Being in intensive care is bad enough, but it can be even worse if doctors don鈥檛 know the cause of your illness or how to treat you. DNA sequencing, however, could give a diagnosis for about 1 in 9 young adults being treated in intensive care, a US study suggests.
Most of the previously unsuspected genetic conditions discovered via this approach involved a weak heart or blood vessels, or a predisposition to cancer.
The findings come from a study where the genetic analysis was applied to stored blood samples, after the person had been in hospital, rather than while they were still critically ill. But the results show that this approach could be used to change patient care while someone is in hospital, as the sequencing took about one week and would cost only around $2000 per person, says researcher at the University of Pennsylvania in Philadelphia.
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Doctors can already order a test of a single gene for someone whose symptoms indicate they may have a certain genetic condition.
If a person鈥檚 symptoms are puzzling doctors, it is also possible to sequence all of someone鈥檚 DNA, known as their genome. This is rarely done for adults, as it is so expensive, but it is starting to be carried out for critically ill babies and children, as serious genetic conditions are more likely to show up in infancy.
Drivas wondered if genetic sequencing might also aid diagnoses for young or middle-aged adults in intensive care. To reduce costs, his team only analysed the portion of the genome that codes for proteins. Called the exome, this makes up about 1 per cent of the human genome, but covers most of the known disease-causing genetic variants. Previous studies have suggested that exome sequencing offers .
The researchers looked at 365 people aged between 18 and 40 who had been admitted to intensive care and had their exome sequenced as part of a long-term study called the Penn Medicine BioBank, either before or after their hospital stay.
They found that, in 25 per cent of cases, the results would have led to a diagnosis for the condition that sent the person to hospital. In about 11 per cent of the 365 people, it wasn鈥檛 already known that they had the genetic condition.
People were less likely to already know about their condition if they were Black or Hispanic than if they were white, the team found.
If the testing had been done while the person was in hospital, in most cases, the genetic condition would have pointed to a specific treatment, says Drivas. And even if there is no treatment, it can still be helpful for people and their families to know the cause of an illness, he says. 鈥淎 diagnosis can [provide] closure and understanding,鈥� he says. 鈥淚n some cases, a diagnosis tells us that we can focus more on symptomatic management rather than trying heroic efforts that will not extend life.鈥�
at the University of Melbourne in Australia says some hospitals occasionally offer genome or exome sequencing for adults, but it is unclear how helpful it is. 鈥淭his is a very important study in that it produces some evidence,鈥� she says. 鈥淣ow we need to check it鈥檚 useful when used in day-to-day clinical care.鈥�
medRxiv
