My patient is a middle aged professional, with no symptoms what so ever.

He is fit and healthy, a non smoker, has good teeth, eats well and has no family history of arthritis or autoimmune disease. So why is he seeing a rheumatologist?

He’s concerned about some results he has received from a genetic screening test. The test results suggest that his risk of developing two autoimmune diseases – rheumatoid arthritis and Scleroderma, conditions I frequently treat, is increased.

I’m at a slight disadvantage as this is the first time I’ve had has to counsel a patient in this situation.

There’s an additional complicating factor. The patient is me.

Eric Topol, in his book, The Creative Destruction of Medicine, describes how genetic health screening will be one of the key drivers of a shift towards personalised medicine. So, a few months back, I signed up to a service provided by the genetic screening company 23andMe, which offered a personalised screening test for $178 (On the request of the FDA, 23andMe no longer offer a health screening service).

Shortly afterwards, a courier collected a small vial of my saliva and then delivered it to a US based lab. 6 weeks later an email arrived with the results.

In arranging for the test to be performed, I broke two of my usual rules as a doctor; don’t try and practice medicine on yourself (I usually outsource my personal medical care to my excellent GP) and don’t request a test where you don’t know what to do with the answer.

I went to medical school and learnt about DNA, RNA and Mendelian inheritance. Through osmosis at medical conferences and by reading the background literature, I have acquired enough genetics knowledge to bluff at a dinner party of non geneticists. But with the exception of ‘need to know’ knowledge (specific to a fairly small number of diseases) my genetics knowledge is fairly limited.

Unfortunately these tests have not yet been validated in a clinical setting so there’s no real guidance for physicians like me trying to interpret these tests; What are the pitfalls and likelihood of a false positive or a false negative test? What is predictive value of a positive test? How reassuring is a negative test and how do these genetic risk factors interact with environmental factors to increase the risk of developing a specific disease like RA or scleroderma?

If I struggle as a doctor to put this information in context, how can I counsel and guide my patient? Until I have some I’m inclined to avoid answering. I’m going to get my patient to come back and see me in a few years’ time.

Further reading
NEJM series on Genomic Medicine
Dr. Robert West’s personalised medicine blog

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