Whole genome sequencing is becoming more popular in medical research. With its falling cost and increasing reliability, some scientists hail the process as being the future of genetic research. But should whole genome sequencing be used as a part of newborn screening programs? This is a question that researchers from McGill University in Canada say should be addressed.
The human genome is made up of over 3 billion genetic letters - A, C, G, and T. These are known as DNA nucleotides and represent pieces of DNA called adenine, cytosine, guanine and thymine. Whole genome sequencing (WGS) involves using advanced technology to determine the order of these nucleotides within the genome.
As well as enabling quicker and simpler gene discovery, scientists say that WGS may reveal previously unknown genes that contribute to diseases and that the process could lead to personalized treatment methods. Furthermore, WGS could lead to identification of lifestyle and environmental factors that affect genetic predisposition.
As a result of these potential benefits, some scientists say WGS should be offered as part of newborn screening programs.
At present, more than 60 countries have newborn screening programs. These include a blood spot test, which involves taking a few drops of blood from a newborn's heel and testing the blood for genetic, endocrine and metabolic disorders, including sickle cell disease and cystic fibrosis.
But some researchers say that using WGS in newborn screening could aid detection and management of a much wider range of disorders.
However, in an article recently published in the journal Science Translational Medicine, McGill University researchers say newborn WGS raises ethical, legal and social issues that "need to be weighed carefully."
Considerations for WGS in newborn screening
In their article, Prof. Bartha M. Knoppers and colleagues have outlined a series of considerations that they say should be addressed before WGS is introduced in newborn screening.
Should WGS be a part of newborn screening programs? McGill University researchers say clear policy direction and public discussion is needed first.
First of all, they point out that WGS can generate large amounts of information - possibly too much. For example, the technology may reveal incidental findings, such as paternal information or reproductive risks. It may also reveal conditions that will not develop until the child becomes an adult.
As a possible solution to this problem, the authors say that only pediatric conditions should be communicated to parents and other results from WGS can be disclosed at a later time.
The authors say that WGS in newborn screening would mean huge revamps for public health care systems so that they could cope with the large amounts of information.
Furthermore, they point out that this additional information could lead to more false-positive results, which would impose a burden on both health care resources and families.
Although WGS is increasing in popularity, the authors say many clinicians are not trained in genetics. Introducing WGS in newborn screening would mean that education and training in genetics and genomics would need to be offered to both clinicians and parents.
The majority of newborn screening programs are mandated by law, meaning parental consent is not needed for the tests to go ahead. But the authors say that WGS may not always directly benefit the infant in childhood, therefore obtaining parental consent should be considered.
Other points the authors say should be examined include:
- Validating genetic variants. The authors say it could be challenging for doctors to offer "a standardized and accurate interpretation of genetic variants."
- The best way to ensure the infant receives treatment and follow up. They say a report card for each infant would be "invaluable," particularly for those with single-gene disorders.
- How data for each patient should be stored.
- How WGS results should be communicated to patients over time.
- Insurability. Since WGS would be a part of the medical record, this could lead to insurance issues.
Commenting on the possibility of WGS in newborn screening, Prof. Knoppers says:
"Any change in newborn screening programs should be guided by what's in the best interests of the child. We must also tread carefully in interpreting the scientific validity and clinical usefulness of WGS results."
Co-author Karine Sénécal, of the Centre of Genomics and Policy at McGill University, adds that without clear policy direction and public discussion on WGS as a part of newborn screening, many more parents may choose to pay for the technology through private testing services in years to come.
"Medical and public education programs need to be put in place so that people understand the limits of whole-genome sequencing," she adds.
Medical News Today recently reported on a study investigating the benefits and drawbacks of WGS, which concluded that WGS is not ready for widespread use.
Written by Honor Whiteman