Genetic variants usually cause us no harm whatsoever, and aren’t usually detectable by any tests. But every once in a while, a variant prevents a gene from performing its usual function. These harmful errors are called mutations.

Occasionally, a child inherits a mutation from a parent. Mutations can prevent a gene from performing its usual function in the body, which can cause health problems. People who inherit these mutations may have a greater chance of developing a disease, such as cancer or high cholesterol, often at an earlier age.