CACNA1B and cardiac arrhythmia: For instance, a CACNA1B missense variant (c.4166G > A; p.Arg1389His) was reported in a family with adult-onset myoclonus-dystonia and cardiac arrhythmia, which resulted in lower current Cav2.2 channels, emphasizing the functional relevance of this paralog (Groen et al. 2015).