Thursday, January 01, 2015

Gene-environment interactions and the modesty of 2014 personalized medicine: Obesity, Reefer madness

Between 2007 and 2008 my work life got unusually exciting. Most of the time I work on software development in well understood aspects of medicine, but back then we were, once again, super-excited about genomics and “personalized medicine”. I made a couple of funded trips to meet with Stanford research teams maintaining genomic ontologies. I had a blast using exciting tools for navigating poorly maintained and unreliable massive web UI databases of gene-phenotype relationships.

At last we were going to realize the NIH predictions of 1994 — 10 years late, but better late then never.

Then the hammer fell. My 2008 post on schizophrenia [1] doesn’t talk about the work I was doing then, but it explains why we gave up. The disorders we cared about, schizophrenia, diabetes, lipid disorders, depression and so on, didn’t have a handful of generic recipes. Turns out there are hundreds, or thousands, or “recipes” for schizophrenia made up of environment (especially intra-uterine) and lots and lots of interacting genes. Even worse — lots of seemingly “normal” minds run on brains built with buggy genomics. Turned out “family” (genetic relative) history was a much more useful guide to predicting disease and treatment than genomic analysis — and that didn’t justify big investments.

Everything stopped, and then health care IT turned from the excitement of personalized medicine to the painful tedium of “meaningful use” and the more scientifically tractable domain of population health.

I still follow the field of course, and there has been slow but interesting progress …

Gene Linked to Obesity Hasn’t Always Been a Problem, Study Finds

… In 2007, researchers discovered that people with a common variant of FTO tend to be heavier than those without it. … Two copies of the gene bring 7 extra pounds — and increase a person’s risk of becoming obese by 50 percent.

… A new study shows that FTO became a risk only in people born after World War II.

… A variant of a gene called AKT1, for example, can raise the risk of psychosis — but only if the carrier smokes a lot of marijuana….

Small progress admittedly, but scientifically interesting. Exercise is good for most things — but we know that for most people moderate exercise [2] doesn’t add much to dietary control of weight. For people with the FTO gene though, exercise might indeed control weight. People with AKT1 are susceptible to persistent Reefer Madness — they really shouldn’t use marijuana [3]. In a related vein, there’s some evidence that the dementia protection of exercise is much stronger in the 14% of Americans with the APOE4 gene variant [4] than in APOE4 negative populations.

Progress — but darned slow. At this rate it will take decades to build what we expected before the year 2000.

- fn -

[1] Quite a good post, if I say so myself. I’d forgotten autism was once considered a variant of pediatric schizophrenia. We’re again merging both of those diagnostic categories.

[2] Extreme exercise is another matter, but one that’s rather hard to study. Though there is this recent NYT article on super-short higher intensity workouts that are to CrossFit as a snack is to a smorgasbord.

[3] Incidentally, marijuana legalization will be a boon to addiction medicine. Investors now include rehab clinics in the category of cannabis business opportunities.

[4] Why is a nasty gene so prevalent? The Wikipedia article mentions APOE4 helps with Vitamin D update — a particular problem in northern europeans. We presume it does have some survival advantage in some settings.

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