Penetrance and expressivity of the R858H CACNA1C variant in a five-generation pedigree segregating an arrhythmogenic channelopathy.

Background: Isolated cardiac arrhythmia due to a variant in CACNA1C is of recent knowledge. Most reports have been of singleton cases or of quite small families, and estimates of penetrance and expressivity have been difficult to obtain. We here describe a large pedigree, from which such estimates have been calculated.