Everything changed when the family learned about a study called IDIOM, led by Eric and Sarah Topol at the Scripps Translational Science Institute. IDIOM was an attempt to diagnose people with “serious, rare and perplexing health conditions” by sequencing their entire genomes and uncovering the faulty genes that presumably lay behind their problems. Lilly fit the bill perfectly. She became the first IDIOM volunteer—and its most successful by far.

Within Lilly’s DNA, the Scripps team found a mutation in a gene called ADCY5, which is highly active in parts of the brain involved in coordinating movements. Based on these results, Lilly's doctor decided to try her on a drug called Diamox, which had helped the only other known family with faults in ADCY5 (more on them later). When Lilly tried the drug, she started sleeping soundly for the first time in years.

When I first spoke to the Grossmans in 2013, they had just celebrated Lilly's 16th birthday. “That was the first one where we’ve known that Lilly will be here on her next one,” Gay told me. “That alone was worth the sequencing. It bought us time. We always thought there wasn’t much time.”

I caught up with them again last month. With Lilly about to start at college, their spirits are still up—and for reasons beyond simply buying time. Lilly's case has acted as a magnet for others with the same mutation. Families with the same problem read about Lilly’s case and contacted the Grossmans. Doctors and geneticists looked at their own patients and saw a new explanation behind puzzling symptoms. Before, there were isolated pockets of people around the world, dealing with their own problems, alone for all they knew. Now, there’s a community.

Gay Grossman

This is a trend. Take Matt and Christina Might. Their story, as recounted last year by Seth Mnookin in The New Yorker, has many of the same leitmotifs as the Grossmans’: a child, Bertrand, who suffered from a movement disorder at an early age; a long diagnostic odyssey of punishing tests and false leads; and a sequencing study that finally identified the gene behind his condition—NGLY1.

At the time of Bertrand's diagnosis, no one knew of any other patients with diseases caused by NGLY1 mutations. Those cases only came to light after Matt recounted the family's saga in a 5,000-word blog post, which then went viral. Within months, the Mights had been contacted by parents who had recently learned that their children had NGLY1 mutations, and scientists and doctors who had found (but often ignored) the same alterations in their patients' DNA.

The Grossmans’ story followed similar themes, with slight variations. For a start, at the time of Lilly's diagnosis, ADCY5 mutations had been implicated in disease. In 2012, Wendy Raskind at the University of Washington had pinpointed the gene as the culprit behind a movement disorder affecting a German family, whose symptoms—jerky, involuntary spasms of the face, head, neck and arms—were similar to Lilly's. Raskind called the condition “familial dyskinesia with facial myokymia” (FDMD) and although she had been studying it for 11 years, she didn't know of any other cases besides that one family.