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Ataxia Support Network

Genetics?


#1

Hi everyone,

My mother-in-law recently passed away from an atypical spinocerebellar ataxia at the age of 59. The orphan disease which caused the ataxia was never diagnosed.

Her neurologist performed a few DNA tests with no conclusive results i.e. unable to confirm if the ataxia was genetic or not.

No one in her family has ever had ataxia. Although she had a cousin with MS.

In doing online research it says that all spinocerebellar ataxias are genetic… so why is the neurologist unable to confirm that?

This information is conflicting - can anyone shed light on the situation?

Also what are the chances that my husband develops ataxia?

This is a scary illness, you are all warriors.

Tx for your help

Dina


#2

Hi…my neurologist who is the hospital’s director of the movement disorders center where I get treated said to me point blank that genetics is not his forte. He referred me to a specialist in genetics who performed the DNA test- I don’t recall the name of it, but do remember it was about a 14 panel test. There are one’s with many more panels. It was the genetics doctor who gave me my diagnosis of SCA3, and told me that it was definitely a hereditary disease. I’m adopted, so I have no idea as to my biological family history. Perhaps you might want to find a genetics specialist to talk to.


#3

Hi,
Thank you for your response!
I will look into chatting with a genetics specialist.
Is spinocerebellar ataxia from a dominant gene or recessive?
In my mother-in-law’s case, seeing as no one in her family had it, or would it be from a recessive gene??
Tx for your help!


#4

Hi Dina :slightly_smiling_face: Autosomal dominant - Autosomal means that both males and females are affected. Dominant means that each child of an affected individual (only ONE parent needs to pass on the gene) has a 50% chance of inheriting the genetic change that causes ataxia. The dominant Ataxias are labeled ‘Spinocerebellar Ataxias (SCAs) and are numbered in order of their discovery ( SCA1 was the first, and as of 2017 SCA43 was the most recent, but since then I recall people mentioning other recent discoveries.
Autosomal Recessive - Autosomal, again this means that both males and females can be affected. Recessive means that in order to have the disease, a person must inherit a genetic change (mutation) from BOTH of their parents. This form of ataxia is labeled SCAR followed by a number. If a child inherits a mutant gene from both parents, they will go on to have ataxia. But if they inherit just one of the genes, they will be a ‘carrier’ and therefore unaffected. However, if they as carriers go on to have children with someone else who is a carrier, it’s possible the children will be affected. Inheritance in this form could go on for decades until two carriers come together, and the disease manifests.
And there are other recognised patterns linked with inheritance.
Genetic tests can be very difficult to interpret. Therefore, it is important to do genetic testing in consultation with a health care provider who is familiar with how to interpret genetic testing results. Diagnostic testing is usually done in situations where a patient has symptoms of ataxia, and the testing is done to try and find out the precise genetic cause. In some cases, diagnostic testing will find out a specific cause for the ataxia, while in other cases, it may not find out the cause. If the results of diagnostic testing are normal, this does not mean the diagnosis of ataxia is wrong. It just means that the specific cause couldn’t be identified using current technology. A few years ago, at a Convention, there was a report saying that to date almost 100 SCAs had been identified, with even more expected. But, many of them are still waiting for a test to be devised for patients.
Whole Genome/Whole Exome Sequencing - In the past, each ataxia has had to be methodically tested one at a time. Genetic testing options are now available that can test for hundreds ( or even thousands) of genes at the same time. Such testing may be an option if a genetic cause is suspected, but traditional genetic testing has not been able to identify the cause of ataxia in a patient. Whole Genome Sequencing looks at all of the DNA in your body. In contrast, Whole Exome Sequencing focuses on a small part of the Genome that encodes our genes. Most of the mutations that are known to cause ataxia lie within the smaller Exome Sequence. Currently, Whole Exome Sequencing is available at many clinical laboratories, while Whole Genome Sequencing is very limited.
Laboratories use a technology called Next Generation Sequencing when performing such specific tests. Older Sequencing technologies were very costly and labor intensive. Next Generation Sequencing is a new way of doing genetic testing that allows scientists to look at large numbers of genes in a cost effective way.
I hope this explanation has helped :slightly_smiling_face: xB


#5

Hi Beryl!

Thank you for the response! Very helpful in differentiating dominant from recessive.

If I may ask your opinion on something:

Seeing as my mother-in-law had no history of spinocerebellar ataxia and was the first to get it… does this mean it was inherited due to an anomaly in genetic mutations or?

Because I don’t get how it can be genetic but she’s the first to ever get it.

Sry for all the questions, just wishing to educate myself.

God bless


#6

In other words, if no one in her family had it, she has autosomal *recessive spinocerebellar ataxia?


#7

That sounds very possible. Or, she could have an acquired ataxia for another reason. If her parents died young, they may not have had time to develop their ataxia. All the confusion is why your husband really needs a geneticist.


#8

Hi Linda,

Thank you for your response.

Unfortunately, he does not want to do genetic testing… but in the meantime, I am trying to understand as much about this mysterious condition as possible.

I didn’t think there were other ways of acquiring spinocerebellar ataxia, since there is an emphasis on it being strickly genetic… where as other ataxias can be acquired due to environmental factors?


#9

Hi Dina :slightly_smiling_face: It is always a good idea for a patient to do research in order to try and understand the complexities of Ataxia. But when you surf the Internet, there can be a lot of medical jargon to contend with, and it’s very easy to misunderstand and get sidetracked.

When it comes to patients, most people just say I have ‘Ataxia’ but there are so many different types, and causes. Cerebellar Ataxia has many different causes, but it is not genetic. Spinocerebellar Ataxia is caused by a mutant gene, and is genetic. Both of these can display very similar basic symptoms because in both cases the Cerebellum is damaged.

You might get a better understanding of how these conditions can effect a person by
logging onto www.ataxia.org and clicking on ‘what is ataxia :slightly_smiling_face: xB


#10

I don’t know if this is the reason why I developed Ataxia but it’s the only thing that comes to mind. Let me start by saying that no one in my family has it! While I was in the US Army, I was stationed in Panama. Because Panama was a known area for Malaria, the military sprayed DDT every day to control the possibility.

I never showed any signs growing up and I passed the physical to enter the military. After 1 1/2 years in Panama, I started showing minor signs of Ataxia shortly before my military separation. I went to sick call but they thought that problem was in my eyes only and that they were just tired.

After separation, the minor signs never went away and started to exacerbate. I was initially diagnosed with MS. Many years later since medical technology advanced, my diagnosis was changed to SCA - where it is today.

EDIT: I never had or am interested in any genetic testing. I am only interested in getting my life back. I don’t mean to step on anyone’s toes here.


#11

Hi Chas!

Wow! That is so fascinating! That’s what I’m saying… how come people with no family history are diagnosed with something genetic?!

Stay strong :pray:t4:


#12

Hi Beryl!

Thank you for your incredible insight!

It just dawned on me the difference between genetics and hereditary!!

So SCA is genetic, not necessarily hereditary!


#13

:thinking: For years to come, realistically speaking, it’s possible that many of us here will continue to hypothesise as to how we came by this condition/disease that goes by the name ‘Ataxia’ :smirk:
Many’s the time I’ve thought various accidents I’d had over the years had triggered the ‘ridiculous symptoms’ that were cropping up. At one time I was convinced a specific Medication had caused the onset of my Eye problems, but I couldn’t prove it… My Mother had similar Eye and balance problems, but the onset was in the early 1960s and at the time she was never tested for Ataxia. But, could there be a link :thinking: My cousin had Muscular Dystrophy, is it possible there could be a link of some sort :thinking:

After over 15yrs of puzzling symptoms, I was asked to donate DNA for a special project, my whole Genome was tested, and voila!! a link with something was found :+1: I really thought that it was the answer to my prayers, but it just seemed to muddy the waters further, it wasn’t 100% :hushed: The findings pointed towards being genetic, so I started worrying about my children inheriting, but my Neurologist dismissed my concerns because the link was with a Recessive mutant gene, and after all it wasn’t even 100%…
:thinking: xB


#14

You’ve asked a very good question. It seems to me that when the medical community is stumped, they say something that has folks scratching their heads LOL.


#15

thanks @Beryl_Park for your continuous insights and explanations.

may I add, that there is some patients that are concerned about the “chemical” aspect that seems to be the possible cause/trigger for Ataxia ?

again further research is warranted, on all fronts.
and Yes, research is moving fast and so new strains are being found


#16

Hi Dina,

I’d like to take a “whack” at your questions. You asked:

  1. Why couldn’t your neurologist confirm a genetic cause?
  2. What are the chances of my husband developing ataxia?

For the first question I believe Beryl laid out a excellent and comprehensive overview of the topic, but the fact maybe quite simple that the genetic tests all came back negative, and you should ask your neurologist why he/she believes it was potentially genetic. I suspect it comes from an opinion based on symptoms. Perhaps the neurologist is unaware of how frequent idiopathic Ataxia is. Idiopathic means Ataxia with no known explanation. The fact is if your mother was screened for all the known Ataxias and the tests came up negative then her Ataxia MAY NOT have been genetic. Do you have symptoms? If you did that would lend some credence to her neurologist’s diagnosis, but if you do not have symptoms and are simply worrying about whether or not you will be impacted, I urge you to find support to help you to not worry about something that is beyond your control and if it wasn’t genetic then you are highly unlikely to have the same illness.

On your second question, Ataxia is extremely rare so unless there is some family history you didn’t mention the chances of your husband having Ataxia of any form are remote. Really remote.

All the best,

Joe


#17

Hi Joe,

Thank you for your response and thank you to everyone for your feedback. It’s been very helpful!
I believe you are right in your assessment.
In fact, my mother-in-law’s neurologist thinks her spinocerebellar ataxia was “sporadic” and is not too concerned about transmission.
Her case deteriorated in 10 years, but I wonder if that’s because she gave up… didn’t do physiotherapy or anything…
Is there anything people can do to maintain health with ataxia?

Thank you

Dina


#18

There is a lot we can do to maintain our health. Unfortunately, it all comes down to eating healthy, exercising, getting checkups, getting needed vaccinations, getting dental care and all the normal, boring stuff. Many find that working with a physiotherapist is helpful. Nothing cures the ataxia, butbeing as healthy as possible is good.

Changing subjects, I know exactly how I got my ataxia. It was surgery over 8 years ago for brain cancer that was in the brain stem and cerebellum. I don’t know of anything that happened or was done wrong. I just wasn’t lucky.