Although one’s genetic liability is fixed from conception, the risk arising from one’s genes is dynamic, depending on changing factors such as age, environmental exposures, and previous illnesses. For example, if someone is at high genetic risk for alcohol/drug dependence but is never exposed to alcohol or drugs, the genetic risk is irrelevant. Even if sequencing at birth were to become standard clinical practice [42], communicating risk scores at birth is neither appropriate nor useful, and it is likely that genetic data would be stored and interrogated throughout life for both single-gene Mendelian disorders and common polygenic disorders. The decision to assess PRS might be triggered by age, onset of symptoms, family history, or presence of relevant environmental factors. The role that PRS will play in clinical care is currently unclear, and any use of PRS must be predicated on clear clinical utility, with a specific outcome activated by the score. For example, a PRS for coronary artery disease assessed in early adulthood may be useful to encourage healthy behaviour throughout life, although we still lack experience of how to
