DNA studies could expose disease-linked genetic mutations in one in five individuals

20170707120000, Reshmin Kaur Cheema
DNA studies could expose disease-linked genetic mutations in one in five individuals
Scientists have identified at least one recessive mutation in all the participants through DNA testing.
The topic of DNA studies has been a highly debated and controversial one garnering mixed opinions.

On one side, there are clinicians who aspire to diagnose diseases – or at the very least, predict risk – with just a DNA scan. On the other end, clinicians disagree with the benefits of this test, as it might not be worth the emotional or economic cost.

Genome sequencing reveals risk of rare disease


Two studies have now evaluated the beneficial effects of DNA testing – one of them being the first randomised clinical trial that assesses whole genome sequencing in healthy individuals. Collectively, they conclude that risk markers for rare diseases or genetic mutations linked to cancers can be detected in one out five people tested.

“It's terrific that we are studying implementation of this new technology rather than ringing our hands and fretting about it without evidence,” Barbara Biesecker, a social and behavioural researcher at the National Human Genome Research Institute in Maryland, said.

In the first study, 100 healthy adults who relayed their family history to their primary care physician were recruited. An additional full genomic workup – costing about USD5,000 each – was undertaken by 50 of the individuals. Scientists examined about five million subtle DNA sequence alterations across 4,600 genes.

Out of these, 11 had changes in at least one DNA letter, which potentially points towards the development of a, usually rare, disease. Two of them were symptomatic.

One of the 11 patients was discovered to have extreme sensitivity to the sun and her DNA revealed that she had a skin condition called variegate porphyria.

“Now that patient knows they will be much less likely to get bad sunburns or rashes if they avoid the sun and certain medications,” says Jason Vassy, lead author of the study.

More participants in genome group referred for further risk evaluation


Besides this, it was found that all the participants tested carried at least one recessive mutation. Scientists believe this knowledge can be useful in reproductive decision-making. For instance, the individuals’ partner can get tested for the same mutation and family members can test to see if they are carriers.

The team also evaluated participants’ chances of developing eight polygenic diseases. The collective effects of multiple genes were accumulated to predict a patient’s relative risk of developing the disease. In total, 60 genes were collected for coronary heart disease and up to 70 for type 2 diabetes. Vassy claims this was a “slightly more controversial result”.

Out of the 50 who only reported their family history, 16% were referred to genetic counsellors or had consecutive laboratory tests. In the DNA sequencing group, it was 34%.

Healthcare providers and insurance agencies question future use


Certain researchers have voiced concerns over the increased medical costs and psychological harm genome screening could evoke. The initial cost of the sequencing was borne by the study but those in the sequencing group forked out an average of USD350 additional in healthcare costs over the following six months. No participants expressed changes in anxiety or depression six months after the study.

“The study was extremely well designed and very appropriately run,” says Barbara Koenig, a medical anthropologist who directs the University of California San Francisco Bioethics Program.

She added, “It is just hard to know how all this information is going to be brought together in our pretty dysfunctional healthcare system.”

Koenig also denoted the gene as an “important cultural icon” today but stated that it is still too early for this technology to be useful in the clinic.

Insurance agencies have also expressed interest in the results of – and access to – genetic data. This information could allow them to propose more personalised policies, potentially lower costs and improve risk assessment for policyholders.

In October last year, Gen Re, a life reinsurer said its survey of the public’s attitude to genetic testing discovered that a majority of people are keen to get tested for genetic conditions. The people believe it will aid in managing their health better.

Despite the fact that it might be a long time before insurance agencies use the data to set the level of cover, the industry is moving at a rapid pace to digitalise and utilise data analytics. Some believe that, someday, life and health insurers will manage to sway the government and public into using genetic testing for this purpose. MIMS

Read more:
3 diagnostic mysteries solved through DNA sequencing
Revisiting the Human Genome Project and other health studies for a more holistic view of genetic diseases
Personalised medicine: Tailored to fit each person’s genes

Sources:
http://www.sciencemag.org/news/2017/06/one-five-healthy-adults-may-carry-disease-related-genetic-mutations
https://www.verdict.co.uk/genetic-testing-become-dna-insurance/