) in POTS patients, and found that, even though the SLC6A2 gene mutation was not present, POTS patients tended to have a deficit of NET compared to healthy controls. NET is a protein that controls the re-uptake of norepineprhine form extracelluar spaces (spaces outside of cells). Seeking to understand why POTS patients would lower amounts of NET, researchers re-examined the expression of the gene in POTS patients and healthy controls. They discovered that, while the gene itself was normal in POTS patients (other than the one family previously mentioned), the POTS patients with reduced NET levels had an increase in chromatin modifications. Chromatin is the combination of DNA and proteins that allow DNA strands to wind up into tiny coils in the nucleus of a cell. Each human cell contains 1.8 meters of DNA, but when chromatin does it's job, that 1.8 meters of DNA gets wound up into a tiny little package that is less than .01mm in size, and fits neatly inside the nucleus of the cell.
Modifications in chromatin are known to cause changes in the way a gene is expressed. There is an entire field of genetic research dedicated to understanding changes in gene expression caused by mechanisms other than changes to the DNA itself. This is called epigentics.
This is really exciting research. If this study can be applied to the larger POTS population, in theory, it could lead to the development of a blood test to diagnose POTS some day, and perhaps even therapies aimed at correcting the abnormal chromatin structure.