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DNA sequencing is getting faster and cheaper, and it has been used to diagnose rare disorders in very sick children. But should it become a standard practice for healthy newborns? That鈥檚 the question asked by the BabySeq project, which has just released results from the first phase of its study.

The sequencing trial included 32 sick infants in the intensive care units at three Boston-area hospitals, and 127 healthy children enrolled through the nursery at Brigham and Women鈥檚 Hospital in Boston.

140 of the 159 sequenced newborns were carriers of one or more genes associated with disease 鈥� they have the potential to pass these genes on to their children, but they are not at risk for the disease themselves. 鈥淎lmost everybody is a carrier for recessive conditions. That鈥檚 what we would expect,鈥� says Alan Beggs at Boston Children鈥檚 Hospital, who led the study.

Of the sequenced group of babies, 9.4 per cent had genetic mutations that can result in childhood-onset diseases that can be treated with early intervention, such as heart disease or hearing loss. Eight babies had mutations that predict an adverse reaction to particular medications. One infant was found to have a deficiency in the enzyme biotinidase, which can lead to skin rash, hair loss and seizures. Their diet was supplemented with biotin to prevent such disease.

Beggs says there are clear benefits to genomic sequencing, but there are also potential drawbacks. There is a concern over potential future discrimination by health or life insurers, or even future employers. A genetic test could also lead a patient to undergo more medical procedures, which can be costly and risky. There鈥檚 also the psychological burden on the parents of knowing something bad may happen, but not being able to do something about it.

鈥淥ur criteria was to return results only for something that would manifest itself before the age of 18, to preserve the child鈥檚 autonomy, and to tell parents about something that is actionable,鈥� Beggs says. They also had a case where the child had a genetic variant tied to breast cancer, which is inherited, so they felt morally obliged to tell the mother of her own risk.

鈥淭hat is also beneficial to the child if you diagnose the condition in the mother and could potentially prevent critical illness or death of the mother,鈥� says Cynthia Powell at the University of North Carolina.

Beggs says the findings show that this kind of screening can be useful for healthy babies, and while it may not be necessary for all children, it could be done for a small subset of babies born with an obvious medical condition or those who have a particular family history of disease.

Powell says that the technology should be made widely available and not just limited to those who have the money to pay for genetic testing. But she points out that this would be a burden on public health systems.