Dr. Victor A. McKusick, a Johns Hopkins professor who pioneered the study of medical genetics and spent his career exploring how patients' genes predisposed them to medical disorders, died of cancer Tuesday at his home in Towson. He was 86.
Often referred to as the "father of medical genetics," Dr. McKusick was widely credited with helping establish the scientific link between inheritance and disease.
His meticulous research into rare genetic disorders - an intellectual pursuit he was discouraged from exploring as a young cardiologist - led to modern methods of classifying and treating inherited diseases.
"Today we lost a giant," Dr. Edward D. Miller, dean and chief executive officer of Johns Hopkins Medicine, said yesterday in a prepared statement. "He spent virtually all of his incredible career at Hopkins, but his influence and legacy reach around the world."
Dr. McKusick's life was spent studying genetic variation, but he entered the world in 1921 as a case of genetic similitude with an identical twin brother, Vincent. They grew up on a Maine dairy farm run by their parents, who were former school teachers.
He entered Tufts University in 1940, but ended his undergraduate studies early in 1943 to start at the Johns Hopkins University School of Medicine. He married Dr. Anne Bishop, another Hopkins physician, in 1949.
Dr. McKusick trained as a cardiologist and served as the executive chief of the cardiovascular unit at Baltimore Marine Hospital, but an encounter with a single patient altered the course of his career.
While examining a patient with Peutz-Jeghers syndrome, a rare inherited disease that puts patients at high risk of developing intestinal cancer and causes odd skin pigmentation, Dr. McKusick became curious about how a single genetic mutation led to problems in various organs.
He began carefully documenting the symptoms associated with another genetic disorder, Marfan syndrome, which causes people to develop unusually tall, lean bodies, along with heart defects and other abnormalities.
In the late 1950s, just a few years after DNA was discovered, he decided to devote his career to medical genetics.
"Some of my colleagues thought I was committing professional suicide because I had a reputation in cardiology and was shifting over to focus for the most part on rare, unimportant conditions, and so forth," Dr. McKusick said in an interview earlier this year.
