Life sciencesJul 7, 2026

Gene-edited heart cells modeling short QT syndrome type 3 show electrical differences and varied drug responses

CRISPR Gene Editing Weekly Brief ↗PubMed ↗DOI ↗

Updated Jul 8, 2026

Abstract

An isogenic human induced pluripotent stem cell model was successfully generated to study short QT syndrome type 3.

Short QT syndrome (SQTS) is linked to genetic mutations that cause significant heart rhythm disturbances.
The KCNJ2 mutation associated with SQTS was introduced into a normal human induced pluripotent stem cell line using a precise gene-editing technique.
Differentiation of these edited cells into heart cells confirmed shortened field potential duration (FPD), mirroring the QT interval observed in affected individuals.
Quinidine, a known treatment, effectively prolonged FPD in these heart cells, aligning with previous clinical findings from a limited number of patients.
Chloroquine also prolonged FPD and induced irregular heartbeats, suggesting potential arrhythmogenic effects that require further investigation.

Simplified

Short QT syndrome (SQTS) is a genetically inherited autosomal dominant cardiac channelopathy associated with paroxysmal atrial and ventricular fibrillation, syncope, and sudden cardiac arrest. Although SQTS is a well-known arrhythmogenic disorder, no optimal therapies currently exist due to its rarity and the challenges associated with diagnosis. Rodent models and patient-derived induced pluripotent stem cell (iPSC) models have been used to evaluate potential drug effects, but physiological and genetic variability between species and individuals can limit their fidelity. To address these limitations, we generated an isogenic human iPSC (hiPSC) model by introducing the short QT syndrome type 3 (SQT3)-associated KCNJ2 mutation into a normal hiPSC line using the Prime Editing 7 (PE7) system and differentiating it into cardiomyocytes (CMs). Multi-electrode array (MEA) analysis confirmed shortened field potential duration (FPD), an in vitro correlate of the QT interval as an electrophysiological SQT3 phenotype, validating the model's relevance to SQT3. Quinidine produced a consistent FPD-prolonging effect in the isogenic hiPSC-CMs, recapitulating previous clinical observations in a small number of SQT1 patients and supporting the model's utility as a reliable in vitro surrogate for assessing therapeutic strategies. Additionally, chloroquine, a selected candidate that has not yet been clinically validated, was evaluated and found to prolong FPD and induce irregular spontaneous beats indicative of arrhythmia. Overall, these findings demonstrate the potential of isogenic hiPSC-based platforms for elucidating disease mechanisms in rare genetic arrhythmogenic disorders and advancing the identification of candidate therapeutic agents.

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Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

PubMed

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Gene-edited heart cells modeling short QT syndrome type 3 show electrical differences and varied drug responses

Abstract

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Competing interests

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