Testing


Diagnosis:

Physical Diagnosis: ECG, Echocardiogram, Holter Monitor, Stress Test: These tests may not give a true or accurate result at the time taken.

Genetics:

It is possible, although rare, that a mutant or altered gene has occurred after conception, but is usually inherited from one parent.  Each child has a 50% chance of inheriting the altered gene.   Each family is different and so are gene alterations, the mistake in the gene that may be responsible for Arrhythmia in one person therefore will be different in another. 

Although progress has been made and many genes have been discovered, it is vital that research continues in order to identify mutations that may not have shown at the time of testing.

Testing is an expensive process if the predictive gene test is not an option.  In other words, if a death is unascertained, family members are not automatically tested for an altered gene.

Genetic testing is limited at the moment, as 3 in every 10 people who are known to have LQTS (the most common form of Cardiac Arrhythmia) do not have mutations of the genes known to be associated with it. An additional problem is that most families who do have the mutations appear to have a specific change to the DNA code (known as private mutation).

The Myriad case: Genes are no invention!

Should this patent protection be removed in Australia, Genetic Technologies would benefit financially as it would no longer stand out as the entity in Australia paying royalties for tests such as BRCA (Breast Cancer).

"... you cannot patent something other than an invention. And a gene, even if it is isolated, is not an invention."
- Judge Sweet, Federal Court Judge of the US District Court
for the Southern District of New York.

NB: At Post Mortem - Testing can only check for known genes.

It is recommended that at State of Post Mortem, collection of a tissue sample ( 5-10ml of whole blood in EDTA tube, blood spot card, or a frozen sample of heart, liver or spleen) for all SUDS cases for subsequent DNA analysis/genetic testing.

If postmortem genetic testing were performed routinely, it is estimated that 25% to 35% of SUD cases from age 1 to 35 years may be due to mutations in one of the known channelopathy associated genes. *RYR2, KCNQ1, KCNH2, SCN5A* In intense cardiac testing of SUD victims living first degree relatives, a similar estimate of 25%>35% of those families being diagnosed with a heritable arrhythmia syndrome.

Identification of a cause of death has important implications for living relatives who may be at risk of developing the same disease. Concurrent cascade genetic testing/clinical evaluation in 'at risk' relatives is appropriate prevention strategy.

In autopsy-negative SUDS, ion channel genetic testing may be considered in an attempt to establish probable cause of death.

Mutation specific genetic testing is recommended for family members when identified as SUDS causative mutation.

*SUD: Sudden Unexplained Death

*First Degree Relative: Parent, sibling, child

*Mutation: A change of the DNA sequence

*Cascade Testing: When one family member is genotype positive, all first degree relatives are tested, with the process continuing with further genotype positive family members

*Genotype: A persons genetic or DNA sequence.