Skip to main content

Leslie G. Biesecker, M.D.

Leslie G. Biesecker
Chief & Senior Investigator
Medical Genomics and Metabolic Genetics Branch

Clinical Genomics Section

B.S. University of California, Riverside, 1979
M.D. University of Illinois College of Medicine, 1983

T: (301) 402-2041
F: (301) 480-0353
Building 50, Room 5140
50 SOUTH DR, MSC 8004
BETHESDA, MD 20892-8004

Selected Publications

ClinSeq: A Large-Scale Medical Sequencing Clinical Research Pilot Study

Elements of Morphology: Human Malformation Terminology

DNA Identifications After the 9/11 World Trade Center Attack

Clinical Center Genomics Opportunity

YouTube videoNHGRI Pilot Project Uses Genomic Sequence Data to Do Predictive Medicine

Researchers in the Clinical Genomics Section study genomic variation as it relates to health and disease, applying this research to better understand rare disorders of development and growth, and to new clinical genomics approaches. The team's research goals are to improve medical care for affected patients, provide generalized knowledge about genetic disease and understand mechanisms of human development and physiology.

The group studies multiple anomaly syndromes, including Proteus syndrome and related mosaic overgrowth disorders and syndromic and non-syndromic polydactyly (additional fingers or toes). Patients with these disorders exhibit combinations of malformations, overgrowth, birthmarks and other manifestations. The section is an internationally recognized source of leadership in finding novel diagnostic and management approaches to these disorders and plans to use these discoveries to develop prospective treatments.

In order to find the genes that are altered in multiple anomaly syndromes, Dr. Biesecker's group uses massively-parallel sequencing to determine genotype-phenotype correlations-the connections between DNA sequence and physical manifestations. The team is actively recruiting patients for study protocols. Once enrolled, patients undergo extensive and sophisticated phenotypic assessments to understand the range and variability of these rare disorders.

In a second area of research, the group uses large-scale sequencing as a tool for clinical research. The ClinSeq® project enrolls both healthy and disease-affected patients; it had initially been focused on cardiovascular disease. Using massively parallel sequencing, the team has generated billions of base pairs of sequence, contributing to an understanding of rare versus common genetic variants in disease. The clinical focus of the ClinSeq® initiative has been expanded to include genes that cause cancer susceptibility, cardiac disorders and genetic responsiveness to medications. It is a leading effort in clinical genomics research and is helping researchers to establish new approaches for study design, informed consent and subject participation.


Dr. Biesecker is a clinical and molecular geneticist and is the chief of the Medical Genomics and Metabolic Genetics Branch at the National Human Genome Research Institute (NHGRI) of the National Institutes of Health. He uses genetic and genomic technologies to study the etiology of inherited disorders. He received his medical training at the University of Illinois, training in pediatrics at the University of Wisconsin, and in clinical and molecular genetics at the University of Michigan. His laboratory has elucidated the etiology and natural history of numerous diseases, including Proteus syndrome, PIK3CA-related overgrowth syndrome, TARP syndrome, oculofaciocardiodental syndrome, Lenz microphthalmia syndrome, McKusick-Kaufman syndrome, Bardet-Biedl syndrome, Pallister-Hall syndrome and Amish microcephaly, and has contributed to the discovery of many others. In addition, he developed the ClinSeq® program, which has consented more than 1,000 subjects for whole-genome sequencing with the interpretation and return of results. He co-directs a Clinical Laboratory Improvement Ammendments (CLIA)-certified molecular diagnostic laboratory within NHGRI.

Dr. Biesecker serves as an editor or board member for four biomedical journals, is an advisor to the Illumina Corporation and was a member of the board of directors for the American Society of Human Genetics. He served on advisory panels for the World Trade Center and Hurricane Katrina victim identification efforts. He was recently elected to the National Academy of Medicine of the National Academy of Sciences and has been elected to be the president of the American Society of Human Genetics for 2019. 

Scientific Summary

Top of page

Last Updated: November 1, 2017