Rare diseases often elude early diagnosis, remaining undetected until significant organ damage occurs. Recently, UK Health Secretary Wes Streeting announced a 10-year initiative to integrate genetic testing for specific rare conditions into the standard neonatal screening process across the UK. This approach aims to ensure early intervention before symptoms manifest, aligning with ongoing global viability programs in places like the US and Australia. Yet, questions arise about the scientific validity of such measures.

The genome, akin to a book written in a novel language, is only partially understood. Decades of research on high-risk families have shed light on some genetic mutations, but there remains limited knowledge about the implications of population-level genetic testing for those at low risk. While this screening may prove advantageous for certain children and families, it might also lead to unnecessary tests and treatments for others.

Many genetic conditions involve more than just a single genetic mutation. For example, individuals with a variant of the hnf4a gene and a strong family history of rare diabetes have a 75% risk of developing the condition; conversely, those with the same variant but without a family history face only a 10% risk. It is misleading to assume genetic variants behave uniformly across all populations. Perhaps families carrying the hnf4a variant lack other unrecognized protective genes, or specific environmental factors might interplay with genetic risks to lead to diabetes.

The proposed neonatal screening program presupposes that genetic variants linked to diseases signify equally high risks for all, which is rarely the case. The exploration of disease-related variations in healthy populations is just starting. Until this research is thorough, we will not know how many individuals carry a variant that does not result in illness, possibly due to other protective factors. Should we really subject newborns to genetic hypotheses?

Furthermore, ethical concerns emerge from this initiative. How do we secure informed consent from parents when testing for hundreds of conditions simultaneously? In the near future, a genetic database encompassing all living individuals could become a reality—what safeguards will exist for its use and protection?

Screening newborns is not new, but the scope of conditions included in this initiative, the complexity of interpreting results, and the sensitivity of the information gathered pose unique challenges. I worry that parents may feel compelled to accept the test, yet not all uncertainties will be appropriately managed. I fear that important early life stages could become burdened with unnecessary hospital visits. Additionally, the pressure on parents and pediatricians to decide on potentially invasive testing for healthy infants is concerning.

A prudent step would be to gather more data on the prevalence and behavior of genetic mutations in the wider population before utilizing genetic testing as a speculative screening tool for children. The potential benefits may be overshadowed by significant risks.

Suzanne O’Sullivan is a neurologist and author of The Age of Diagnosis: Illness, Health, and Why Medicine Went Too Far.