We demonstrated that the affinity for Cav1.2‐NSCaTE is still significantly decreased for the arrhythmia‐associated variant Q135P, from 2.2 ± 0.2 μM (CaM‐WT) to 12.3 ± 0.4 μM (CaM‐Q135P). Here, CACNA1C is linked to cardiac arrhythmia.