It’s in your genes

9 August 2020

While browsing the internet recently I came across an advert for genetic testing which led me to think whether it would be beneficial to me to get genetic mapping or testing done.

Over the last few years many people have seen these tests advertised and are wondering -is it a good idea? Is it ethical? Will it be beneficial to know, or prove problematic, for instance, when getting a health insurance quotation?

A relatively cheap and simple test that can be done is drug-gene testing, also called pharmacogenomics, or pharmacogenetics testing. Pharmacogenetic tests cost around $200, but as yet are not commonly covered as part of general health-care provision. What are the benefits, if at all, of such a test, and what does it involve?

Pharmacogenomics is an emerging field, looking at how genes affect an individual’s response to medicines. Several genes have been found to affect a person’s response to medicines, as some genes control the production of specific drug-metabolizing enzymes. As such, their presence can influence overall response of a patient to their drug therapy. The effect of their presence or lack of it can lead to various types of Drug Related Problems. Based on the variation in a specific gene and the associated metabolizing enzymes, a drug could be either simply ineffective, or the opposite, to present an increased effect, to the point of  an accompanying adverse drug effect, resembling an overdose.

Which genes are important in pharmacogenomics?

The most well-known of these “pharmacogenes” are the Cytochrome P450 genes (including CYP3A4, 2D6, 2C9 and 2C19). These can account for interpatient variability in drug metabolism of over 25% of medicines in clinical use. There are also drug transporter genes (i.e. SLC01B1 which encodes the OATP1B1 transporter responsible for uptake of statin drugs into the liver) and Human leukocyte antigen-B (HLA-B) genes, which have been associated with causing ADRs in a number of common drugs, such as allopurinol and carbamazepine.

What’s the point of pharmacogenomic testing?

The goal of integrating pharmacogenomics into routine practice is both to provide a large number of patients with safer and more appropriate therapies, and to avoid wasting time and money on treatments that will be at best ineffective, and at worst – harmful. Many in healthcare believe that the cost of testing will be offset by the money saved, and there is much debate about whether this testing should be offered free of charge to patients by healthcare funds/insurance in the future.

Where can I get a pharmacogenetic test?

To date, pharmacogenomic testing has mainly taken place in academic science centers, where cohorts of patients were tested for the presence of the relevant pharmacogenes on admission. The results were then added automatically to the patient’s profile in the EMR, which could then be accessed by clinicians to improve patient’s individual drug therapy.

However, currently there is a push worldwide to provide pharmacogenomic testing in the community setting. Today’s commercial tests are available in the form of a simple cheek swab, with no painful injections required. These simple tests are being offered by community pharmacies where patient consent is obtained, and the results can then be followed up and actioned by the patient’s physician or a trained pharmacist. The clinician will look at relevant patient factors (such as age and lifestyle factors, such as smoking) and manually perform a thorough medication review. Currently pharmacogenomic treatment decisions are most likely to affect the clinical areas of cardiovascular, psychiatry, gastrointestinal, infection and malignant disease.

Pharmacogenomics and the EMR

An emerging option to leverage the genetic testing is available to the clinician as part of the use of electronic clinical support and prescribing systems. Via Seegnal, a smart patient-specific clinical support platform, the clinician can easily identify and resolve, at the touch of a button, any needed changes to patient’s therapy due to their genetic profile. Seegnal also offers effective alternative therapy or dosage regimens if necessary.

Future developments in the area of pharmacogenomics are likely to involve pro-active screening of patients, in order to predict and flag to the clinician which patients are most likely to need an adjustment to their therapy due to genetic variability.

Once you agree to a genetic profile test, the result can be stored and as your genetic makeup does not change over time, your clinicians can use it to be guided in all future decisions about your drug therapy. Any database which stores genetic data must naturally offer secure data storage.

Can my pharmacogenetic test results be used against me in some way?

The legal situation varies between countries. Generally, it is against the law for health insurers to request genetic information to make decisions on premiums or coverage, although this may not apply to life insurance.

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