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Calmodulin mutations associated with recurrent cardiac arrest in infants
Lia Crotti1, Christopher N Johnson, Elisabeth Graf
1Section of Cardiology, Department of Molecular Medicine, University of Pavia, Pavia, Italy.
Circulation
|February 8, 2013
Summary
Mutations in calmodulin genes (CALM1, CALM2) cause life-threatening infant cardiac arrest and arrhythmias. These genetic defects impair calcium binding, disrupting heart rhythm regulation.
Area of Science:
- Genetics
- Cardiology
- Molecular Biology
Background:
- Infantile cardiac arrest can lead to sudden, tragic death.
- Genetic causes for these life-threatening heart rhythm disorders are often unknown.
Purpose of the Study:
- To identify the genetic cause of recurrent cardiac arrest in two unrelated infants.
- To investigate the functional consequences of identified mutations.
Main Methods:
- Exome sequencing was performed on two infant-parent trios.
- Candidate gene screening was conducted on an additional cohort of congenital long-QT syndrome patients.
- Biochemical studies analyzed the impact of mutations on calmodulin's calcium binding.
Main Results:
- Three heterozygous de novo mutations in CALM1 or CALM2 were identified in infants with recurrent cardiac arrest.
- Mutation carriers presented with life-threatening ventricular arrhythmias, epilepsy, and delayed neurodevelopment.
- Mutant calmodulins showed significantly reduced calcium binding affinity.
Conclusions:
- Mutations in human calmodulin disrupt calcium binding, leading to a severe infantile condition.
- Calmodulin dysfunction impacts calcium signaling in the heart, causing deadly arrhythmias.
- This identifies a novel genetic mechanism for sudden infant death syndrome.
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