Video Transcript
Warfarin is a drug used to prevent blood clots from forming in the body. Some people have mutations in the enzyme that breaks down warfarin, which leads to dangerous side effects. What is the best way for doctors and scientists to determine who not to give warfarin to? Our answer choices are (A) take a patient’s written consent, (B) sequence the genome and look for the mutation, (C) test them with other drugs first, or (D) give them warfarin and see what happens.
First, let’s examine some of the key details in this question. Warfarin is the name of a drug that’s used to prevent blood clots in some patients. It can also be referred to as a blood thinner. There’s an enzyme in our bodies responsible for breaking down warfarin when it’s taken. People who have a mutation in this enzyme should not take warfarin. When choosing the correct response for this question, it’s helpful to recall the central dogma of biology, which states that DNA or genes are transcribed into RNA and then that RNA is translated into a string of amino acids that are eventually folded into a functional protein.
An enzyme is a type of protein. In order for us to observe a mutation in a protein, there must also be a mutation in the DNA that codes for that protein. So this question is essentially asking us how best to determine who has this mutation to avoid giving them warfarin, which may cause dangerous side effects in these particular patients. Also important to note is that when a question is asking for the best choice, more than one option may seem correct. And we’re responsible for choosing the option that is the most correct. Now, let’s review our answers.
Take a patient’s written consent. While it’s important to gain informed consent before performing risky or experimental procedures on a patient, informed consent will not help us to differentiate between patients who have a mutation in the enzyme that breaks down warfarin and patients who do not.
Sequence the genome and look for the mutation. If a doctor took a sample of the patient’s DNA, they could sequence the gene for the enzyme and figure out who has the mutation. This is a good method for preventing anyone with the mutation in this enzyme from being prescribed warfarin.
Test them with other drugs first. Testing a patient with drugs is not an effective way to figure out if a patient has a mutation or not.
Give them warfarin and see what happens. While you may eventually figure out who has the mutation and who doesn’t this way, the question states that patients with the mutation in their enzyme face dangerous side effects. This answer is not the best choice because it potentially endangers the patient’s lives.
So the best way for doctors to determine who not to give warfarin to is to sequence the genome and look for the mutation.
