Rare Classroom: CASQ2-Related Catecholaminergic Polymorphic Ventricular Tachycardia

Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The rare disease that we will be learning about today is:

CASQ2-Related Catecholaminergic Polymorphic Ventricular Tachycardia

Well that’s a mouthful, let’s go with CASQ2 CPVT for short.

What is CASQ2 CPVT?

  • This disease is a form of tachycardia (a heart rate that is higher than normal and irregular)
  • Potentially fatal
  • Symptoms triggered by strong emotions or physical exercise
  • CPVT of all types estimated to affect 1 in 10,000 people (about 32,300 estimated patients in US)
  • Cardiac events occur in over 50 percent of patients
  • No structural abnormalities

How Do You Get It?

  • CASQ2 CPVT is linked to mutations affecting the CASQ2 gene
  • The mutation must be inherited from both parents

What Are The Symptoms?

  • Some patients don’t experience symptoms
  • Seizures
  • Syncope (sudden blackouts or loss of consciousness)
  • Cardiac arrest, which is often fatal
    • In some patients, this is their only symptom of the disease
  • Mortality rate of 31 percent at age 30 without treatment
    • 13 percent with treatment

How Is It Treated?

  • Goal: Reduce cardiac events and prevent death
  • Treatment is ongoing for life. Additionally, genetic testing is recommended for all 1st degree relatives
  • Barriers to treatment include diagnosis either after a cardiac episode or through genetic testing and awareness of condition
  • Avoid strenuous sports and high intensity physical exertion
  • Beta blockers
    • Nadolol is the blocker of choice for long lasting effects to prevent cardiac arrest
    • Highest tolerated dose should be used
  • Flecianide
    • For patients that do not respond to beta blockers
    • Can be used in combination with beta blockers
  • Implantable cardioverter defibrillator
    • May be necessary for patients that cannot use beta blockers or don’t respond to them
    • Always used alongside medication
  • Left cardiac sympathetic denervation
    • Last resort option for patients that do not respond to other treatments
    • Carries significant risks and side effects

Where Can I Learn More???

  • Check out our cornerstone on this disease here.
  • You can also learn more about CASQ2 CPVT from the SADS Foundation.

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