Many people think that personal genomics will change medicine. Doctors will choose treatments based on your genome, learning your genome will tell you what diseases you are at high risk of so you can take precautions, and so on. One person who believes this is Eric Topol. In his new book, The Creative Destruction of Medicine, he writes:
The biggest leap came in the first decade of the twenty-first century. The six billion bases of the human genome were sequenced, and this led to the discovery of the underpinnings of over one hundred common diseases, including most cancers, heart disease, diabetes, autoimmune disorders, and neurologic conditions.
Here is the founder of a company that makes sequencers: ““I believe that the impact on the medical community of whole human genome sequencing at a cost comparable to a comprehensive blood test will be profound.”
I disagree. I have seen nothing that suggests genes make a big difference in any common disease and plenty that suggests environment makes a big difference. My self-experimentation led me to one powerful environmental factor after another, for example. Biologists have invested heavily in the study of genes for reasons that have nothing to do with practical applications, as Thorstein Veblen would be the first to point out.
In 1999, New Yorker staff writer Michael Specter wrote an admiring article about a neurology professor named Kari Stefansson. Stefansson had returned to his native Iceland to take advantage of Iceland’s genetic homogeneity to find genes for common diseases. “In the past, drugs were discovered almost by chance,” Specter wrote, as if this would soon change. The wishful thinking involved is indicated by passages like this:
[Stefansson] and Gulcher selected the five per cent of Icelanders among the hundreds of thousands in their genealogical database who had lived the longest— most of them over ninety. The database allowed the two scientists to seek an answer to a simple question: Are these people who live so long related to each other more often than the average in Iceland? The answer quickly became apparent. People over ninety are much more closely related to each other than people in the general population are, and their children are more likely to live longer than the children of others. That provides strong evidence that the trait is inherited.
“Strong” evidence? The “people over ninety” observation is strong evidence that longevity is inherited only if relatives share nothing but genes. The “their children are more likely” observation is strong evidence of genetic control only if parents pass on to their children only genes. Both assumptions are highly unlikely. For example, surely an Icelandic person lives closer to his relatives than to randomly selected Icelanders.
The article quotes no one with my view (geneticists are overstating the practical value of their work), but it does say that “Stefansson set out to raise capital at a time  when investors had become skeptical about the many unfulfilled promises made by companies claiming that genetic research would solve the ills of humanity.”
Will reality overtake hype? Here is an indication this is happening:
Kari [Stefansson], a neurologist, was a Harvard professor when he co-founded deCODE in 1996. Two years later, Iceland’s parliament gave deCODE access to one of the country’s unique resources—health records of the genetically homogenous population. DeCODE debuted on the NASDAQ stock exchange in 2000, and it made dramatic discoveries of genetic factors associated with cancer, heart disease and other conditions. But the company never turned a profit and filed for bankruptcy protection in 2009.