On the wall of Victor A. McKusick's office in Baltimore hangs a portrait of a sad-faced woman holding a six-fingered infant. The photograph, which he calls the Amish Madonna, was taken during McKusick's pioneering studies of the Old Order Amish of Pennsylvania 40 years ago. McKusick described genetic diseases in these and other patients long before there were tools to pinpoint the mistakes in their DNA.
McKusick is a white-haired, dark-suited figure, still vigorous and straight but, at 80 years old, slightly tremulous. Near the Amish Madonna portrait, he keeps a row of books holding the fruits of his patient and relentless efforts to place genetics in the mainstream of clinical medicine. First published in 1966 and now in its 12th edition, Mendelian Inheritance in Man is an ever-expanding catalog of human genes and the medical disorders associated with them. McKusick still oversees the compilation of the catalog that has earned him the honorific "father of medical genetics." His office is at the eponymous McKusick-Nathans Institute of Genetic Medicine, which is part of the Johns Hopkins School of Medicine, where McKusick has worked since World War II.
Some diseases are inherited in a recessive pattern, just as blue eyes are. Brown-eyed parents who each have a gene for brown eyes (B) and a gene for blue eyes (b) will have a blue-eyed baby if the child inherits both copies of b. Illustration by Dan Winters & Gary Tanhauser
McKusick became famous for linking genes to disease, but the slim single volume of the original Mendelian Inheritance in Man recorded no actual genes, although it described hundreds of genetic disorders. Their locations were unknown. The third edition reflects medical genetics in the early 1970s. "It recorded all the genes that had been mapped at that time," McKusick says with a smile. "It filled one page." During those early years, McKusick collected genetic disorders one by one, working alone at first and later assisted by staff and other associates. He culled the journals for rare conditions and wrote up his own observations. He watched as medical genetics grew from a research backwater into a hot spot of medical inquiry.
