q80k Polymorphism

What is q80k Polymorphism?

When a person has a virus, such as hepatitis C, the virus has its own DNA. When a virus is being treated with medication, sometimes a virus is able to alter their DNA to avoid being killed by the medication, a description of an action that is called polymorphism. This is what happens when a virus is referred to as “drug resistant.”  In the case of hepatitis C, the specific type of DNA alteration or polymorphism that the virus can do is called q80k.

What does q80k Polymorphism have to do with hepatitis C?

When a person gets tested for hepatitis C, they go through a series of three tests; first is to find out whether the person has been exposed to the hepatitis C virus. If the test is positive, the next test is to find out whether the person has been infected with the hepatitis C virus. If that test is positive, the final test is to discover the specific kind of the virus (called its genotype) that the person has. There are currently six known genotypes (types 1-6), and there are subtypes within these genotypes. For example, a person may be told they have hepatitis C 1a. That means that the person has tested positive for hepatitis C, with the genotype 1, with the subtype a.

This is important to know because most drugs to treat or cure hepatitis C are based on the specific genotype of the virus. This means that a person with genotype 1 will likely be prescribed a different medication than a person with genotype 6. To better understand this, think of the children’s toy that has block shapes and a board with shaped holes in it. The goal is for the child to put the star shaped block into the star shaped hole, for the triangle shaped block to go into the triangle shaped hole, and so on. All of the shapes are blocks, just as all of the genotypes are hepatitis C. However, each shape is different and fits into a different hole, just as each of the genotypes are different and require a different medication.

Before medical advancements, there was one drug, intended to treat everyone with hepatitis C. Using our example, this would be like having one giant hole in the board that all of the shaped blocks fit through. Although it provided some success, it was certainly less beneficial and less specific than in present day, when doctors can find out the exact genotype of the patient’s virus. However, viruses are tricky. They do not want to be killed by the medication. As an attempt to avoid this, some viruses morph into slightly different versions of their original selves, called polymorphism. Returning to our example, it would be as if the circle shaped block did not want to go through the round hole, so it turned itself into an oval or a triangle. In some cases, the polymorphism is small and insignificant enough that the medication still works (such as if the block went from being perfectly circular to being slightly oval shaped). In other cases, the change is significant enough that the medication stops working and a new medication needs to be used to rid the patient’s body from the morphed version of the virus (such as if the round block became a triangle shape).

The most common experiences of q80k polymorphism is in the hepatitis C genotype 1, subtype a. Approximately 40% of all hepatitis C infections are genotype 1 and approximately 75% of all genotype 1 strains are subtype a.

How can I avoid q80k Polymorphism?

This is not something you can avoid or alter within yourself. It is simply the way some patients’ virus replicates within their bodies and the way some viruses try to combat the effects of the antiviral drugs that are being taken to rid the body of the hepatitis C virus.

How do I know if I have q80k Polymorphism?

It is typically recommended that patients with hepatitis C genotype 1, subgroup a, be tested shortly after beginning hepatitis C treatment. This is because q80k polymorphism is a known concern for this group of people. If you have this specific type of hepatitis C, your doctor may schedule a blood test soon after you begin taking your antiviral medication. In other cases, your doctor may wait to provide this test. This often happens if the patient is unable to afford many tests (which often happens when insurance does not automatically cover the costs of this test or if the patient is paying for all treatment privately). In such cases, the doctor may have the patient take extra notes on their symptoms for future review or the doctor may give the patient a list of symptoms and request to be contacted if the patient experiences any of them, as these could be signs that the prescribed antiviral drug is not working, which could then be a sign that the virus has morphed.

What happens if I get q80k Polymorphism?

This isn’t something that you get, it is simply something that some people experience. You may be tested for this before ever experiencing any sign of ineffective medication or you may have some symptoms that lead you to be tested. In either case, your physician will obtain the necessary information through testing to decide whether the polymorphism is severe enough to warrant alterations to your medical regimen. If so, the doctor will prescribe a new medication to be taken instead of or in addition to your previous prescription. Be sure to ask any questions you may have so that you understand which medication to take and when. If you are concerned with your current medication, if you think you are experiencing q80k polymorphism, or if you have questions about your medication schedule, please contact your doctor.1-6

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