Jeff Segal, MD, JD, FACS

Remember how painful memorizing the Kreb’s Cycle was?

Try this. New patient walks in with a few freshly printed documents. He just plopped down a few hundred bucks for a personalized genetic profile – offered by 23andme, Decode, or any number of other direct-to-consumer vendors.

He points to SNP results linked to 9P21. He findings state Rs2383207 (G:G); Rs1333049 (C:C); and Rs10757274 (G:G). He’s heard these markers might bode poorly for heart attack.

“Doc, what do YOU think?”

Kreb’s Cycle doesn’t seem so hard now, does it?

Welcome to the exploding world of personalized medicine. There are several thousand discrete gene tests which can identify isolated single nucleotide polymorphisms. These SNPs sometimes predict if populations are at higher risk for certain diseases. Whether such findings are strong; weak, or fleeting or even applicable to individuals remains to be seen.

Sequencing the entire genome at one time cost millions of dollars. Today, some companies are offering raw data (sans interpretation) for under $10,000.

What responsibility do you have for interpreting tests not approved by the FDA? What about not ordering genetic tests for your patients? What about tests looking at genes that might impact drug metabolism – for example Coumadin or Plavix.

Interestingly, there is not much case law on these issues. And to make matters more challenging, many insurance carriers will not pay for some genetic tests.

If you are comfortable with the literature and making recommendations, then by all means do so. If not, consider referring the patient to a genetic counselor for guidance.

Finally, should you order genetic tests when prescribing drugs that impact metabolism? Maybe. I am no expert on pharmacogenomics. If the risk of getting the dose wrong is great; and the clinical effects of getting the dose wrong are significant, I personally would write the order to help guide treatment. What would you do?

Citrate → cis-Acontiate → Isocitrate → alpha-Keotglutarate….