The Heart of Genetics

Hi blog dogs! Hope everyone is staying safe from the virus, and hopefully many of you, like me, are getting the added bonus of working from home. My favorite little heart failure dog is a huge fan. I just hope my patients don’t hear him coughing once an hour. They might get concerned.

Poor guy, we love him, coughing fits and all.

So having him around so much has reminded me that I haven’t really written about one of my favorite genetic topics, except as it directly relates to him. Cardiology genetics!

There’s an amazing podcast episode by Eleanor Griffith and Nori Williams which focuses entirely on sudden death cardiac genetics. Nori works in the NY Medical Examiner’s Office and uses genetic testing to rule out or discover genetic causes of sudden unexplained deaths. Her work allows families to get closure on unexplained deaths, and determine if anyone in their family might be at risk of a similar condition. This episode is definitely worth a listen; it really got me interested in cardiogenetics!

But even outside of unique pockets of GC like that, cardiology genetics is a growing field. In 2017, I shadowed a couple of cases in cardiology genetics, as one of my first shadowing experiences. These cases all involved families just generally concerned about a family history of heart disease or a known genetic cardiac condition, and interested to learn their own risk. In through those appointments, I learned that genetic mutations can cause heart disease through two central mechanisms; they can affect the structure of the heart or the electrical function. I wanted to briefly cover those two main facets of cardiogenetics, and possibly explore more specific conditions going forward.

Figure 2.
Here’s an outline I found here that is supposed to be a simple diagram of how a genetic mutation can cause cardiomyopathy, or abnormal heart structure. Hope you remember your cell bio. 🙃

Can’t wait to study this in GC school and actually understand that diagram hopefully, lol. But essentially, a typo in a gene can knock out essential functions of the bits of our cells that carry out muscle building and contraction. If anything in this whole complex pathway doesn’t work well, the heart muscle can be misshapen, weak, or unusable. Such a condition can support life for some time (my doggo is living proof of that), but often early death is expected ( ☹️).

And then check this out:

Figure 1.
Calcium, Sodium, and Potassium channels, baby! Come throughhhhhhh Advanced Physiology knowledge.

These diagrams, from the same academic paper cited above, show several of the channels that transfer key ions into and out of cells. Cells rely on these channels to keep electrical balance, and to shift that electrical balance to respond to stimuli. Actually, pain relief, sedative, and aid in dying drugs, all work by intervening in these channels, preventing certain electrical charges from causing a systemic reaction (such as the sensation of pain).

As demonstrated, these channels in our cells can affect our bodies on a systemic scale.The body depends on this current of electricity, especially our cardiac function. In people with genetic mutations affecting these pathways, the electrical activity of the heart can become disrupted. I find these conditions particularly interesting, and a bit scary, as a healthy person can live with an abnormal cardiac electrical pattern with no symptoms, and then suddenly die. Nori and Eleanor discuss a case like that in their podcast episode.

*wonders if I have to learn to read EKGs in grad school*

Now that we have a bit of an idea of the science of cardiogenetics, and why these issues can lead to untimely death, we can consider what it would be like to counsel a family experiencing these conditions, or fearing them. I can’t even imagine what it would feel like to have a family history of sudden and unexplained deaths, or young deaths due to cardiac conditions. I’m sure that leads to fear, guilt, anxiety, and grief. These conditions could be some of the most challenging to counsel for, and especially to divulge positive genetic testing results for.

There are medications that can help prevent severe cardiac events, but there are no easy fixes for the conditions themselves. A person with a cardiac genetic mutation will remain at higher than average risk for heart-related death. I feel a great role genetic counselors have in this situation is listening. Allowing patients to vocalize their fears and thereby gain some semblance of control over them. As in all counseling, a listening ear and the chance to unload are truly priceless to a person experiencing fear and grief. It’s the best a GC can offer, and often all they can offer in the face of these challenging conditions. But it is enough to fulfill their most important role as a counselor and advocate.

I liked covering this lesser-known avenue of GC. Maybe next week we can talk about infertility genetics, something that has been near and dear to me this past year as we attempted to try for baby and very much failed. (We’ve now stepped back from fertility treatments for a while to focus on hopefully going to grad school!) Probably not genetics-related in our case but I feel for our friends in the infertility world who do fall into this category.

Image result for negative pregnancy test
Stock photo, but also very much me.

Keep strong through quarantine and GC interview season. Wash your hands, stay away from the elderly, and don’t panic. You have plenty of toilet paper.

-Laura Cooper-Hastings

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