Genomic and Exomic Diagnostic Testing – ready for the doctor’s office?

This is an article from the National Institutes of Health that discusses the opportunities and challenges for making genomic (sequencing all 3 billion base pairs) or exomic (sequencing the 1-2% of the genome that contains the 20,000 genes that encode proteins) a routine test in the doctor’s office.  The study was conducted by the National Human Genomic Research Institute – see report.

The opportunity:

In an NHGRI-funded study published in the NEJM last year, exome sequencing identified the genetic cause of disease in about 25 percent of patients. The technique has identified causative or contributory gene variants in a host of diseases, including Charcot-Marie-Tooth disease, mental retardation, other neuropathies, metabolic disorders, epilepsy, cardiomyopathy, cancer and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease).

“This is a transformative moment in the history of medicine as we begin to integrate genome sequencing into the care of patients,” said Dr. Robert Green, who leads the NHGRI-funded MedSeq™ Project and several other translational genomics research projects at Brigham and Women’s Hospital and Harvard Medical School. “While our focus in this article is on the use of sequencing in cases where diagnosis is difficult, the sequence is just the beginning. We can expect these technologies to help us transition our entire approach in medicine to more personalized and preventive care.”

The challenge;

Physicians must learn which disorders are appropriate for such testing, what family histories suggest a single-gene cause, and how to interpret ambiguous results when a test points to a gene or several genes that might be responsible, Dr. Biesecker said. “If you’re willing to learn those things, I think you can use the test clinically,” he said. “If you’re not willing to learn those things, you probably shouldn’t be ordering the test, and you probably should refer the patient to somebody who is willing to learn these things.”

Some experts have questioned whether genome and exome sequencing is ready for broad application — or more precisely, whether the medical community is well enough versed in genetics to recognize the strengths and weaknesses of the testing. The authors note that, ready or not, the technology is here, physicians are ordering genome and exome sequencing for their patients and use will only increase.

The main issue is of EDUCATION regarding the biology of genetics in disease and the medical implications of genetic findings, which much of the time is equivocal.  Can busy doctors offices handle the ambiguity and nuance associated with genomic and exomic sequencing, or, is it best reserved for specialized centers?

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