Why haven't they done genetic testing?

Hello All,

Although I have written a few articles about diagnosing, I decided to write one more…

One of our members was going through some medical testing working towards getting a concise and much needed diagnosis for Periodic Paralysis. The test measures nerve conduction and is predictably painful. The results may or may not detect Periodic Paralysis. As she was in tears and only half done with the testing, the doctor feeling sorry for her asked her asked, “Why haven’t they done genetic testing?” He then decided not to complete the test, much to the relief of his patient. Though the doctor had the best of intentions, he did not understand the problem with seeking and receiving a concise diagnosis for one of the several known variants of Periodic Paralysis.

 
This is my response to the doctor:

"Why haven't they done genetic testing??" Really???  Maybe because it does not matter because only 50% of us have a mutation that has been discovered and the testing at best is narrow and biased let alone expensive and virtually non-existent!!  Genetic testing gives no guarantee for receiving a diagnosis.  At this time, diagnosing for Periodic Paralysis must be based on an individual’s symptoms and characteristics, depending on the type they have.

 
According to the American Heart Association, ”The approach to genetic studies of complex traits entails candidate gene or genome-wide association studies. Genome-wide association studies provide an unbiased survey of the effects of common genetic variants (common disease–common variant hypothesis).”

“Based on today’s knowledge, only 1% of the human genome is transcribed into mRNA and translated into proteins. An additional 0.5% serves as a template for noncoding RNA and the regulatory regions that control gene expression.⁵ The functions of the remaining 98.5% of the genome including functional conserved noncoding elements, which comprise at least 6% of the genome,⁶ remain unknown. Hence, this large segment of the genome is referred to as the dark matter of the genome.”

http://circres.ahajournals.org/content/108/10/1252.full

This would indicate that genome-wide genetic testing would be the best way to test for the various forms of Periodic Paralysis (PP), but since only 1% of human genome has actually been transcribed, it also indicates why more than half of those tested get negative results. The research labs run testing only for the tests requested by the doctors ordering them. If testing for only one form of Periodic Paralysis is requested, that is all that will be checked.

When genetic testing was being done in Germany and blood was sent overseas for testing for Periodic Paralysis, only the known mutations were searched for and they were either found or not found. There was no research done on what mutations on the same gene in the same exons or locations meant nor did they report those findings on the results if they were found in the denial letter sent to the individual. This is definite “bias” in the testing. One is left to believe there is no reason for their symptoms and to wonder about their own sanity. An individual’s doctors, not understanding the above information, believe that the person does not have Periodic Paralysis. At this point the 'conversion disorder' diagnosis is usually given.

The genetic testing for Periodic Paralysis in Germany has been discontinued since June 30, 2014.  But I know that when it was being done, the testing did not test for every known variant of PP because I have a copy of the letter from them telling me which genetic mutations were tested. I also have a copy of my own whole genome testing which includes ALL of my known genetic mutations.

My genetic mutations indicate that I have a form of Periodic Paralysis, Andersen-Tawil Syndrome; a new, less known form and Paramyotonia Congenita (PMC)/Hyperkalemic Periodic Paralysis which was discovered on an exon not looked at in Germany, but known to be a mutation which was involved in PMC.

Studies indicate that it takes an average of twenty years and is certainly very costly for someone with Periodic Paralysis to get a diagnosis. This is ludicrous and unconscionable. During those years an individual gets worse. They develop exercise intolerance, permanent muscle weakness, heart issues, breathing issues and are harmed from unnecessary medications. Some may even die.  Those twenty years or more consist of seeing doctor after doctor, specialist after specialist; taking test after test, because it is a condition in which a diagnosis is obtained by exclusion, it is diagnosed after everything else is ruled out. Really?? How many diseases do you know that cause a person to have intermittent paralysis??? I only know of one...Periodic Paralysis!!!!!!

 
Besides taking a long time it is very, very costly. I myself did not get a diagnosis until the age of 62. Some of our members in their eighth decade are still trying to get a diagnosis. Many die without a diagnosis, some very early in life, while trying to get a diagnosis. My own great uncle died at the age of 41 during an episode.

So, in conclusion, there is only a 50% chance that if an individual has genetic testing done a genetic mutation will be discovered. This chance reduces considerably when the testing done is biased and narrow.  Whole genome testing by the correct and reputable lab may provide some answers but it is not certain that a diagnosis can or will be made. It is very expensive and most doctors will not order it nor will many medical insurance companies pay for it.

Periodic Paralysis needs to be diagnosed clinically, based on an individual’s symptoms and characteristics.


Until later...