When Apple, Inc., cofounder Steve Jobs paid $100,000 to have his DNA sequenced in a bid to outrun the pancreatic cancer that ultimately claimed his life, he was just one of 20 people in the entire world to have had it done.
But for the general public, the benefits of DNA sequencing—which has been both timeconsuming and costly—have remained largely unattainable. Until now.
A new technology called next-generation sequencing (NGS), previously used in research studies but rarely for clinical diagnostic tests, is now being used in clinics affiliated with the University of Minnesota. It can test large numbers of very specific genes simultaneously and at a significantly reduced cost.
Already at the University of Minnesota Ataxia Center, NGS is helping clinicians diagnose dozens of forms of rare ataxias.
“The big technical advance is the capability of focusing the sequencing power,” says Matthew Bower, M.S., C.G.C., the Ataxia Center’s genetic counselor. “Rather than distributing it across 3 billion letters of the genome, you can focus it on a set of target genes.”
As Bower explains it, this targeting allows for a considerably shorter “diagnostic odyssey” for patients. In the past, diagnoses were ruled out one gene at a time, a process that for some patients would take decades. Using NGS, the process typically takes about two to three months.
NGS makes gene sequencing more accessible, too. The process once cost $1,000 to $2,000 per gene, and with tens of thousands genes in the human genome, the price was far out of reach for most people. But NGS typically costs between $1,500 and $4,000 total, Bower says, depending on how many genes are analyzed.
“We’re looking at hundreds of genes for the price of what it used to cost to look at a single gene,” he says.
Ataxia Center director Khalaf Bushara, M.D., says many of his patients are glad to have a definitive diagnosis, even if there’s no clear-cut treatment option. That’s particularly true if there’s a hereditary component to their disease, he says.
“They want to plan to have kids. Is it dominant or recessive?” he says. “Some patients just want to know.”
NGS is being used at other University-affiliated specialty clinics that treat patients for inherited genetic diseases and cancers, as well, says Bower, including the ophthalmology, otolaryngology, pediatrics, hematology-oncology, and blood and marrow transplant clinics.