To be insurable, a risk must meet certain criteria. One is that the loss must not be catastrophic. Another is that the loss must be unexpected or accidental.

Genetic testing renders many health risks uninsurable. For example, about 30,000 people in the United States have two copies of the gene that causes cystic fibrosis (CF). Treatment for CF is improving. The average lifespan for people with CF is now 37 years, but for an insurer, those are 37 years of costly treatment. New advances in gene therapy are likely to extend life further, but at even greater cost. Losses from CF are catastrophic, and, since genetic testing can diagnose CF even before birth, the loss is not unexpected or accidental. CF is thus uninsurable by traditional standards.

Single-gene genetic disorders like CF are fortunately rare, but new research by a team led by Lisa Bastarache of Vanderbilt University, published last week in Science, has the potential to greatly enlarge the number of people with uninsurable genetic risks. The authors used a large data base to identify cases in which the interaction of multiple genes produces diseases that are not as easy to spot as CF. They found 807 people with potentially dangerous genetic patterns among 21,701 that they screened. Only 8 of them had been previously diagnosed as being at risk of genetic disease.

A 100-fold increase in the number of people with potentially dangerous genetic patterns would be bad enough, but things might get even worse. Dr. Joshua Denny, one of the co-authors of the study, told the New York Times,

“I’m kind of surprised we found anything. The fact that we did means there’s maybe a lot out there that we don’t know.”

As improvements in genetic testing make the health risks of more people uninsurable in the commercial market, the case for guaranteeing access to health care by way of universal catastrophic coverage or something similar grows ever stronger.