What We Learned About Izzy’s Heart

To understand what happened to Izzy, it helps to understand how the heart works. Your heart is a muscle, but it runs on electricity. Every single heartbeat is triggered by a tiny electrical signal, almost like a spark plug in a car engine.

We all have a specific gene in our DNA called SCN5A. You can think of this gene as the instruction manual that tells the body how to build those spark plugs. When the manual is written perfectly, the electrical signals fire correctly, and the heart stays in a steady, normal rhythm.

Izzy’s DNA Result

After Izzy passed away, doctors looked very closely at her DNA and found a variation in her SCN5A instruction manual. Her official result was c.1109 C>T p.(T370M).

While that looks like a complicated math equation, it actually just describes a tiny spelling mistake:

• The Typo (c.1109 C>T): DNA is written using just four letters (A, C, T, and G). In Izzy’s manual, exactly at position number 1,109, a letter “C” was accidentally swapped for a letter “T”.
• The Result p.(T370M): Because of that single swapped letter, her body used a slightly different ingredient when building her heart’s electrical system.

Where Izzy Fits on the Chart

If you look at the chart on this page, you can see that a lot of people have harmless spelling changes in this gene. But Izzy’s specific variation is extremely rare. It falls deep into the tiny “<1% All Others” category.

More specifically, genetics labs classify her result as a Variant of Uncertain Significance (VUS). One of over 2,000 other variations in the same classification. This means the spelling mistake is so incredibly rare that scientists simply haven’t seen it in enough people to prove exactly what it does. Science is still trying to catch up to her genetics.

What Happened

Because her variation is a VUS, doctors cannot say with 100% certainty that it caused her heart to stop. However, because Izzy was such a strong, perfectly healthy athlete, this hidden genetic mystery is the biggest clue we have.

Doctors highly suspect that this tiny, invisible flaw in her DNA made her heart vulnerable to suddenly losing its electrical rhythm without any warning. It wasn’t caused by anything she did. Learning about this helps us understand the science behind what happened, and reminds us that the human heart is incredibly complex, and there are still mysteries in genetics that doctors are working hard to solve.

The Heart’s Reset Button: Understanding Long QT

When we look at variations in the SCN5A gene, one of the main conditions doctors look for is called Long QT Syndrome.

To understand what Long QT is, think about a camera flash. After you take a picture, the flash needs a second to recharge before you can take another one. Your heart works the exact same way. Every single time it beats, its electrical system has to instantly reset itself so it is ready for the next beat.

In a perfectly normal heart, this recharge happens in a fraction of a second. But for someone with Long QT Syndrome, the heart takes just a tiny bit too long to reset.

The SCN5A Connection

Remember how the SCN5A gene is the instruction manual for the heart’s electrical “spark plugs”? When there is a rare typo in that manual, those spark plugs can get a little bit sticky. They stay open a millisecond longer than they are supposed to. This extra delay is what causes the heart to take too long to recharge.

Most of the time, a person with Long QT won’t even feel this happening. Their heart keeps beating, just with a slightly slower reset in the background.

The Triggers: The Perfect Storm

So, if the heart is still beating, why is it dangerous?

The danger happens when a “trigger” occurs at the exact wrong millisecond. Imagine playing a video game where your character is frozen while their energy shield recharges. If an enemy strikes exactly while you are frozen, it causes a glitch.

In the heart, if a specific trigger happens right while the electrical system is struggling to recharge, the signals collide and trip over each other. The heart suddenly forgets how to beat in a steady rhythm and starts quivering fast and out of control. This is called an arrhythmia, and it stops the heart from pumping blood to the body.

What Causes the Trigger?

There are a few different types of Long QT. For some types, the trigger is heavy exercise. But for the specific type caused by the SCN5A gene (called Type 3), the triggers are often the exact opposite.

For people with an SCN5A variation, the electrical glitch is actually most likely to happen when the heart is beating slowly and the body is completely relaxed. The most common triggers are deep sleep or resting.

This is one of the hardest things to understand, but it explains why someone can be a fierce, incredibly strong athlete on the softball field, but still have a hidden vulnerability when their body is simply at rest. It is a completely invisible condition, waiting for a perfect storm.

The Microscopic Gates: What is a Sodium Channel?

To understand what Izzy’s genetic variation actually did, we have to zoom in close to a single heart cell and look at something called a sodium channel.

How the Heart Makes Electricity

Imagine a massive football stadium with thousands of closed doors. Outside those doors, millions of fans are waiting to get in. If you suddenly throw all the doors open at exactly the same time, the fans will rush inside all at once. That sudden, massive rush of movement creates a huge wave of energy.

Your heart cells work exactly the same way.

• The Doors: The “doors” on the outside of a heart cell are called sodium channels. They are microscopic gates that open and close.
• The Fans: The “fans” waiting outside are tiny particles of sodium (salt) that naturally float in your body.

When your brain tells your heart to beat, all of those sodium channels fly open. The sodium particles rush inside the cell. That sudden chemical rush is literally what creates the electrical spark that makes the heart muscle squeeze.

How the Code Changed the Gate

This is where the SCN5A gene comes in. That gene is the instruction manual the body uses to build those microscopic doors.

Because Izzy had a tiny typo in her code, her body used a slightly different ingredient to build the hinges on her heart’s doors. They still worked, and they still let the sodium in to start the heartbeat perfectly. But because the hinge was different, the doors were “sticky.”

The Sticky Door

Instead of slamming shut the millisecond the heartbeat started, Izzy’s doors lingered open just a fraction of a second too long. Because the doors didn’t close fast enough, a little bit of extra sodium leaked into the cell.

That extra sodium is what caused the Long QT delay we talked about earlier. The cell had to work overtime to pump that extra sodium back out before it could recharge and be ready for the next beat. It was just a microscopic sticky door, but it was enough to make the heart vulnerable to losing its rhythm.

The Challenge of a “Maybe”: Why Knowing Wouldn’t Have Changed Things

It is really natural to ask a painful question: If this spelling mistake was always in Izzy’s DNA, why didn’t doctors catch it and fix it before it was too late?

The heartbreaking truth is that even if doctors had run a massive genetic test and found this exact typo years ago, it wouldn’t have triggered any medical action. Here is why.

The Split Decision

When a genetics lab finds a typo in someone’s DNA, they have to decide if it is dangerous or harmless. But for Izzy’s specific variation—c.1109 C>T—the world’s top scientists actually disagree.

If you look up her variation in the giant databases that genetics labs use, the results are split:

• Some labs look at it and say, “We think this might cause a heart problem.”
• Other labs look at the exact same typo and say, “We think this is just a harmless difference, like having blue eyes.”

Because the science world is split, this variation is officially stuck in that “Variant of Uncertain Significance” (VUS) category we talked about earlier. To doctors, a VUS basically means “Maybe.”

Doctors Can’t Treat a “Maybe”

When a teenager is an incredibly strong, active athlete who feels perfectly fine and has no symptoms, doctors cannot perform major medical procedures based on a “maybe.”

Treating a serious heart condition usually means installing a device like a defibrillator inside the chest or putting a person on heavy medications that change how their body works. Doctors will only do these things if a DNA variation is 100% proven to be dangerous (Pathogenic). They will never do heart surgery or tell a healthy kid to stop playing the sports they love just because a lab says, “We aren’t sure yet.”

The Edge of Science

If Izzy’s doctors had seen her DNA test a year ago, they would have looked at her healthy, athletic life, looked at the “Uncertain” lab results, and told her to just keep playing softball.

There were no missed warning signs. No doctor made a mistake. Izzy’s heart condition was simply hiding in a blind spot of modern science. While it is incredibly hard to accept, it means there is absolutely nothing Izzy, her family, or her doctors could have done differently. Her heart was just a mystery that science is still working to solve.

Testing the Code: The Lab Study on Izzy’s Variant

Earlier, we talked about how Izzy’s DNA result was officially considered a “Variant of Uncertain Significance” (a “maybe”). But to get closer to the truth, a team of medical scientists actually ran a special laboratory test on her exact genetic typo. This is called a functional study.

Rebuilding the Door in a Lab

Instead of just reading the DNA code on a computer screen, scientists used Izzy’s exact spelling mistake—the c.1109 C>T typo—to build a real, microscopic sodium channel inside a single cell in a laboratory.

Once the cell was built, they hooked it up to microscopic sensors and shocked it with a tiny amount of electricity to watch exactly how the “door” behaved in real life.

The Results: A “Gain of Function”

When the scientists tested this specific door, they found exactly what they were looking for. The official scientific report states that her variation caused a “deleterious gain of function.”

While “gain of function” sounds like a good thing—like gaining a new superpower—in biology, it actually means the door was overactive. It did its job too much.

• A normal door opens, lets the sodium in, and slams shut immediately.
• This specific door opened perfectly, but it “gained” the ability to stay open longer than it should have.

The lab proved that Izzy’s variation directly created the “sticky door” we talked about earlier, allowing extra sodium to leak into the cell and delaying the heart’s electrical reset.

Moving from “Maybe” to “Likely”

Because the scientists could literally watch the door staying open and leaking sodium in the lab, they proved that this specific typo was not just a harmless change like having blue eyes. It was causing a real electrical glitch.

Because of the results of this study, scientists recommended moving Izzy’s specific variation out of the “Uncertain” category and upgrading it into the “Likely Pathogenic” category.

Even though this spelling mistake is incredibly rare, this lab test gave us the hard proof needed to understand exactly why Izzy’s heart lost its rhythm. It points to the possibility that her hidden genetic typo was the missing puzzle piece.

Looking Ahead: Our Family’s Next Steps

Because there is a possibility that Izzy’s heart condition was caused by a tiny spelling mistake in her DNA, it brings up an important question for our family. DNA is genetic, which means it is passed down from parents to children.

Because of this, it is standard medical procedure to check the rest of the family’s DNA, too.

Our Upcoming Appointment

At the end of June, our family—Izzy’s mom, dad, and her sister, Lucy—will be sitting down with a specialized genetics team. We will ask for similar testing to be done on the rest of the family.

Knowledge is Protection

It is natural for people to feel a little anxious when they hear someone has to go to a geneticist or a heart doctor. But for our family, this meeting is actually a very positive, protective step.

If the doctors don’t find the typo in our DNA, it gives us peace of mind. But even if they do find the same hidden variation in one of us, it is still good news that we found it. Because we know exactly what we are looking for now, doctors will know exactly how to monitor it and keep us completely safe.

We are sharing this process because we believe knowledge is power. By learning about our genetics and working with these doctors, we are protecting our family, helping science understand this rare variation, and continuing to honor Izzy.