“DNA tests for every baby on the NHS”

This was the headline on the front page of the UK national newspaper The Daily Telegraph on Saturday 21^st June 2025. Laura Donnelly in her article reported that the National Health Service would introduce whole genome sequencing for all newborn infants within a decade.

Wes Streeting, the UK Health Secretary, is reported as saying that such universal testing works to “leapfrog disease so we are in front of it rather than reacting to it” – essentially stating that prevention of disease is better than the treatment of disease. Few would disagree with this but there remains a major uncertainty which, stated simply, is how the information would be used to prevent disease.

Almost every person in the population is a carrier of an autosomal recessive disorder with little or no adverse effect on their health. They are carriers of disease, not people affected by disease. Universal whole genome sequencing has the potential of making everyone in the population being labelled as having a genetic disorder, with the unintended effect of transforming almost everyone in the population into a patient. The actual number will depend on the number of reported mutations and their prevalence. There is no point in someone knowing their carrier status if it has no benefit on their lives. However, it would be useful if whole genome sequencing were offered to couples considering marriage, planning a pregnancy or in pregnancy to determine whether both members of a couple share the same autosomal recessive mutation.^1–3 If they do, the couple have a one in four chance of being affected by the disease. Cystic fibrosis is an example. About 1 in 25 of the population are carriers: 1/25 × 1/25, i.e. 1/625 have a one in four chance of having a child with cystic fibrosis, i.e. 1 in 2500 people tested. While it would be reasonable for couples to be offered whole genome sequencing it would probably not be the case to do so at birth to identify autosomal recessive disorders.

Even homozygous autosomal mutations do not always lead to disease. Sometimes it is better to screen using phenotypic markers, for example standard biochemical markers of iron overload in screening for haemochromatosis.

A perceived benefit of performing whole genome sequencing on all newborns might be to identify children with developmental disorders but in the absence of a useful preventive intervention the case for such population-wide testing is slim. Genome analysis could usefully diagnose and explain some developmental disorders, obviating unnecessary clinical investigation. On the other hand, it would certainly raise anxiety and though health professionals may talk about a result being “actionable” the issue is not whether it prompts action but whether the action is useful. The justifiable concern is that such testing would lead to actions that have little or no influence on a clinical outcome and could be very expensive.

Another possible perceived application of universal whole genome sequencing is the use of polygenic risk scores in which a large number of DNA variants are used to predict disorders such as ischaemic heart disease, stroke and cancer. However, it has already been shown that such polygenic risk scores are poor predictors of disease,^4,5 whether considered on their own or in combination with risk factors such as serum cholesterol and blood pressure. ⁶

The use of whole genome sequencing at birth could go beyond the medical effects. It could extend to having a database of everyone's genome available for the investigation of serious crime such as rape. It would help identify the perpetrators of crime. It would have the advantage over identity cards in that they could not be shown on demand, which can readily be abused, but would still require public education and acceptance.

Whether whole genome sequencing can be useful is not the question. It is whether the universal application of such testing, as opposed to its selective use, would be worthwhile. The requirements of whole genome sequencing applied to a population should be judged in relation to the requirements of any medical screening test. ⁷

We suggest that further thought and discussion be given to how whole genome sequencing should be used to benefit the population.