Overall, our work highlights that Gnb5−/− mice not only recapitulate IDDCA’s neurological manifestations previously outlined elsewhere22 but also mimic its cardiac perturbations, especially regarding heart arrhythmias and autonomic nervous system control, allowing for future screening of drugs modulating the parasympathetic branch of the autonomic nervous system, in view of the development of patients’ therapy. This evidence concerns the gene GNB5 and cardiac arrhythmia.