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Diagnosis Return to Index

Diagnosing FA
Who/Why/Where/How/What

Where did FA come from?
What is FA?
Who has FA?
Where does one do the DNA test(s) for FA?
Asymptomatic Testing

Your son or daughter has symptoms of ataxia (incoordination) or scoliosis or hypertrophic cardiomyopathy and your doctors have been trying to "name the blame", what is it they have? Could it be FA?

The search that leads to FA is not an easy one. Look at this shortened 2007 presentation from the wonderful UCLA Dr. Susan Perlman, 2007 Dr. Perlman Diagnosis Only Presentation that covers many of the alternative diagnoses and FA DNA diagnosing. Also in the FARA "Clinical Care Guidelines", FARA Clinical Care Guidelines, section 1.5 "Differential Diagnosis" there is an excellent coverage of alternate diagnoses.

Where did FA come from?
The FA gene is European in origin and its first incidence goes back many millennia, so one would expect the greatest FA density to be in European settled areas (USA, Canada, Australia for instance) with the least density in areas such as Africa, South America, and China for instance. Take a look at the FAPG map to prove this out.

What IS FA?
FARA has a good set of web pages at http://www.curefa.org/whatis For a layman's rendition of what FA is see What is FA.

The FA gene can err in one of several ways. It can have an abnormally long GAA sequence or it can have a mutation in the gene called a point mutation or axon deletion. About 96% of FA'ers have two abnormally long GAA repeats from around 60 repeats to 1700 repeats. The other 4%-ish have one or more point mutations (or axon deletions which are exceedingly rare and not covered here). So when one wants a DNA test for FA the first and least expensive test is for 2 expanded GAA repeat genes. If that comes back negative or just one expanded GAA repeat gene then do the more expensive test for point mutations. The third test for axon deletions is then even more expensive.

Who has FA?
Before 1996 FA was diagnosed by symptoms. This started in 1863 when Dr. Friedreich isolated the symptoms of FA. In 1996 the location of the gene that causes FA was identified (9q21.11) and a DNA test shortly thereafter was put in place.

The FA carrier incidence rate varies from country to country and by sub-population. If you are in the "Cajun" area of Louisiana the rate is 1/40 people, but if you live say in the middle of China the rate would be very, very low, say 1/10,000 to 1/100,000 (purely a guess on the author's part - a negligible chance). The average in European family trees is about 1/100.

The chance for two "average" FA carriers is about 1/100 times 1/100 or 1/10,000. If they have a baby the baby's chance for FA is 1/4.

So the chance for a FA birth in an average European-descended family is somewhere around 1/40,000 (FARA uses 1/50,000).

Where does one do the DNA test(s) for FA?
Once one suspects FA it is DNA test time! But where? Your doctor may know and your medical insurance may pay for the testing. That would be good. In case YOU have to pay for it or your doctor doesn't know or you want an anonymous test here is a sample list of DNA test centers.

  • In the USA
    • The two "commercial" labs most mentioned in FA testing are Baylor Medical Genetics and Athena Diagnostics. Baylor is much lower cost than Athena. There are also several (at least) university and hospital labs that have some test capability but most use the capability for research purposes. And they do so few tests that the quality can suffer. I happen to know that CHOP (Children’s Hospital of Philadelphia) uses Baylor for a lot of their testing because the cost is lower and for a positive reading they call the doctor right away which is much faster than the written report.
    • CHOP also uses 2 other labs, Gene DX and MNG Labs. But neither directory lists FA? And they are good for only the expansion test and not the sequencing test (point mutations). I would stick with Baylor (preferred) or Athena.
    • So,
      • First, check with your insurance to see if they will pay for any testing (FA'er, siblings or parents).
      • Second, ask yourself if an anonymous testing would be better? Once one is confirmed FA then life insurance and long term care insurance goes out the window. Even if one is confirmed as a carrier there is still the possibility of life and long term care insurance acceptance rejection (insurance companies are fickle). Right now even having a pre-existing medical condition for medical insurance acceptance has been put on the federal government table to be axed. Not much can be taken for granted.
      • Third, check pricing. Here is the November 9, 2018 "cash" list pricing for Athena and Baylor:
        --------------------------
        1. Athena Diagnostics - 1-800-394-4493
        Test information (Search for Friedreich): http://www.athenadiagnostics.com/content/test-catalog/
        Friedreich Ataxia DNA Test 119 (expansion test) $1120.00
        Friedreich's Ataxia DNA Sequencing 348 $2400.00
        Friedreich's Ataxia Profile 349 (both expansion & sequencing) $3205.00            
        Requisition form:
        http://www.athenadiagnostics.com/ordering/supplies/requisition-forms

        2. Baylor Medical Genetics - 1-800-411-4363
        Test information: https://www.bcm.edu/geneticlabs/test_detail.cfm?testcode=6031&show=1
        Friedreich Ataxia Repeat Expansion Analysis, Test Code: 6031 $380.00
        FXN Sequence Analysis, Test Code: 6365 $780.00
        Both expansion & sequencing as a package? No.
        -------------------------------
        Both companies have a financial aid program based on income and number of people in the household. Athena’s program brings the cost to a range of $100 - $800. I didn’t ask Baylor.
      • Fourth, decide whether you want just the expansion test or also the sequencing test. 96% or so of FA’ers have 2 expanded GAA repeat genes, BUT the remaining 4% have one or both genes with a point mutation. It’s a serious game of probability risk vs. cost. The investment of an extra $780 at Baylor’s gives you complete confidence the tested person does not have any kind of FA gene if both tests come back negative (ignoring an axon deletion). If you do only the expansion test you will have the nagging worry about that pesky 4% point mutation risk. It’s your decision.
      • Fifth, contact your doctor to communicate what you want done and how. Most doctors can do anonymous testing. Ask what their procedure is. Some will send you to a blood lab like Quest so you will need to be VERY sure communication is clear with BOTH your doctor and the blood lab as to who you want the blood to go to, the exact test code(s), and the anonymous question.
  • Outside the USA
    • There are many countries outside the USA and many of them have resources to do DNA testing. But from within FAPG we do not get much visibility on those test centers. This Orphanet link has a rich list of accredited test centers and can be further sorted.

    Below is a list of labs used by FAmilies.
Asymptomatic Testing
Welcome to another judgement-call gray area in FA! The question of when and who to test for a disease/disorder with no governmentally approved treatment comes fairly quickly for a newly diagnosed FA family with more than one child, and later when siblings want to choose someone to have children with or extended family wants to know if the carrier gene is floating on their side of the family tree.
  • Siblings
    • The traditional geneticist ethic for a condition with no treatment has been to not test the siblings because of the possible negative emotional response short and long term on the person and their family to knowing for sure one has the condition.
    • The FARA FA Clinical Guideline covers genetics in Section 6 starting on page 154. For testing siblings the 39 doctors could not achieve consensus, reflecting the gray nature of this question.
    • In FAPG there have been a number of discussions about testing asymptomatic siblings, also reflecting the gray nature of the question.
      • Reasons to not test:
        • No approved treatment
        • If they have FA let them be normal while they can
        • Parent
          • Cannot bear to know
          • Has too much on their plate dealing with one FA'er
        • Possible impact on life or long term care insurance if found to be a carrier.
      • Reasons to test:
        • Emotional pressure of not knowing is worse than knowing
        • Can better plan for the future
        • There are a number of supplements and drugs that anecdotally have been reported to make a (small?) difference in symptoms and/or potential FA progression. If such "treatments" are given in advance of symptoms will that delay the FA onset? For one FAmily, the Helms, when their 6 year old son was diagnosed they decided to test the 2 year old sister and it came back positive. Their GAA repeats are almost identical. 11 years later they report:
          ----------
          As for the present, Sienna (just shy of 13) just finished her travel volleyball season where she played and contributed very much on a team with 13 and 14 year olds. She's currently playing softball where she is hitting, throwing and catching at a level consistent with her peers. For comparisons sake, at 12/13 years old Dylan was using a wheelchair full time and had just had scoliosis surgery. Sienna sees a cardiologist once a year, has her A1C checked once a year, and scoliosis checked once a year. Her heart is totally normal, A1C is slightly elevated, and mild scoliosis that is consistent with teenage girls. She has been on Idebenone and Niacinamide since she was 2 years old with minimal to no side effects. One consideration that Dr. Perlman did suggest was the different body types - Dylan is tall and thin while Sienna is shorter and stockier. Their repeats are essentially identical. As parents we have noticed some subtle things with Sienna. She is somewhat clumsy when she's not paying attention and she does fatigue with a lot of running or having to walk thru snow (we do live in Montana). Day to day activities she still appears asymptomatic though.

          Dylan is progressing. His fine motor skills are deteriorating which affects much of what he used to like to do with video games which is frustrating. He's got a good group of friends that he enjoys playing games with and some good people at school. FA is tough for him though.

          Please feel free to include our names and contact info with the article you are posting. We would be more than happy to talk/email/whatever with anyone that would like to hear more from us. We whole heartedly believe that early intervention has helped delay the onset of significant symptoms with Sienna for the sole reason that we nor (Dr.) Perlman nor (Dr.) Lynch have any other reasonable explanation.
           -----------
          Sienna's experience cannot be guaranteed for other asymptomatic FA’ers but it is certainly interesting.
  • Extended Family
    • Section 6.7, page 159 of the FARA Clinical Care Guidelines covers this nicely.
    • In the USA remember to be sensitive to the (low?) risk of being rejected on life and long term care insurance coverage if one is found to be a carrier. Anonymous DNA testing is the alternative to consider.
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