|Dr. David L. Valle
Traditionally, medical school training has emphasized
appropriate treatments for the average patient. Yet, experienced physicians know that each patient is unique, with distinct responses to treatment and varying complications.
Dr. David L. Valle, director of the McKusick-Nathans Institute of Genomic Medicine at Johns Hopkins University, explored this paradox from the genomic perspective
as the first speaker
in a 7-lecture series, Genomics in Medicine, held recently at Suburban
Hospital. The lectures, which will be held monthly through July, are sponsored by the National Human Genome Research Institute,
in collaboration with Suburban and Johns Hopkins University
School of Medicine.
“We have an opportunity to move medicine from a very successful level to a new plateau,” Valle said. “I think the way we will do that is by individualizing
Valle participated in the Human Genome Project, completed in 2003, and continues to discover surprising
insights from the genome. Once the reference
human genome was decoded, researchers turned their attention to understanding genetic variation. They created a map of common variations
in the human genome based on haplotypes, which are blocks of genetic variants inherited together. The HapMap was completed in 2005.
Since then, advances in understanding human variation have progressed with the 1,000 Genomes Project. The goal of this current effort is to compile the genomes of 2,500 individuals from around the world and to catalog at least 90 percent
of the most common genetic variations.
“We can look forward to having a pretty good handle
on all the genetic variations we have in common,”
Valle said. “We will continue to find rare [genetic] variation going forward.”
Valle will contribute to this effort as principal investigator on a recently announced rare disease project. NHGRI has awarded $16 million to three institutions to sequence thousands of genomes of people with rare disorders. The project’s goal is to identify genetic variants responsible for rare disorders, facilitate rapid and accurate diagnosis of such disorders and, eventually, develop new therapeutic approaches.
Such a goal is possible due to declining costs in sequencing and faster sequencing
speeds, Valle said. The cost of sequencing 1 million high-quality DNA base pairs has steadily declined, from $10,000 in the year 2000, to $1 in 2011. Faster sequencing speeds mean that in 2011, 30,000 human genomes were sequenced and will be available in databases, as opposed to 2010, when only 25 to 30 human genomes were sequenced and available.
The wave of progress will affect how doctors treat disorders and prescribe drug therapies, said Valle, particularly regarding drug dose and response. Individualized
medicine has already determined some cancer treatments. For example, acute lymphoblastic leukemia, the most common form of childhood cancer, is cured in the great majority of children using currently available medications, but there are serious side effects. Researchers are now studying how to reduce these effects by better understanding genetic variations responsible for drug metabolism
For more information about the Genomics in Medicine lecture series, visit www.genome.gov/27546022.