Table 2. Maximum credible population frequencies and maximum tolerated ExAC allele counts for variants causative of exemplar inherited cardiac conditions, assuming a penetrance of 0.5 throughout.

Disease	Maximum allelic contribution	Prevalence	Penetrance	Maximum population frequency	Maximum tolerated ExAC allele count
Marfan	0.015	1/3,000	0.5	5.0 × 10−6	2
Noonan	0.10	1/1,000	0.5	1.0 × 10−4	18
CPVT	0.10	1/10,000	0.5	1.0 × 10−5	3
Classic Ehlers-Danlos	0.40	1/20,000	0.5	2.0 × 10−5	5

CPVT,catecholaminergic polymorphic ventricular tachycardia; ExAC, Exome Aggregation Consortium database.

Prevalence estimates (taken as the highest value reported) were obtained from Marfan,⁴⁰ Noonan,¹⁸ CPVT,¹⁹ and classical Ehlers-Danlos.²⁰