The incredible speed at which research into the human genome has recently progressed has led to the widespread use of genomic data in clinical settings. The day will soon come when clinical practice that fails to utilize patients' genomic data will be considered outdated and will pose a high risk of legal action. In this lecture, I discuss several topics: 1.the progress of human genomic research, 2. Homo sapiens as just one of the many species on Earth; 3. the clinical applications of genomic research findings, with Kawasaki disease as an example;and 4.the current state of genomic research and its future prospects.
Medical researchers and doctors have long dreamed of a day when health care services based on each individual's genomic data will be a reality;this is usually referred to as “madeto-order medicine,” “tailor-made medicine,” “personalized medicine,” and most recently, “precision medicine.” Thanks to the recent rapid development of genomic analysis,such as next-generation sequencing,as well as that of statistical analysis methods, it has been said that individual genomic data were available at a cost as low as$1,000 in 2014.
Our planet is 4.6 billion years old, and life began 3.8 billion years ago. Since then,the Earth has witnessed the evolution of prokaryotic and eukaryotic unicellular organisms, followed by multicellular organisms, photosynthetic plants, the Cambrian explosion of marine life, and the emergence of land-dwelling creatures. Our mammalian ancestors appeared during the age of the dinosaurs, which suffered a mass extinction due to a dramatic change in climate caused by an asteroid impact. The small dinosaurs that survived evolved into today's birds while the mammals of that era evolved to successfully occupy a diverse array of ecological niches. The human family appeared about 2.5 million years ago in Africa. Archaic humans, such as Homo neanderthalensis, lived among our Homo sapiens ancestors, who appeared about 200,000 years ago. Now we know that 21%of the human genome has genes in common with prokaryotes and other eukaryotes. The difference between our genome and that of the gorilla and the chimpanzee is only 2% and 1%, respectively. Among Homo sapiens, the difference between any two individuals is only 0.2%, which manifests as differences in skin color, disease susceptibility, and other traits.
Kawasaki disease was identified by Dr.Tomisaku Kawasaki, who reported his findings in 1967. Since then, vigorous efforts have been made to identify the cause of the disease, but so far, nothing specific has been found. We therefore took a genome-based approach and identified several genes responsible for the development of Kawasaki disease. Because some of the identified genes are thought to participate in the Ca2+-NFAT signal transduction pathway, we hypothesized that cyclosporine A, which is known as a suppressor of this pathway, might be useful in the treatment of the disease. We performed an investigator-initiated clinical trial and confirmed our hypothesis. This was one of the first clinical applications based on human genome research.
Now, there are several large-scale genome-based projects, such as the UK Biobank, that are open to any researcher who would like to make use of their resources. They also contain clinical information and patient data, such as socioeconomic status, and educational background. With these kinds of resources at our disposal, we can expect great accomplishments in the not-too-distant future.