1 The Numerator
I was born in 1964. While I continue to make peace with social networking, I still think of myself as too old to be an organic part of the exhibitionism on YouTube, Facebook, Twitter, and MySpace. At best I am a poseur. I play in an occasional rock band with some other forty-somethings, and while we have a MySpace page,1 none of us is terribly adept at using it. We have no idea, for example, how to program a âbotâ to troll cyberspace and accumulate âfriendsâ like so many chocolate Easter eggs; we have outsourced that kind of stuff to younger friends and to our children. We tend to be less mercenary than younger bands; we friend people we know and musicians we admire, never mind that in many cases theyâre dead (these days the definition of friendship doesnât even require that both parties be capable of drawing breath). In my band we will post pictures or movies of ourselves, but almost always with ambivalence, as we find them to be dorky, pretentious, or otherwise embarrassing. Like any collection of forty-five-year-olds still writing songs and performing them in dingy college-town bars on Friday nights for a dozen of their most patient, loyal, and sleepy friends, we are narcissists and stultifyingly vain, to be sure, but hey, at least weâre discriminating.
As much as I want to hide my potbelly (probably a sign of insulin resistance and determined by genes acting in concert with ice cream), I agreed to make my genomeâthe DNA sequence that I inherited from my parents and that is uniquely mine just as yours is uniquely yours*âan open book. And if you want to study my phenotypeâmy health records, my ongoing struggles with depression and infatuation with selective serotonin reuptake inhibitors, or my dubious diet, for exampleâthen go ahead, knock yourself out. Itâs all out thereâwith more to comeâon the Internet. For doing this, I and the other participants in the Harvard-sponsored Personal Genome Project2 have been lauded for our âbraveryâ by friends and colleagues, derided for our elitism and egotism by some social and genome scientists, and largely ignored by the medical establishment.
Are weâwere weâreally so brave? One of my favorite people who thinks about these things, Stanford law professor Hank Greely, said not long ago, âPeople believe in the magic of genes, and buy into the idea that they are the deepest secrets of our being. But maybe my credit card records come closer to being a deep secret of my being.â3
As of mid-2010, few âwholeâ human genomesâ had been sequencedâcertainly no more than a few hundred. But in the next couple of yearsâor monthsâthere will be thousands more, at least some of which will be widely shared with researchers or anyone whoâs interested. And the âgenome-liteâ versionâhaving a half million or two million DNA markers analyzed for a few hundred bucks by private companies rather than a full sequenceâis already a cheap commodity entrenched in the marketplace, much to the chagrin of many doctors and geneticists, and to the befuddlement of regulatory agencies.
What will this real-time experiment in science and radical openness mean? DNA sequencing may soon be cheap enough and reliable enough to make personal genomics as pervasive as cell phones, iPods, and LASIK surgery (assuming that, like those things, DNA sequences are actually useful).
But cheap sequencing and widespread sharing of genomic data will also bring with them âunintended consequences,â card-carrying bioethicistsâ second favorite phrase behind âslippery slope.â Nightmare scenarios include identity theft and loss of insurance.
On the other hand, even the leftiest and most passionate civil liberties advocates would have to concede that genetic discrimination is relatively rare: the two most notorious cases occurred several years ago. In one, Burlington Northern Santa Fe Railway was found to be surreptitiously testing its workers for a genetic variant thought to predispose to carpal tunnel syndrome (it doesnâtâthe company couldnât even figure out how to discriminate right); the railroad settled with thirty-six workers for $2.2 million in 2002.4 In the other high-profile case, the Lawrence Berkeley National Laboratory was accused of having tested several of its employees for syphilis, sickle-cell anemia, and pregnancy without their consent. The lab settled in 1999, again for the magic sum of $2.2 million.5 One presumes that in both cases the employers would have used positive test results (pregnancy?!) to justify denying the employeesâ insurance, raising their out-of-pocket costs for health benefits, or perhaps even firing them.
Again, two cases do not an epidemic make. But, as a former mentor of mine used to say, âAbsence of evidence is not evidence of absence.â Despite the lack of litigation, it may be that the temptation for employers to go all actuarial on their current and future employees is still too great. In 2005, for example, a higher-up at Walmart floated the idea of discouraging less healthy people from applying to work at the company, as a way of holding down health-care costs. In her memo, the vice president noted that Walmart workers tend to develop obesity-relatedâand partly geneticâdiseases such as diabetes and heart disease at a higher rate than the national population (at the time, less than 45 percent of Walmartâs employees had company health insurance).6 More disturbing, in 2007 an exposĂ© in the Los Angeles Times revealed that the U.S. military regularly practiced genetic discrimination. On a number of occasions servicemen and women with genetic conditions have found themselves kicked to the curb, with the armed forces arguing that in such cases they bear no responsibility for soldiersâ health and disability benefits: you may have lost a limb in Fallujah, but your retinitis pigmentosa is preexisting, so, you know, sorry. Military doctors were said to discourage their patients from getting genetic tests.7
As I worked through drafts of this book, the world kept changing. The military has since revised its draconian policies on preexisting conditions.8 And in May 2008, the Genetic Information Nondiscrimination Act (GINA) passed both houses of Congress and was signed by President George W. Bush.9 Twelve years in the making, it was the end of a long and tortuous road for patient activists and a rare kumbaya moment in Washington in the post-9/11 Bush era.
But GINA was not and will not be a panacea: it is limited to employment and health insurance. It says nothing about life, disability, or long-term care insurance, all of which are likely to be of greater interest to insurance companies and to Alzheimerâs patients and their families. Thus, if an insurer wants to deny you coverage or charge you exorbitant fees because you carry two copies of the APOE allele* that raises your risk of developing Alzheimerâs fifteen-fold,10 GINA can do nothing to influence those insurers.11
And its power over employers will be tested. Recently Pamela Fink of Fairfield, Connecticut, found out that she carried a mutation in BRCA2, one of the two most powerful hereditary breast cancer susceptibility genes. Despite years of glowing reviews from her employer, MXenergy, after she shared her results with her bosses, she was demoted and eventually fired.12
And I was gonna put my entire DNA sequence on the Web?
I wasnât going to win any prizes for originality or brilliance, but to my motherâs and my own surprise, I had stuck it out and gotten my doctoral degree in genetics. I had spent the previous five years studying a rare birth defect called Hirschsprungâs disease, named for the nineteenth-century Danish physician who first described it. It is also sometimes referred to by the even more unwieldy name âcongenital aganglionic megacolon.â13 Our gastrointestinal tract has its own primitive brain: the enteric nervous system.14 Given that the adult intestinal tract is twenty-five feet long, itâs not surprising that it requires some local neuronal signals to keep things moving along. Hirschsprungâs disease occurs when, during early embryonic development, those neurons fail to take up residence in some part of the gut. Usually the few inches closest to the rectum are affectedâthis makes sense since those are the cells that will have traveled the farthest as the embryo grows.
The Hirschsprungâs patient has great difficulty moving his bowels past the part without nerve cellsâeverything stalls. The bit just before the aganglionic segment swells, sometimes to the size of a football. Any competent pediatric surgery resident can look at an X-ray of a newborn Hirschsprung babyâs distended gut and make a reasonable guess at the diagnosis, which is confirmed by biopsy.15
Unlike most strongly genetic diseases, Hirschsprungâs disease is highly treatable. Typically, once the diagnosis is made, a baby will have a colostomy procedure. He will then go home for six months to allow his intestines to grow. He will then return to the hospital, where the surgeon will perform a series of biopsies to locate exactly where in the gut the nerves stop. The surgeon will then resect the aganglionic part of the bowel. Six weeks later the surgeon will reverse the colostomy (some surgeons will dispense with the colostomy and try to repair the gut in a single surgery). Although most Hirschsprungâs babies will grow up to lead normal lives, they are forever susceptible to severe constipation and potentially life-threatening infections of the bowel.16
Hirschsprungâs is a stand-in for other complex diseases; that is, ones caused by some mixture of genes and the environment. I was part of one of two teams that found a major clue leading to the identification of the most important susceptibility gene.17
At some point during my first postdoctoral year, laboratory science began to lose its luster. I looked at those around me and saw the lives they were leading: the grant applications, the boring meetings, the parade of mind-numbing seminars, and the neurotic graduate students who required some mysterious combination of hand-holding, babysitting, thoughtful mentoring, and tough love. It was not nearly as much fun as it used to be.
And I was Hirschsprunged out. I took some measure of satisfaction in knowing that I was helping to elucidate the biology of the disease and that my work might play some small part in creating better diagnostics or therapies. But somehow it wasnât enough. As tragic diseases go, I suspect even most Hirschsprungâs families would admit that their plight is not in the same league as those with a loved one suffering from Lou Gehrigâs or late-stage lung cancer or Tay-Sachs. Instead, here was a genetic disease that was actually treatable or, as personal genomics partisans like to say, âactionable.â At the time I wondered if anyone really cared about what we were doing. Genetic research has beenâand continues to beâcriticized for throwing lots of resources at rare diseases, and I suppose I worried that I was part of the problem. The genetic aspects of the disease I studied were fascinating, but we were a small, insular community studying a small, mostly treatable disease affecting one in five thousand kids.18
Meanwhile, molecular genetics was changing at a pace that, more and more, left me dizzy and exhausted. The seminars I attended may as well have been in Esperanto. I was falling behind. Science had revealed to me with much clarity that I was now a full-grown, thirty-three-year-old dinosaur. Staying in the game would mean assimilating massive amounts of biochemistry, deep and broad computational skills, or both. Genetics was becoming genomics, a digital science, and one ought to have had more of a quantitative clue than I did. I had a choice: I could change or die.
I decided to die.
I left laboratory genetics. I worked as a market researcher, feckless financial manager (I know those words seem redundant these days), biotech consultant, and science editor. Over the next seven years I rarely thought about Hirschsprungâs disease. Once in a while I might stumble upon a paper by my advisorâs group or other people I knew describing some novel finding that, if I really followed the paper trail, I might be able to trace back to my own work ten to fifteen years earlier.
But in 2005, Hirschsprungâs reappeared in my life in a sudden, unlikely, and disturbing way, like a drunken ex turning up at oneâs wedding. Wielding a knife. On December 14, the eve of my motherâs birthday, my nephew Jesse was born with a dilated colon. Three days later he was diagnosed with Hirschsprungâs disease.
What did it mean? my family wondered aloud. I knew the question was both clinical and existential, though I could supply neither type of answer. What was going to happen to my brotherâs new son and my parentsâ last grandchild? I hadnât a clue. I immediately became the Expert, though I remembered little. I was as flummoxed as my family was, but out of love, hubris, and a desire to be a hero, I did not betray my ignorance. I took my thesis off the shelf for the first time in years. I sent emails and made phone calls to people who still âdidâ Hirschsprungâs. I reread articles about pediatric surgery techniques, the details of which Iâd once known cold.
As my heartbroken and sleep-deprived brother and sister-in-law watched their new baby go in and out of the hospital again and again, I was overtaken by a sort of numbness, a paralysis. How strangeâhow impossible!âthat the rare disease Iâd devoted eight years to understanding was suddenly no longer an intellectual abstraction, a genetic problem to be solved in a lab or on a computer. Someone in my family was to have five surgeries over the first year of his life, with still more to come. Someoneâor someonesâin my family had to change colostomy bags and purchase boatloads of strange dietary supplements and be on constant guard for signs of infection. I thought of my previous incarnation and the Hirschsprung families who would occasionally call the lab. I remembered their need to tell me their stories. I remembered feeling awkward at not being able to empathize. My two-plus years of training as a genetic counselor had failed me. I knew more about Bayesian risk estimates than I did about what to actually say to the grief-stricken mother of a sick newborn. I was mostly useless. But how could I possibly empathize? I was not one of them.
Now I wondered about Jesse. What if he carried one of the mutations I had identified ten years earlier?19 What if my brother did? What if I did? And what did it mean?
God, I decided, was fucking with us.
I called my brother on the phone one day. He was tired and loopy after another night on the foldout chair in the hospital. âHowâs it going?â I said. An absurd question and a pretty feeble conve...