That search has been elusive. When scientists sequenced the first human genome in 2000, geneticist Francis Collins, a leader of the Human Genome Project that accomplished the feat, declared that it would lead to a “complete transformation in therapeutic medicine” by 2020. But the human genome turned out to be far more complex than scientists had anticipated. Most disorders, it’s now clear, are caused by a complicated mix of genetic faults and environmental factors.

And even when a disease is caused by a defect in just one gene, like NGLY1 deficiency, fixing that defect is anything but simple. Scientists have tried for 30 years to perfect gene therapy, a method for replacing defective copies of genes with corrected ones. The first attempts used modified viruses to insert corrected genes into patients’ genomes. The idea appeared elegant on paper, but the first US gene therapy to treat an inherited disease—for blindness—was approved just last year. Now scientists are testing methods such as Crispr, which offers a far more precise way to edit DNA, to replace flawed genes with error-free ones.

Certainly, the genetics revolution has made single-mutation diseases easier to identify; there are roughly 7,000, with dozens of new ones discovered each year. But if it’s hard to find a treatment for common genetic diseases, it’s all but impossible for the very rare ones. There’s no incentive for established companies to study them; the potential market is so small that a cure will never be profitable.

Which is where the Wilseys—and the rest of the NGLY1 families—come in. Like a growing number of groups affected by rare genetic diseases, they’re leapfrogging pharmaceutical companies’ incentive structures, funding and organizing their own research in search of a cure. And they’re trying many of the same approaches that Silicon Valley entrepreneurs have used for decades.

At 10:30 on a recent Monday morning, Grace is in Spanish class. The delicate 8-year-old with wavy brown hair twisted back into a ponytail sits in her activity chair—a maneuverable kid-sized wheelchair. Her teacher passes out rectangular pieces of paper, instructing the students to make name tags.

Grace grabs her paper and chews it. Her aide gently takes the paper from Grace’s mouth and puts it on Grace’s desk. The aide produces a plastic baggie of giant-sized crayons shaped like cylindrical blocks; they’re easier for Grace to hold than the standard Crayolas that her public school classmates are using.

Grace's NGLY1 deficiency keeps her from speaking. BLAKE FARRINGTON At her school, a therapist helps her communicate. BLAKE FARRINGTON

The other kids have written their names and are now decorating their name tags.

“Are we allowed to draw zombies for the decorations?” one boy asks, as Grace mouths her crayons through the baggie.

Grace’s aide selects a blue crayon, puts it in Grace’s hand, and closes her hand over Grace’s. She guides Grace’s hand, drawing letters on the paper: “G-R-A-C-E.”

Grace lives with profound mental and physical disabilities. After she was born in 2009, her bewildering list of symptoms—weak muscles, difficulty eating, failure to thrive, liver damage, dry eyes, poor sleep—confounded every doctor she encountered. Grace didn’t toddle until she was three and still needs help using the toilet. She doesn’t speak and, like an infant, still grabs anything within arm’s reach and chews on it.

Her father wants to help her. The grandson of a prominent San Francisco philanthropist and a successful technology executive, Matt Wilsey graduated from Stanford, where he became friends with a fellow undergraduate who would one day be Grace’s godmother: Chelsea Clinton. Wilsey went on to work in the Clinton White House, on George W. Bush’s presidential campaign, and in the Pentagon.

But it was his return to Silicon Valley that really prepared Wilsey for the challenge of his life. He worked in business development for startups, where he built small companies into multimillion-dollar firms. He negotiated a key deal between online retailer Zazzle and Disney, and later cofounded the online payments company Cardspring, where he brokered a pivotal deal with First Data, the largest payment processor in the world. He was chief revenue officer at Cardspring when four-year-old Grace was diagnosed as one of the first patients with NGLY1 deficiency in 2013—and when he learned there was no cure.