Serene Forest

Saturday, October 14, 2017

How Many People Really Have Andersen-Tawil Syndrome?? More than 100!!


How Many People Really Have Andersen-Tawil Syndrome?? More than 100!!




Twice in the past week I have seen the inaccurate statement about only 100 people in the world having Andersen-Tawil Syndrome (ATS), the most severe and the most rare form of Periodic Paralysis. First, I read an article published just this week about a father and daughter who have Andersen-Tawil Syndrome and they explain that they are two of those 100 people! Then a few days later I received a request from someone who wanted to join our Support Group. This person is not diagnosed, but suspects the possibility of ATS and shared this with a doctor. The doctor had never heard of it and did an Internet search on a site only for doctors. He told her that she may be one of only 100 people in the world! This information is old, archaic, out of date, misleading and just not correct.

ATS is indeed very rare and there are few people in the world with it, but there are definitely more than 100 people who have Andersen-Tawil Syndrome.

For instance, in France alone, a study was done on people with ATS. Actually, 36 women, from 20 different families, from only 9 hospitals in France and who were diagnosed as carriers of KCNJ2 mutation, took part in the study. That equals 36 people out of 100 who have ATS in just one part of France. I imagine that each of those women had family members with it also...parents and children...so that would bring it up to at least 72 if there is at least one child per family and add the parent that passed it to them...that would be at least 108 cases!!!!!! That would be the least amount among those women. 

"We conducted a retrospective multicentre study in nine French hospitals. Patients were recruited only if they were KCNJ2 mutation carriers. Thirty-six patients (female n = 22, 61%) from 20 unrelated kindred ..."

There are people all over the world with ATS and each person has at least one parent with it (there may be a few spontaneous cases) and probably siblings and children. This is definitely more than 100 in the world.

We know now that ATS is also caused by the KCNJ5 mutation. These individuals must be figured into the equation too and about 50% of those who have ATS symptoms and a clinical diagnosis do not have a genetic mutation and are therefore not included in the count either.

More information to add to this equation:

Someone asked me, not long ago, if I knew how many people worldwide have Periodic Paralysis. I did not have an answer so I had to research it. The following is my best "estimation" based on the information I was able to find.

Orphanet, a consortium of European partners, currently defines a condition rare when it affects 1 person per 2,000. They list Hypokalemic periodic paralysis as a "rare disease".
(Source – Orphanet)

Prevalence rate of Hypokalemic Periodic Paralysis: approx 1 in 100,000 or 0.00% or 2,720 people in USA [about data]

Prevalence Rate for Hyperkalemic periodic paralysis: approx 1 in 200,000 or 0.00% or 1,360 people in USA [about data]

Prevalence Rate for Andersen-Tawil Syndrome: approx 1 in 60,000,000 or 0.00% or 4 people in USA. Source statistic for calculation: "100 people have been reported with Andersen-Tawil syndrome worldwide, Genetics Home Reference" (We already know this is not correct!)

According to this, in the United States there are 4,084 people with Periodic Paralysis. I assume documented, genetically confirmed cases.

But this does not account for those of us who are not genetically diagnosed and these numbers only account for the cases in the United States.

There are 7 billion people worldwide, so if I figured correctly according to the information above:

7,000=Hypokalemic Periodic Paralysis
3,500=Hyperkalemic Periodic Paralysis
100=Andersen-Tawil Syndrome
*** See below


10,600=cases of documented, genetically diagnosed people in the world have Periodic Paralysis.

But about 40 to 50% of individuals with Periodic Paralysis have no known genetic mutation, so that number should be about double.

So my best calculation, based on the above information, is that 21,200 people worldwide have Periodic Paralysis! This includes at least 200 for ATS! But, this estimate is very conservative. I am sure it may actually be a much higher incidence due to misdiagnosis and under diagnosis. Research would indicate that 200 cases is not even close to the number who actually have ATS in the world.

For instance, recently, some people in our support group received the results of genetic testing. One woman believed she had Periodic Paralysis. Several of her family members were diagnosed with Fibromyalgia and were content with that diagnosis. Just to humor their relative, they also had genetic testing done. ALL of them turned out to have the same genetic mutation for a form of Periodic Paralysis.

This woman had been told two months ago, by the most prominent specialist in the world for Andersen-Tawil Syndrome in Rochester, New York, after traveling at great expense across the country, that she DID NOT have Periodic Paralysis. 

Those three individuals would not have figured in the statistics, but now will be counted. This is just the tip of the iceberg!!!!! I believe that the number of individuals with Periodic Paralysis around the world is closer to 50,000 at the very least, but probably many more. And this is true for ATS…well more than 200!

(***This little exercise does not include the cases of Normokalemic Periodic Paralysis, Thyrotoxic Periodic Paralysis, Paramyotonia Congenita or a possible new form...Electrolyte Periodic Paralysis.)

More food for thought about Andersen-Tawil Syndrome and diagnosing:

ATS-like Characteristics of Periodic Paralysis

Andersen-Tawil Syndrome (ATS) is the most rare form of Periodic Paralysis. It accounts for approximately 10% of all periodic paralysis cases. It is characterized by three particular components: periods of paralysis from high, low or normal potassium levels, distinctive craniofacial and skeletal characteristics and long QT interval heartbeat with a predisposition toward life-threatening ventricular arrhythmia. However, affected individuals may express only one or two of the three components and they may be very subtle. Other characteristics and abnormalities are also associated with Andersen-Tawil Syndrome.

Although these characteristics are associated specifically with Andersen-Tawil Syndrome, in a survey of several hundred people with all forms of Periodic Paralysis, results for this category were very surprising. The majority, 92% of the members, reported at least one ATS characteristic despite the fact that only two members were diagnosed genetically and two members were diagnosed clinically. The majority of these characteristics were related to the fingers, toes and facial features. Many of the members shared photos of these anomalies. The photos were stunning. Compared to the photos in the medical journals, our members had much more pronounced curved little fingers and webbed 2-3 toes and craniofacial features.

These findings could not be dismissed as a coincidence.  There is a strong possibility that many of the ATS characteristics are quite possibly also seen in the other forms of Periodic Paralysis. Is it possible that these features or traits may have been overlooked in the previous research of patients with other types of Periodic Paralysis?

For this reason, we conclude these traits or characteristics are possibly more in-depth complications and they may be added to the list of symptoms and characteristics for clinically diagnosing all forms of Periodic Paralysis. This may be essential due to the complications some of these features, like scoliosis, dental anomalies, joint laxity, small jaws or issues with executive functioning may pose.

http://livingwithperiodicparalysis.blogspot.com/2013/12/what-is-andersen-tawil-syndrome.html

And so, the information about Andersen-Tawil Syndrome on the Internet needs to be changed to reflect what the truth really is about how many people actually have it. It is rare, yes, the most rare of the forms of Periodic Paralysis, but only 100 cases in the world??? I think not. There are more than 100 cases of ATS alone in France!!! What about the numbers of cases in the rest of the world???

This also demonstrates that most of the information that doctors are finding in their research on the Internet, especially about Periodic Paralysis, is probably also misleading and why we have such a difficult time with being diagnosed.




Until later.....


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