Diagnosing FSHD: what are the steps?
The diagnosis of FSHD is more than just getting a simple blood test. There are a number of steps that you will need to take to get to the answers you want. Your doctor will be able to help you through all of this.
Finding the right health professional
If you think you have FSHD you should ask for a referral to a specialist. It can be challenging to find a specialist in your area. However, your GP should be able to help you find one. A specialist with experience in neuromuscular disorders will probably be the most helpful for you. You could also consider seeking out a clinical geneticist who will have experience in diagnosing genetic conditions.
Most importantly, if you suspect you have FSHD then ask specifically to be tested for it. Genetic tests need a target gene to test for. If you do not mention FSHD then you may end up being tested for mutations in genes involved in other neuromuscular disorders.
A genetic counselor will also be able to help you understand the diagnostic process and be able to give you support.
Stepping through the process
Diagnosis of FSHD is a combination of physical examination to assess muscle weakness, neurological examination to rule out other causes of weakness, and molecular examination to determine whether disease-causing mutations are present.
There are a number of ways to approach the diagnosis of FSHD. The simplest is through a blood test where your genetics can be assessed. The only test that can diagnose FSHD and rule out other causes of muscle weakness is a genetic test.
Progressing straight to a genetic test may be appropriate for some people such as those with typical symptom pattern and some history of FSHD. For many people it makes more sense clinically to perform some other tests before going to assessment of genetics.
If you have the typical pattern of symptoms expected of FSHD and a first degree relative (a person’s parent, sibling or child) with genetically confirmed FSHD then proceeding to a genetic test is probably unnecessary. Family history and evidence of symptoms is sufficient to confirm an FSHD diagnosis.
The diagnosis of FSHD may include some of the following:
● Physical examination to determine the pattern of weakness, the muscles that are involved and the extent of the damage.
● Blood test to look at the levels of creatine kinase. This is an enzyme that gets released into the blood when muscle tissue breaks down. Elevated creatine kinase is an indication that there is muscle damage. However, it is not specific to FSHD, many other conditions are associated with elevated creatine kinase.
● Tests that look at the electrical activity in the muscles (electromyogram) or the nerve conduction speed may also be done.
● MRI is increasingly being used in assessment as well. However, this may not be available everywhere.
● Muscle biopsies may also be taken to see if there are any cellular abnormalities present in the muscle tissue. However, muscle biopsies are not used very often now and it is unlikely your health professional will suggest one.
Genetic testing for FSHD
If you decide to go ahead with genetic testing there are a number of options and things to consider.
The cost of getting the test done will depend on where you do it. Some tests will be provided free of charge if you are being seen in a public hospital. However, some facilities may not offer this, and there may be a charge for getting the test done. You should ask your care provider what the costs are before agreeing to the test.
The technical information
At the moment it is most common for people who are displaying symptoms associated with FSHD to be tested for contraction of the D4Z4 region on chromosome 4. How contracted this region is will tell you how severe your symptoms are likely to be with a smaller number of D4Z4 repeats associated with more severe symptoms. However, this is not a perfect measure of disease severity, so at the moment it is not possible to tell someone exactly how their condition is going to progress by measuring the size of the contraction.
Measuring the contraction of the D4Z4 region is done by cutting up the DNA at specific points inside the area and performing what is called ‘Southern Blot’ analysis. This technique allows you to measure how many D4Z4 repeats a person has. Less than 10 – 11 repeats is considered a definitive diagnosis of FSHD.
Testing of FSHD2 is more complex because there are a number of genetic factors that cause the symptoms. At the moment the DNA sequence is read using a method called next generation sequencing. This is a high throughput technique that is very effective. However, it may not cover the entire genomic region that needs to be covered to pick-up mutations. Some disease causing mutations may sit well outside what would normally be sequenced and would therefore be missed. At the moment testing for FSHD2 is not available in Australia. If you are interested in being tested for FSHD2 please contact the Foundation for more information.
All genetic tests for FSHD that are being used at the moment have limitations. There is a chance that your test result will come back negative for FSHD when in fact you do have the disease causing mutation. There is also a small chance that you may get a positive test result when in fact you do not have FSHD.
Hope for better technologies
New technologies such as whole genome sequencing offer hope for better diagnostics, particularly as all genes can be investigated at once. These technologies are being improved upon constantly, but they are still not perfect. Other methods include measuring methylation. Methylation is one way cells use to turn off certain genes. In people without FSHD the D4Z4 region is off and has a lot of methylation. For people with FSHD the amount of methylation goes down. Methylation is a powerful method for diagnosis and can be assessed in blood or saliva samples.
These methods are still being developed, but it is hoped that an effective, robust diagnostic will be available in the very near future. The Foundation is committed to bringing quality diagnostics to people in Australia. In 2016 we have committed significant funds to set up a centre of excellence in diagnostics in this country with the aim of making a genetic diagnosis of FSHD easier for all Australians.
Getting the result
Getting a test result back is only the start of a journey for someone with FSHD. According to our 2016 Consensus statement people with a suspected diagnosis of FSHD should have access to a clinical geneticist with experience in neuromuscular disorders and a genetic counsellor to help you and your family process the diagnostic result.
A positive test
Getting a positive test result means you have a confirmed diagnosis of FSHD. Your specialist should provide you with significant support over this time to help you understand what this means for you and to connect you with other health professionals and services that you may need as your condition progresses.
While there are currently no approved drugs for FSHD there are still a lot of things that can be done to help support you.
A negative test
A negative test may be met with mixed emotion. For people with symptoms this means their journey to find a diagnosis continues. This can be frustrating.
It’s important to note that the tests that are currently available are not perfect. A negative test does not necessarily mean you do not have FSHD. If your symptoms continue to progress in the absence of any other explanation you may want to consider repeating the test.
Misdiagnosis is a common issue experienced by people with FSHD. We have had reports from our community that they received diagnoses for multiple sclerosis, other types of muscular dystrophy, fibromyalgia or simply told there is nothing wrong. Do not be afraid to seek a second opinion, or ask for further clarification on a diagnosis.
HUNTING FOR A DIAGNOSIS
Common misconceptions experienced by people with FSHD
‘You can’t have FSHD, only males get FSHD’
The muscular dystrophies are a diverse group of diseases that cause muscle wasting. Each is a unique disease with a unique disease mechanism. Unfortunately there is a propensity to group them together and assume they are all similar.
People often assume that muscular dystrophy is something that only affects boys because of Duchenne’s Muscular Dystrophy (DMD). The reason DMD affects mainly boys is that the gene involved (dystrophin) sits on the X chromosome, or the female sex chromosome. Female children have two copies of dystrophin, to develop DMD you need two mutated copies. Having two mutated copies is rare and therefore DMD is very rare in females. For boys, who only have one X chromosome, if that copy of dystrophin is mutated they do not have a back-up copy to prevent the development of disease.
Most health professionals would have studied DMD during their training because it has several features that make it an excellent teaching tool for students to understand genetic basis of disease. Because of this they may think that DMD is the most common form of muscular dystrophy, or even assume that the features of DMD are shared by all other dystrophies. Some people may also be unaware that there are actually other muscular dystrophies.
Of course, FSHD as well as other dystrophies are equally likely to affect males and females because the genetic defects do not sit on the X-chromosome.
‘You can’t have FSHD because you don’t have *common symptoms*’
The term facioscapulohumeral dystrophy was introduced in a 1950s scientific paper where researchers had studied the typical pattern of inheritance and symptoms of this dystrophy in a large family.
This pattern of symptoms being facial, shoulder and upper limb weakness. However, even in this publication the highly variable way FSHD manifests was observed.
The symptoms used to clinically identify FSHD may be what is usually seen, however, they should not be used to rule people out of a diagnosis of FSHD.
‘You can’t have FSHD, you don’t have any family history’
FSHD is a genetic condition that is passed from parent to child. However, a significant minority of FSHD cases are what is known as ‘sporadic’. That is, a mutation that happens spontaneously and is not inherited from your parents.
Family history may help identify conditions that should be investigated when someone presents with progressive muscle weakness, but lack of family history should not be used to rule people out of a diagnosis of FSHD.
‘There are no treatments for FSHD, so why do you want a diagnosis’
Access to treatment is only one reason to have a diagnosis. There are many reasons why getting a confirmed diagnosis is important to people.
1. Giving your condition a name is powerful – it means you have an explanation of the symptoms you are experiencing. It can mean being able to tell your workplace exactly what is wrong, empowering you to ask for assistance.
2. Having a diagnosis means that you have a clearer idea about what your future may look like, and the opportunity to plan for that future. For example, does your home have stairs or poor access points, is your workplace accessible, are you planning on starting a family? There may not be any treatments available at the moment, but that doesn’t mean that there aren’t things that can be done right now to improve your quality of life and prevent deconditioning and deterioration.
3. Many assistance measures that are available for people with a disability are only open to those with a confirmed diagnosis. Things like access to personal care assistance, employment assistance and other medical benefits may only be available if you can present evidence from your doctor confirming you have FSHD.
4. Access to clinical trials. Many trials require genetic confirmation of FSHD before they will consider you for clinical trials. If you would like to be involved in trials it may be a good idea to get a confirmed diagnosis. Clinical trials give you access to new treatments being developed for FSHD very early in the development process.
‘Getting a diagnosis of FSHD will affect my health insurance’
The laws governing health insurance are clear. Insurers must continue to provide cover for people who have pre-existing medical conditions. Premiums for private health insurance will not be affected by a genetic diagnosis.
What will be affected are policies like life insurance. The Centre for Genetics Education has a fact sheet detailing the effects of a genetic diagnosis on insurance.
FSHD Educational Toolkits
These free and accessible toolkits are for people living with FSHD, GP’s and Allied Health Professionals. They are designed to help you understand the mechanisms of FSHD, symptoms, diagnosis, testing, the effective management of FSHD and give you handy tips on how to make your appointments more productive.
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