By Sharon Gray
(October 1, 1998)
Geneticists at the Faculty of Medicine had an exciting few days in September when the father of medical genetics, Dr. Victor A. McKusick, came back to Memorial. As the second guest speaker in the faculty's 30th anniversary lecture series, he presented an overview of the development of medical genetics and also took the time to meet with colleagues and discuss ongoing research in Newfoundland.
Dr. McKusick has a long association with this university. He was a member of the selection committee for the first faculty members of the medical school back in 1967, and in 1979 he received an honourary degree from Memorial. During his three-day visit last month with his rheumatologist wife, Dr. Anne McKusick, he gave two lectures and spent a morning discussing case histories with the Genetics Group.
Dr. McKusick founded an entire branch of medicine that didn't exist when he graduated from the Johns Hopkins University School of Medicine in 1946. He originally trained in cardiology but became fascinated with scientific discoveries that proved DNA is the substance that transmits hereditary information from cell to cell. He began to explore patterns of inheritance among patients with connective disorders and wrote a definitive book on the subject in 1956.
It was also in 1956 that the correct number of human chromosomes -- 46 -- was identified. By 1959 the extra chromosome in Down Syndrome was discovered. "Now that researchers could actually see a chromosome and determine its defect, there was an anatomical base for medical genetics," said Dr. McKusick, who has spent his entire career at Johns Hopkins University.
It wasn't until 1968 that specific genes on autosomal chromosomes were identified. In 1980, molecular genetics entered the field and by 1986, 750 genes had been mapped. And now the Human Genome Project expects to map all human genes -- estimated at about 80,000 -- by the year 2005.
The explosive growth in medical genetics was graphically illustrated by Dr. McKusick in a slide of all 12 editions of his book Mendelian Inheritance in Man, first published in 1966. From a slim volume listing about 1,500 phenotypes which were presumed to represent the manifestation of a gene in each case, this publication has grown to three fat volumes holding the clues to 9,000 genes.
Mendelian Inheritance in Man -- now available on-line with 9,700 entries -- is like a phone book with names and addresses. It led Dr. McKusick quite naturally to the idea of taking it further and producing a human gene map that would show not only which genes reside on which chromosomes, but precisely where they are located. In 1973 he and colleagues organized the first of what was to become a regular series of Human Gene Mapping Workshops and he was a leading proponent of the now famous Human Genome Project.