David Weaver started in the field of genetics decades before the Human Genome Project mapped the DNA code for human life. There was little known about what genes do and what happens when they are defective.
“Back in the 1950s,” said Weaver, MD, MS, recalling his early career explorations as a student at the College of Idaho, “there was basically little in the field of human genetics.”
This year marks Weaver’s 50th anniversary on the faculty at the Indiana University School of Medicine, where he is a professor emeritus of medical and molecular genetics and of pediatrics. Starting in 1976, Weaver built the clinical genetics program within the Department of Medical and Molecular Genetics and led that division for nearly 30 years.
“We started with three people,” recalled Weaver. “Now our division has over 80.”
That expansion translates into hundreds of Indiana families finding answers and a path forward through diagnosis and treatment of inherited disorders.
“Dr. Weaver led the clinical division during the period of rapid expansion of syndrome identification and definition, gene mapping and identification, the discovery of maternal inheritance of mitochondrial DNA, and the completion of the Human Genome Project, to name a few of the remarkable advances during his tenure,” said Stephanie Ware, MD, PhD, chair of the Department of Medical and Molecular Genetics. “He has been recognized as a master clinician and a consummate educator.”
One of those impacted by Weaver’s teaching was Tatiana Foroud, PhD, a statistical geneticist who is now executive associate dean for research affairs at the IU School of Medicine. When she was a graduate student, Weaver’s clinical genetics course was one of her favorites. As a researcher focused on analysis and laboratory experiments, it helped Foroud connect her work to the real-world issues of living with genetic diseases.
“The humanity of what I do and the impact it can have on a family has stayed with me my entire life,” said Foroud.
Today, at 87 years old, Weaver can still be found teaching medical residents and seeing patients at IU Health genetics clinics at Riley Hospital for Children. Through the years, he has trained generations of physicians, medical students, genetic counselors, nurses and others in the field of clinical genetics.
It all started with his own training under pioneers in medical genetics during the 1960s and ’70s. During one of Weaver’s early clinical experiences, he and colleagues were the first to define a rare genetic disorder causing dysmorphic facial features and accelerated physical growth, now known as Weaver syndrome. Later, he was part of the team that discovered the condition’s cause: a mutation in the EZH2 gene.
“David Weaver began his career in medical genetics just as it was becoming a specialty, and he has been one of its pioneers,” said Ware.
“He is a giant in our field,” said Foroud.
From Idaho to Indiana
Growing up in south-central Idaho, an area known for its potato production, Weaver did his share of picking potatoes and never imagined a career in human genetics. Although his father, grandfather and uncle were general practice physicians, he early on aspired to be a heart surgeon “because open-heart surgery had just been accomplished and was an exciting area in medicine.”
Weaver majored in zoology at the College of Idaho, located near Boise, and developed an interest in research. His most fascinating project was an unsuccessful attempt to breed kangaroo rats, a desert species related to gophers, which would make excellent research animals but for one thing: they refuse to breed in captivity.
His lifetime career interest in genetics began with a single course in the subject during his senior year of college. After graduation, he was admitted to the University of Oregon School of Medicine, where he entered a dual degree program, alternating medical studies with research. His project explored how genetic changes associated with Down syndrome affected the activity of an important enzyme in white blood cells.
After a general medical internship in Milwaukee, Wisconsin, Weaver was commissioned into the U.S. Public Health Service and was assigned to the Arctic Health Research Center on the campus of the University of Alaska in Fairbanks. There he worked with a biochemist on unique medical conditions found within the native Alaskan population.
Although he and his wife endured winter’s near-total darkness and temperatures that dipped as low as -69 F, they also enjoyed the endless days of sunny Alaskan summers. After three years at that post, they returned to Oregon, where Weaver began his pediatric training, shifting his focus from research to treating patients.
During his first year of his residency, Weaver saw a patient named Stephen who had dysmorphic facial features and other symptoms indicating a congenital syndrome. He referred Stephen to a specialist in Seattle, David Smith, MD, the founder of the field of dysmorphology, which studies birth defects and structural anomalies. Disappointingly, Smith could not identify the boy’s syndrome.
After residency, Weaver joined Smith in Seattle to do a fellowship in human genetics. “Because of Dr. Smith’s charisma and enthusiasm, and the fascinating dysmorphology I saw, I became enamored with dysmorphology,” Weaver recalled in a short autobiography he wrote in 2022.
One day when Weaver was in training in Seattle, a local boy was brought to one of Smith’s clinics with a dysmorphic condition that matched Stephen’s characteristics. Weaver and Smith subsequently studied these two patients, who appeared to possess a new genetic syndrome. They published these two cases in the Journal of Pediatrics in 1974. Weaver syndrome, as it is now known, is a rare genetic disorder characterized by rapid growth and bone maturation, distinctive facial features, and muscle and joint issues.
During his time in Seattle, Weaver also worked with an expert in skeletal dysplasia, an area covering a spectrum of genetic disorders affecting bone development and growth. Weaver also took a second fellowship at the University of Oregon School of Medicine, where he primarily studied pediatric metabolic disorders.
“The fascination of genetics is it’s not one or a few disorders,” Weaver said. “One can see and study literally thousands of different conditions, and involvement with every organ system. So it’s a very broad spectrum.”
When it came time to look for his first faculty position, the opportunity at Indiana University stood out: “The position was incredible for me since it was in a well-established and funded program with considerable opportunity for clinical expansion and teaching.”
Weaver’s enduring impact
During his 50 years at IU, Weaver has conducted hundreds of medical genetics and skeletal dysplasia clinics, including being the medical director for Indiana’s first clinic dedicated to diagnosing and treating Marfan syndrome at Riley Hospital for Children. He also has served as medical advisor for the Indiana chapter of Little People of America, as well as dozens of other nonprofit and governmental advisory boards and committees over the years.
Under Weaver’s 29-year leadership, the Division of Clinical Genetics expanded from just one half-day clinic weekly to four additional clinics focused on genetic counseling, hereditary cancer, fetal alcohol syndrome and long-term follow ups. The division also established six outreach clinics around the state — from South Bend to Evansville. The department now holds over 40 clinics during the average week. In 1992, he initiated the genetic counseling training program in the department, which has since produced over 200 IU-trained genetic counselors.
Weaver’s mentees over the years have included several change-makers in the field, including Merlin Butler, MD, PhD, an IU-trained clinical geneticist and prolific researcher who has published over 400 articles, and Cynthia Moore, MD, PhD, who went on to direct the CDC’s division for congenital disorders.
Since stepping down as division director in 2005, Weaver has continued teaching and caring for patients for an additional 21 years. During his 50 years at IU, he has been a prolific publisher who has authored or coauthored over 150 refereed articles, 35 book chapters and a book on prenatal diagnosis with two subsequent editions. He continues to publish even today.
“His contributions to the field cannot be fully calculated,” said Ware, “but he has touched the lives of countless patients, families, trainees and colleagues with his knowledge, dedication and wit.”
