Clinical Genomics

By March 13, 2014 Commentary

It has been well over a decade since the human genome was first sequenced and the pace of integration of genomic knowledge into clinical practice has been quite slow.  One of the primary areas where there have been a number of advances is pharmacogenomics.  An article in the Journal of the American Medical Association describes a pilot effort at Stanford to use whole genome sequencing to guide clinical practice.   (JAMA Article)   The cost of whole genome sequencing has dropped to around $1000, although a really comprehensive and trustworthy report of an individual’s genome and associated biochemistry would cost several times that.  Stanford’s Medical School did a pilot on 12 volunteers to ascertain what would be involved in trying to use whole genome sequencing to help guide medical care of a patient.  Each genome was sequenced twice, by different companies.  Reports were developed from databases of standard genetic variants and disease associations.  The two sequencing efforts had very highly similar results in most cases but there were differences in some specific types of genetic variations, which raises the usual concerns about any diagnostic test–you must have a very high degree of confidence in its accuracy before you can use it for clinical purposes.  The total cost for sequencing and writing a report on patient-specific risks was around $14,500 per person; which is not a cost the system is likely to want to bear.  Six individuals with different professional backgrounds did the genomic interpretation and there was not always a high level of interpretive agreement.  Another interesting finding was that 11 of the 12 tested people had at least one known variant affecting drug metabolism.  This area of pharmacogenomics seems particularly important as an aid to prescribing and monitoring of drug therapies and probably will be the first area to become a routine test for all patients.   The process of genome sequencing and interpreting is not only costly itself, it would in this pilot have generated significant follow-up costs through additional testing and referrals to physicians to further evaluate disease risks.  The promise of genomics to provide truly individualized care is great, but only if the information is trustworthy and the clinical significance is clear.

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