Challenges remain before docs use whole-genome sequencing to diagnose disease

Before doctors use technology to evaluate every "letter" in a person's DNA to detect or diagnose medical conditions, several hurdles must be overcome, according to a new study.

Researchers found that sequencing a person's whole genome - all three billion or so DNA nucleotides in the chromosomes - required a significant amount of manpower for a small payoff.

They also found that identifications of potentially significant variations were not always reliable and doctors disagreed on how to proceed.

One of the study's authors said the cost of sequencing a person's entire genome has dropped in recent years, but the technology has been mostly used for research.

"We thought the time had come to do a small pilot study of patients in the clinical setting," Dr. Euan Ashley told Reuters Health.

Ashley is a specialist in genomics and medicine at the Stanford School of Medicine in California.

For the new study published in JAMA, he and his colleagues recruited 12 unrelated people between November 2011 and March 2012 to have their full genomes sequenced.

The goal was to see how whole-genome sequencing may work in a real-world setting, such as a hospital or doctor's office.

After drawing blood from the participants, the researchers sent all twelve samples to be sequenced by one large company and nine of the samples were also sent to a second sequencing company to see how comparable the sequence results would be.

The two sets of sequences mostly agreed when it came to common genetic variants (versions) of genes, but there were greater differences in the results among less common variants. For about 10 percent to 19 percent of genes that may be related to inherited diseases, the sequences were not reliable enough to ensure accuracy.

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Challenges remain before docs use whole-genome sequencing to diagnose disease