PRKAG2 Cardiac Syndrome
Details
PRKAG2 cardiac syndrome is an autosomal dominant metabolic cardiomyopathy caused by pathogenic variants in PRKAG2, the gene encoding the γ2 regulatory subunit of AMP-activated protein kinase (AMPK). AMPK is a master metabolic sensor; γ2 mutations cause constitutive AMPK activation, leading to pathological glycogen accumulation in cardiomyocytes. The condition is distinct from typical accessory pathway WPW because ablation of the pathway cannot address the progressive underlying metabolic disease.
Key Facts
- Genetics: Autosomal dominant; pathogenic variants in PRKAG2 (γ2-AMPK subunit); rare familial WPW; several families reported worldwide
- Phenotype tetrad: Cardiac hypertrophy + pre-excitation (WPW ECG pattern) + glycogen storage in myocardium + progressive atrioventricular/His-Purkinje conduction disease; eventually requires permanent pacemaker or ICD in many patients (sources/gene-editing-cv-tcm-2025 — medium)
- Mechanism: Constitutive AMPK activation → excessive glucose uptake → intramyocyte glycogen accumulation → myocyte enlargement and vacuolisation → accessory pathway formation/preservation and conduction tissue disruption (sources/gene-editing-cv-tcm-2025)
- Progressive course: Unlike isolated accessory pathway WPW, PRKAG2 syndrome progresses over decades with worsening hypertrophy, increasing conduction disease burden, and recurrent symptomatic arrhythmias not addressed by ablation alone (sources/gene-editing-cv-tcm-2025)
- Ablation limitation: Catheter ablation can eliminate the accessory pathway acutely but cannot address the metabolic substrate; conduction disease progresses regardless, and additional conduction tissue may be recruited over time (sources/gene-editing-cv-tcm-2025)
Gene Editing Evidence
- Xie et al. 2016 (preclinical): CRISPR targeting of PRKAG2 mutations in transgenic and knock-in mouse models reversed cardiac hypertrophy and pathological glycogen storage — proof-of-principle for gene correction (sources/gene-editing-cv-tcm-2025)
- AAV9-CRISPR/Cas9-sgRNA (mouse models): Single postnatal injection restored cardiac function in PRKAG2 transgenic mice (sources/gene-editing-cv-tcm-2025)
- iPSC-CM correction: CRISPR correction of patient-derived iPSC-CMs normalised arrhythmic behaviour compared to uncorrected mutant cells (sources/gene-editing-cv-tcm-2025)
- PRKAG2 syndrome is cited as a paradigm case where gene editing is clinically appropriate over standard ablation — the existing standard of care (ablation) is definitively insufficient for this multisystem monogenic disease (sources/gene-editing-cv-tcm-2025)
Contradictions / Open Questions
- All gene editing evidence is preclinical (murine models and iPSC-CMs); no human clinical trial data exist
- Optimal timing of intervention (pre-hypertrophy vs symptomatic) is unknown
- AAV packaging capacity (4.7–5.1 kb) may constrain CRISPR/Cas9 delivery; split vector strategies are untested in this condition
- Long-term durability and reversibility of correction unknown
Connections
- Related to concepts/Gene-Editing-Risk-Benefit-Framework
- Related to concepts/CRISPR-Cas9-in-Channelopathies
- Related to concepts/AAV-Gene-Delivery
- Related to concepts/iPSC-Derived-Cardiomyocytes