In cardiac hypertrophy (CH), whether observed in a spontaneously hypertensive rat model or induced in vitro by angiotensin II (Ang II) on cardiomyocytes, there is a downregulation of GJA1-20k expression mediated by Jak2 signaling, associated with reduced gap junction presence at the ICDs [45]. The gene discussed is GJA1; the disease is cardiac hypertrophy.