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.
David L. Valle, M.D., 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 seven-lecture series, Genomics in Medicine, held Dec. 2, 2011, at Suburban Hospital, in Bethesda, Md. The lectures, which will be held monthly through July 2012, are sponsored by the National Human Genome Research Institute (NHGRI), in collaboration with Suburban Hospital and the Johns Hopkins University School of Medicine.
"We have an opportunity to move medicine from a very successful level to a new plateau," Dr. Valle said. "I think the way we will do that is by individualizing medical care."
Dr. Valle actively participated in research for the Human Genome Project, completed in 2003, and continues to discover surprising insights from the genome. A genome sequence plots the order in which the DNA molecule is organized in living organisms. The human genome is comprised of 3.2 billion nucleotide bases that have a particular order and provides the instructions for the form and function of the cells of our body.
According to Dr. Valle, once the reference human genome was decoded, researchers turned their attention to understanding genetic variation in the genome. Towards that end, researchers created a map of common variations in the human genome based on haplotypes, which are blocks of genetic variants inherited together. The HapMap (www.genome.gov/11511175/About-the-International-HapMap-Project-Fact-Sheet) was completed in 2005.
Since then, advances in understanding human variation have progressed with the 1000 Genomes Project (www.genome.gov/27528684/1000-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," Dr. Valle said. "We will continue to find rare [genetic]variation going forward."
Dr. Valle will contribute to this effort as the principal investigator on a recently announced rare disease project. In December, NHGRI awarded $16 million to three institutions to sequence thousands of genomes of people with rare disorders (www.genome.gov/27546261/2011-Release-NHGRI-broadens-sequencing-program-focus-on-inherited-diseases-medical-applications). The project's overall goal is to identify genetic variants responsible for the rare disorders, facilitate the rapid and accurate diagnosis of rare disorders and, eventually, develop new therapeutic approaches.
Such a goal is possible due to declining costs in sequencing and faster sequencing speeds, Dr. Valle said. The cost of sequencing a million high quality DNA base pairs has steadily declined, from $10,000 in the year2000, to $1 in 2011. Faster sequencing speeds mean that in 2011, 30,000 human genomes will be sequenced and available in databases, as opposed to 2010, when only 25 to 30 human genomes were sequenced and available.
The wave of genomic progress will impact how doctors treat disorders and prescribe drug therapies, according to Dr. Valle, particularly regarding drug dose and response. Individualized medicine has already impacted 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 the drugs' side effects by better understanding the genetic variations responsible for drug metabolism and response.
The next two talks in the Genomics in Medicine lecture series focus on breast cancer. In January, NHGRI's Genome Technology Branch Chief Lawrence Brody, Ph.D., will present: "An introduction to genomics: breast cancer genes, risk assessment and screening." Dr. Brody will explain how the makeup of a woman's genes is the strongest (but not only) determinant influencing her risk of breast cancer. Then, in February, Stanley Lipkowitz, M.D., Ph.D., from the National Cancer Institute's Laboratory of Cellular and Molecular Biology,, will present: "An introduction to genomics: breast cancer diagnosis and treatment."
For more information about the Genomics in Medicine lecture series, please go to: www.genome.gov/27546022/20112012-Genomics-in-Medicine-Lecture-Series
Advanced registration is not required; however, those requesting continuing medical education (CME) credits are asked to sign in on-site.
Last Updated: December 22, 2012