Related Experiment Video

Updated: May 8, 2026

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes
11:33

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

Published on: March 12, 2013

Clinical phenotype and functional characterization of CASQ2 mutations associated with catecholaminergic polymorphic

Marina Raffaele di Barletta1, Serge Viatchenko-Karpinski, Alessandra Nori

  • 1Molecular Cardiology, IRCCS Fondazione Maugeri, University of Pavia, Via Ferrata 8 27100, Pavia, Italy.

Circulation
|August 16, 2006
PubMed
Abstract

Insights

Two new mutations in the cardiac calsequestrin gene (CASQ2) were identified in children with catecholaminergic polymorphic ventricular tachycardia (CPVT). These mutations disrupt intracellular calcium regulation, leading to dangerous heart rhythms.

Area of Science:

  • Cardiovascular Genetics
  • Molecular Cardiology
  • Arrhythmogenesis

Background:

  • Four mutations in the human cardiac calsequestrin gene (CASQ2) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT).
  • Understanding the mechanisms of CPVT caused by CASQ2 mutations is limited due to insufficient in vitro characterization of identified mutants.

Purpose of the Study:

  • To identify and characterize novel CASQ2 mutations associated with CPVT.
  • To investigate the functional consequences of these mutations on cardiac myocyte calcium handling and arrhythmogenesis.

Main Methods:

  • Genetic sequencing to identify CASQ2 mutations in CPVT patients.
  • In vitro characterization of CASQ2 mutant protein function, including calcium binding.
  • Expression of mutant CASQ2 in rat myocytes to assess sarcoplasmic reticulum calcium storage and calcium transients.
  • Electrophysiological studies to evaluate the impact of mutations on arrhythmogenic events.

Main Results:

  • A homozygous 16-bp deletion (CASQ2(G112+5X)) and a compound heterozygous mutation (CASQ2(L167H)) were identified in CPVT patients.
  • CASQ2(G112+5X) exhibited impaired calcium binding, while both mutants reduced sarcoplasmic reticulum calcium capacity in myocytes.
  • Myocytes expressing mutants showed reduced I(Ca)-induced Ca2+ transients and spontaneous Ca2+ sparks; isoproterenol induced delayed afterdepolarizations in CASQ2(G112+5X) expressing myocytes.

Conclusions:

  • The identified CASQ2(L167H) and CASQ2(G112+5X) mutations impair cardiac myocyte function by altering calcium regulation.
  • These distinct abnormalities in intracellular calcium handling contribute to the development of tachyarrhythmias in CPVT patients.
  • The study elucidates the molecular mechanisms underlying CPVT associated with novel CASQ2 mutations.

More Related Videos

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation07:15

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Published on: January 16, 2019

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia09:36

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia

Published on: December 22, 2023

Related Concept Videos

Mechanism of Cardiac Arrhythmias01:28

Mechanism of Cardiac Arrhythmias

Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
Dysrhythmias II: Classification of Tachyarrhythmias01:28

Dysrhythmias II: Classification of Tachyarrhythmias

Tachyarrhythmias are a type of dysrhythmia where the heart rate exceeds 100 beats per minute. Here are some common types of tachyarrhythmias:Sinus TachycardiaSinus tachycardia originates from increased impulses from the sinus node, leading to an elevated heart rate. It is often triggered by stress, fever, or exercise.Patients may experience palpitations, a sensation of a racing heart, dizziness, and chest discomfort.Causes and Risk Factors: Common causes include physical exertion, emotional...
Cardiomyopathy I: Introduction and Classification01:25

Cardiomyopathy I: Introduction and Classification

Cardiomyopathy, or CMP, is a group of diseases affecting the myocardial structure, impairing its ability to pump blood effectively. This condition can lead to arrhythmias, heart failure, or sudden cardiac death.Cardiomyopathies are classified into primary and secondary categories:Primary Cardiomyopathy refers to conditions involving only the heart muscle that are often idiopathic (of unknown cause) or genetic. They primarily affect the myocardium without the involvement of other systemic...
Cardiomyopathy II: Dilated Cardiomyopathy01:30

Cardiomyopathy II: Dilated Cardiomyopathy

Dilated cardiomyopathy, or DCM, is a progressive myocardial disorder characterized by ventricular chamber dilation and contractile dysfunction.EtiologyVarious factors can cause DCM, including hypertension and heavy alcohol intake, which contribute to the weakening and enlargement of the heart muscle. Viral infections, such as Coxsackievirus B, adenoviruses, and influenza, can lead to DCM by causing inflammation and damage to heart tissue. Certain chemotherapeutic agents, including daunorubicin,...
Cardiomyopathy III: Hypertrophic Cardiomyopathy01:29

Cardiomyopathy III: Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...