Ten years ago, scientists discovered that some people are naturally missing working copies of a gene known as PCSK9. The consequences of the mutation were extraordinary. These people, including a Texas fitness instructor, a woman from Zimbabwe, and a 49-year-old Frenchman, had almost no bad cholesterol in their blood. Otherwise, they were perfectly normal.

Drug companies pounced on the clue. To lower cholesterol, they would also try to block PCSK9. Now two separate drugs that disable the gene’s activity are nearing FDA approval. People taking the medications have seen their cholesterol levels plummet dramatically, by 75 percent.

Regeneron Pharmaceuticals, the company behind one of these drugs, now says it’s building a giant database of human DNA information in what amounts to a large-scale, systematic search for the next PCSK9. At a new genetic research facility that Regeneron completed last month in Tarrytown, New York, the company says it has begun a five-year effort to sequence the genomes of as many as 100,000 volunteers recruited from East Coast hospitals and identify rare genetic outliers among them.