Genetics, insurance and hypertrophic cardiomyopathy

We specify a mathematical model of Hypertrophic Cardiomyopathy (HCM) and consider the potential costs arising from adverse selection in a life insurance market. HCM is a dominantly inherited heart disorder which is relatively common and has high mortality; a population prevalence of 0.2% and annual mortality hazard (force of mortality) of 1% have been widely cited. Adverse selection may arise if insurers may not take account of adverse DNA-based genetic tests for a causative mutation. A novel feature of our model is that it includes cascade genetic testing (CGT) in nuclear families. CGT is the form of testing used in HCM. Among other things, it implies that genetic testing occurs only if a family history exists. We find in most scenarios the premium increases necessitated by adverse selection to be very small – fractions of 1% – but we ask under what circumstances these might increase to appreciable levels. Insurers' inability to use family history in underwriting would have a large impact. We note that the epidemiology of HCM is still evolving and that 0.2% is likely to be a considerable underestimate of mutation prevalence, while recent estimates of annual mortality hazards are much less than 1%. The first of these in particular is likely to limit any adverse selection costs.