MYBPC3 and cutaneous mastocytosis: Importantly, the penetrance of variants found in individuals with CM and relatives in a clinical setting is increased compared to the penetrance of variants estimated for those identified through SFs (e.g., MYBPC3 c.1504C>T [p.Arg502Trp] [GenBank: NM_000256.3] with estimated penetrance of 50% in individuals with HCM and 6% here in the population).