Scientists believe that Parkinson’s disease is in our genes. It may be in the water

Amy Lindberg settled Fast forward to life in Legon. She played tennis and jogged during her lunch breaks, and navigated the sprinklers in the turbulent Carolina summers. But something dark was lurking beneath her feet.

Sometime before 1953, a massive plume of trichlorethylene, or TCE, entered the groundwater under Camp Lejeune. TCE is an extremely effective solvent—one of those mid-century wonder chemicals—that quickly evaporates and dissolves any fat it touches. The source of the leak is debated, but the grunts on the base used TCE to maintain the machines, and the dry cleaner sprayed it on blue clothes. It was ubiquitous in Legion and all over America.

TCE also seemed benign, as you could rub it on your hands or inhale its fumes without feeling any immediate effects. It’s playing a longer game. For about 35 years, Marines and sailors who lived at Lejeune unwittingly breathed in vaporized TCE whenever they turned on a tap. The Navy, which oversees the Marine Corps, initially denied the existence of the toxic plume, then refused to acknowledge that it could affect Marines’ health. But as the Legion vets grew older, cancers and unexplained diseases began to haunt them at astonishing rates. Marines stationed at the base had a 35 percent higher risk of kidney cancer, a 47 percent higher risk of Hodgkin’s lymphoma, and a 68 percent higher risk of multiple myeloma. At the local cemetery, the section designated for infants had to be expanded.

Meanwhile, Langston spent the rest of the 1980s establishing the California Parkinson’s Foundation (later renamed the Parkinson’s Institute), a laboratory and treatment facility equipped with everything needed to finally uncover the cause of the disease. “We thought we would solve the problem,” Langston told me. Researchers affiliated with the institute created the first animal model of Parkinson’s disease, identified an insecticide called paraquat as being nearly chemically identical to MPTP, and demonstrated that farm workers who sprayed paraquat developed Parkinson’s disease at extremely high rates. They then showed that identical twins developed Parkinson’s disease at the same rate as fraternal twins, which would not make sense if the disease were purely genetic, since identical twins share DNA, while non-identical twins do not. They even noted forms of TCE as a possible cause of the disease, Langston says. The team believed that each discovery represented another nail in the coffin of the genetic theory of Parkinson’s disease.

But there was a problem. The Human Genome Project was launched in 1990, promising to usher in a new era of personalized medicine. The project’s goal, to identify all genes in humans, was radical, and by the time it was completed in 2000, specious comparisons with the moon landing were frequent. Then-President Bill Clinton said that revealing our genome would “revolutionize the diagnosis, prevention, and treatment of most, if not all, human diseases.”

But for Langston and his colleagues, the Human Genome Project sucks the air out of the environmental health field. Genetics has become “the 800-pound gorilla,” as one scientist put it. “All the research money went into genetics,” says Sam Goldman, who worked with Langston on the twin study. “It’s more exciting than epidemiology. It’s the newest tool, the biggest rocket.” A generation of young scientists has been trained to think of genetics and genomics as the default place to look for answers. “I describe science as a group of five-year-olds playing soccer,” says another researcher. “They all go to where the ball is, and run around the field in a herd.” The ball was definitely not environmental health. “Donors want a cure,” says Langston. “And they want it now.”