Patient-derived cells demonstrate that mutated RyR2 calcium leak underlies autism spectrum disorder and inherited arrhythmias

Catecholaminergic polymorphic ventricular tachycardia (CPVT) and autism spectrum disorder (ASD) are increasingly recognized as comorbid conditions, yet their shared molecular mechanisms remain unclear. This study investigates a novel RyR2-R169P mutation identified in a patient diagnosed with both CPVT and ASD, hypothesizing that this mutation drives calcium (Ca2+) dysregulation in cardiac and neuronal cells. Using patient-derived induced pluripotent stem cells, we generated ventricular-like cardiomyocytes and midbrain neurons. In cardiomyocytes, the RyR2-R169P mutation increased diastolic Ca2+ leak, elevated single-channel open probability, and induced arrhythmogenic Ca2+ waves under {beta}-adrenergic stress. Similarly, neurons exhibited abnormal cytosolic Ca2+ levels, enlarged soma size, and a clear trend to disrupted neurotransmitter release, including reduced GABA and elevated L-DOPA and serotonin. RyR2 biochemical analysis showed reduced phosphorylation of RyR2 by CaMKII, increased PKA dependent phosphorylation and dissociation of calstabin2 in neurons. Pharmacological stabilization of RyR2 with S107 normalized Ca2+ handling in both cell types, restored neuronal morphology, and prevented calstabin2 depletion and CaMKII phosphorylation increase. S107 restores normal neurotransmitter release only when treatment starts before neuronal differentiation. Structural modeling revealed that the R169P mutation destabilizes the N-terminal domain of RyR2, priming the channel for pathological Ca2+ leak. These findings establish RyR2-R169P as a dual regulator of Ca2+ homeostasis, directly linking cardiac arrhythmogenesis to neurodevelopmental deficits. Our results highlight RyR2 dysfunction as a shared mechanism in CPVT-ASD comorbidity and propose Rycals as a promising therapeutic candidate for mitigating Ca2+-driven pathologies in both tissues. This work demonstrates the importance of RyR2 functional integrity in neurodevelopmental processes. One Sentence SummaryNovel RyR2-R169P mutation causes calcium leak in hiPSC-derived cardiomyocytes and neurons, linking CPVT to autism via RyR2 dysfunction.