Is Restrictive Cardiomyopathy Hereditary

​With all the interest in genetic testing these days, you may be wondering if restrictive cardiomyopathy is hereditary.

If so, should you get genetic testing for yourself and/or your family?

And what exactly is restrictive cardiomyopathy? Should you be concerned about it?



What is Restrictive Cardiomyopathy?

restrictive cardiomyopathy

Restrictive cardiomyopathy is in a group of cardiac disorders known as “infiltrative cardiomyopathy.” This specific form of heart disease is a coronary condition where the ventricles of the heart become stiff. A heart ventricle is one of two lower chambers in the heart that pump blood throughout the body.

When the walls of the one or both of the ventricles become hardened and stiff, the heart as a pump cannot do its job as well. The ventricles cannot achieve their full relaxation can end up with too much blood. This can cause the atria (the two upper chambers of the heart) to become enlarged.

The end result is that the blood flow in the heart is decreased. This could lead to irregular heart rhythms (arrythmias) that can increase the risk of blood clots. You could also have a heart attack or heart failure if the condition becomes very pronounced.



Causes of Restrictive cardiomyopathy

Restrictive cardiomyopathy can be hereditary (genetic) or it can be caused by a disease or disorder, as well as certain types of cancer treatments. Here are some of the causes of restrictive cardiomyopathy:

  • Genetic predisposition
  • Hemochromatosis (too much iron in the blood)
  • Sarcoidosis (a typical diagnosis from TV’s House, this is an inflammatory disease)
  • Amyloidosis (abnormal protein build-up)
  • Connective tissue disorders
  • Radiation and chemotherapy (used in cancer treatments)

If a specific cause cannot be found, then the disease might be labeled “idiopathic restrictive cardiomyopathy.” “Idiopathic” means they don’t know exactly why a disease condition has occurred.



The Genetic Condition: Familial Restrictive Cardiomyopathy

When restrictive cardiomyopathy is due to genetics, it is called “familial restrictive cardiomyopathy.” The term familial, of course, refers to “family.”

The condition is the pretty much the same as restrictive cardiomyopathy, because it is caused by a stiffened heart muscle. In familial restrictive cardiomyopathy, the stiffness is caused by mutations in certain genes.

The main gene involved in familial restrictive cardiomyopathy is TNNI3. The purpose of these gene is to deliver instructions to a heart protein known as cardiac troponin I. This protein regulates the heart muscle’s alternating periods of contraction and relaxation.

When this TNNI3 gene mutates, the cardiac troponin I protein produced can be defective. This means the heart cannot fully relax, which reduces blood flow to the ventricles (the lower chambers of the heart). This then means more blood is built up in the atria, or upper heart chambers. Once again, this can cause heart rhythm irregularities and heart failure.

Sometimes, mutated genes other than TNNI3 are involved in a small percentage of genetic cases. Other genes associated with familial restrictive cardiomyopathy include ACTC1, MYH7, and TNNT2.

In some families, a hereditary link may be there, but no gene association has been found. Regardless of the gene involved, the end result is the same.



When Can Familial Restrictive Cardiomyopathy Show Up?

Familial restrictive cardiomyopathy can manifest in people of all ages, from childhood to adulthood.

Unfortunately, many families do not realize they have the genetic predisposition for familial restrictive cardiomyopathy. Sometimes children may show no signs or symptoms of the illness whatsoever, but then die of heart failure without warning.

This is a very upsetting, tragic occurrence that would be devastating to any family. To see a child cut down just as life is beginning is truly heartbreaking. For this reason, if this problem runs in the family, then having your children examined by a competent cardiologist could be life-saving.

For adults who have the condition, if it is left untreated, the condition will kill approximately one out of three within five years of initial diagnosis. This is why treatment is very important, not just for children, but for adults as well.



What Are the Symptoms of Restrictive Cardiomyopathy?

restrictive cardiomyopathy

Restrictive cardiomyopathy has many common symptoms, regardless as to whether it is inherited or not. These signs and symptoms can include:

Children who have familial restrictive cardiomyopathy may have a hard time putting on weight or may be small for their age. In addition, they may have some of the symptoms listed above.



How is Restrictive Cardiomyopathy Treated?

Treating restrictive cardiomyopathy can be challenging, but the disease can be helped by lifestyle changes and medicines, including beta blockers and ACE inhibitors. Make sure you eat a heart healthy diet with lots of vegetables, fewer processed foods, and less red meat. Exercise regularly in accordance with your doctor’s instructions and build up your strength by starting out slow with frequent breaks.

Stress reduction is important in any sort of heart condition. Learning mindfulness meditation may be one way to keep stress at bay.



Should You Get DNA Testing to See if You or Your Family Is at Risk?

Given the chance that a child might die if they have undiagnosed familial restrictive cardiomyopathy, you might be tempted to run out right now and buy a DNA testing kit.

The thing is, if you do not have a family history of heart disease, especially familial restrictive cardiomyopathy, you may not need to be tested for this. You should talk to your doctor first about it.

However, if you do have a family history of heart disease and restrictive cardiomyopathy, then DNA testing might be a good idea.



Commercial Genetic Testing for the Public

You can find many places online that will offer DNA testing for health issues. Sometimes, they will even bundle in ancestry information with your health report.

The question is, will they test for specific markers that relate to familial restrictive cardiomyopathy? Sometimes, these for-profit DNA testing outfits will provide you with a general health report that covers common problems such as a predisposition to Alzheimer’s disease.

These online testing companies may or may not be able to detect mutations in TNNI3 or related genes.

Sometimes, the DNA testing company will report on the most common diseases but give you raw results on your DNA that you can then send to another website or lab to be interpreted. This may or may not cost you additional money.

Before spending money on a commercial DNA test that might give you results that are too genetic, talk to your doctor. You can also email or call the customer support service of that DNA testing company to see if they offer genetic testing on anything related to familial restrictive cardiomyopathy.

Remember: Any commercial DNA test that you get done will be out of pocket. You will not be reimbursed by your health insurance for this type of testing.



Medical Genetic Testing by Your Doctor

MEDICAL GENETIC TESTING BY YOUR DOCTOR

In addition, your doctor may order a specific genetic test for this condition, such as the GeneSeq®: Cardio Familial Cardiomyopathy Profile.

According to the website, this test can:

• Confirm a diagnosis of familial cardiomyopathy.

• Identify which subtype of a particular cardiomyopathy.

• Identify family members of an index patient who harbor the familial mutation and may wish to undergo cardiac screening at regular intervals.

• Facilitate appropriate genetic counseling for family members.

This test is not something the general public can order directly. Only a health provider can order this specific test. It is possible, but not a given, that your health insurance might cover the cost of this test.



Remember: A Predisposition Is Not Destiny!

It can be really scary to get a DNA report back with some “bad news” on it. Some people have taken drastic measure based on DNA results, even though they do not have any symptoms of a disease. Women getting full double mastectomies out of fear of getting breast cancer, because they have a genetic predisposition to it, is one major example. (Actress Angelina Jolie is one famous example of this.)

Remember: a genetic predisposition to specific disease is not a guarantee that you will get that disease. Getting some negative information on a DNA report is no reason to panic or freak out. Whether or not a disease manifests has to do with a variety of factors, including diet and lifestyle as well as overall stress, environment, and sometimes just luck.



Restrictive Cardiomyopathy: The Prognosis

Restrictive cardiomyopathy can be a scary disease but with proper management, you or your child may live a long, healthy, and productive life. They key to thriving with restrictive cardiomyopathy whether it is familial or not, is to maintain a healthy lifestyle and get regular checkups with your cardiologist. Make sure you manage your stress and eat well. With some precautions, you may outlive many others without the condition!

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