Department of Genetic Medicine: Past and Present

At Johns Hopkins, basic science and clinical practice in genetics have had a productive partnership for more than 60 years. Pioneering work in the 1950s by Victor McKusick in the Department of Medicine and Barton Childs in the Department of Pediatrics led to the creation of two divisions of genetics at Johns Hopkins and helped lay the foundation of the then-novel field.


Working in the Moore Clinic, McKusick and his colleagues Edmond Murphy, Samuel Boyer and Reed Pyeritz provided for the first time robust clinical descriptions of genetic diseases, such as mucopolysaccharidoses, Marfan syndrome, homocystinuria and many skeletal dysplasias.

To organize the ever-growing body of knowledge on disorders and make it accessible to physicians around the world, McKusick created Mendelian Inheritance in Man, currently known as Online Mendelian Inheritance in Man, or OMIM. Simultaneously, in the Division of Pediatric Genetics, substantial contributions were being made by Childs and Barbara Migeon on X chromosome inactivation, by Neil Holtzman on biochemical genetics, and by Michael Kabak and George Thomas on genetic screening tests for Tay-Sachs disease and on lysosomal disorders. Also at that time, Haig Kazazian, Stylianos Antonarakis and Gregg Semenza explored molecular causes of hemoglobinopathies, hemophilia and regulation of heomoglobin levels. 

In 1980, Migeon founded the Human Genetics Graduate Program, which continues to this day and has produced more than 300 Ph.D.s, nearly all of whom are prominent investigators.

In 1988, the two genetic divisions were joined physically and administratively to form the Center for Medical Genetics under the direction of Kazazian. The center was home to an active clinical genetics service and fostered continued research by leaders in the field, such as Samuel Boyer, Kirby Smith, Hal Dietz, Ethylin Jabs and David Valle.

At the same time, Dan Nathans, Ham Smith, Tom Kelly and others were conducting groundbreaking basic research within Johns Hopkins’ Department of Molecular Biology and Genetics, including the Nobel Prize-winning discovery of restriction enzymes. Collaborations between the medical geneticists and the basic scientists were key to many advances made at Johns Hopkins.

Formation of the Institute of Genetic Medicine

In 1999, the Johns Hopkins University School of Medicine formed the McKusick-Nathans Institute of Genetic Medicine. The name honored two early leaders in the field and emphasized translation of advances in genetics, molecular genetics and genomics to clinical medicine. 

Beginning in September 2000, Aravinda Chakravarti served as inaugural director of the Institute of Genetic Medicine, where he expanded human genetics activities at Johns Hopkins in areas such as quantitative genetics, genomics and common complex traits.

In 2015, the Institute of Genetic Medicine and the Department of Pathology launched Johns Hopkins Genomics, which integrates CIDR, DDL, segments of GRCF, a new CLIA/CAP-approved clinical whole exome sequencing service and the Molecular Diagnostic Lab (MDL). The MDL provides a large fraction of the clinical molecular testing for the Johns Hopkins Kimmel Cancer Center.

Under the leadership of David Valle, the institute reached a new distinction in 2019 with the formation of the McKusick-Nathans Institute of Genetic Medicine | Department of Genetic Medicine


World renowned geneticist Ambroise Wonkam now serves as the director of the Department of Genetic Medicine and the McKusick-Nathans Institute of Genetic Medicine. An advocate of diversifying the pool of genetic reference data that scientists often use to make genetic discoveries, Wonkam has made pivotal contributions to research on sickle cell disease, hearing loss, medical research ethics and genetics education. 

Department of Genetic Medicine research includes finding the molecular bases of single-gene, or Mendelian, disorders; identifying the genes that influence complex traits, such as coronary artery disease; studying the genes and proteins that regulate whether genes are turned on or off; computational biology; molecular biology; developmental genetics; and proteomics. The Department of Genetic Medicine is also home to a number of research cores and services. These include the Genetics Resources Core Facility (GRCF), the Center for Inherited Disease Research (CIDR), the Finzcenter Zebrafish Core Center and the DNA Diagnostic Lab (DDL).

Ada Hamosh is the Department of Genetic Medicine’s clinical director and oversees its clinical activities, including multiple outpatient clinics, an inpatient service and an active consult service. Clinics include the Epigenetics and Chromatin Clinic, which treats patients with disorders of the machinery that packages DNA and regulates it via chemical “tags”; the Cardiovascular Connective Tissue Disorder Clinic; and the Greenberg Center for Skeletal Dysplasias, which specializes in bone conditions, such as those that cause short stature.

Finally, the Department of Genetic Medicine is actively involved in medical student, graduate student, resident and postdoctoral education programs.