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James R. Priest, MD

Assistant Professor of Pediatric Cardiology

Portrait of James R. Priest

After growing up (mostly) in Oregon, James graduated from Oberlin College and Conservatory with a BA in Biology, recieving the highest honors, and a B.Music degree, which he pursued thanks to his passion for playing the French horn. James then attended Berkeley for graduate school (MA) and Stanford for medical school (MD). His clinical training was at the University of Washington in Pediatrics, and at Stanford in Pediatric Cardiology. James brings a unique understanding of clinical application to his research approach. In his free time, James enjoys spending time with his family, cooking, reading, and doing almost anything outside—usually doing at least two of these things in combination.



Research Interests Include

  • Influence of maternal glucose metabolism on fetal cardiac development
  • Genetic basis of Congenital Heart Disease and long-term outcomes
  • Application of clinical sequencing and genetic testing

Catherine Tcheandjieu, DVM/PhD

Postdoctoral Scholar

Portrait of Catherine Tcheandjieu

Catherine initially studied veterinary medicine and received her veterinary degree from the School of Veterinary Medicine in Alger (Algeria). She then decide to continue into research in genetics epidemiology, and she received her PhD from the University of Paris Saclay in France. While there, she studied the role of several polymorphisms, susceptibility genes, and copy number variations (GSTM1 and GSTT1) in differentiated thyroid cancer among Europeans and Melanesians. To do this, she used fine-mappping and pathways approaches. She also studied the interactions between genetic risk factors and alcohol consumption, smoking, body mass index, obesity, and hormonal and reproductive factors. Her current postdoc project in the Priest Lab is focused on studying the pleiotropic effects of genes involved in different syndromic diseases with Congenital Heart Diseases-related phenotypes - such as Alagille syndrome, a syndrome associated with major cardiac malformation - using Phenome Wide Association Studies in a large genomic dataset from the UK (the UK biobank). She also aims to study the parental contribution of genetic risk factors for diabetes and diabetes related traits in congenital heart disease in the offspring of non-CHD affected parents using the Pediatric Cardiology Genomic Consortium (PCGC).

John Gorzynski, DVM

Doctoral Candidate

Portrait of John Gorzynski

As an undergraduate, John studied biology. He then continued on to veterinary school where he received a DVM. During his time at university, John investigated the effects that antiviral drugs have on retroviruses in relation to the development of resistance. He then switched his research focus in veterinary school to investigate genetic variations related to structural heart disease in captive chimpanzees. John then transitioned to the clinic as a mixed animal veterinary surgeon, treating animals ranging in size from mice to horses, with a lot of dogs, cats, and cows in between. While he enjoyed his time as a veterinarian, he often found himself thinking of how to further investigate cardiomyopathies in great apes. This interest led John back to an academic life, where he is now a graduate student at Stanford seeking his PhD. When not in the lab or the clinic, John enjoys running ultra-marathons, skiing, and scuba diving.

Melissa Slocumb, MS

Research Professional

Portrait of Melissa Slocumb

Melissa studied neuroscience (BS) and graduated with honors from the University of Nevada, Reno. She then earned her masters in biology from Florida Atlantic University, where her research with fruit flies allowed her to combine genetics with metabolic and behavioral outputs to learn how sleep and metabolism are integrated. Melissa is currently working to determine mechanistic causes of congenital heart disease by characterizing disease-associated genetic varients and looking at how maternal glucose effects the developing heart. In her free time, Melissa enjoys teaching, playing soccer, and going to concerts with friends.


Heliodoro Tejeda Lemus, BS

Research Data Analyst

Portrait of Helio Tejeda

Helio attended the University of California Irvine (UCI) where he began his undergraduate career in Mathematics. As an undergraduate, he participated in UCI’s Interdisciplinary Computational and Applied Mathematics Program (iCAMP), a summer research program where he focused on Game Analysis (Black Box: The Ultimate Game of Hide and Seek). It was his work on this project that prompted Helio to shift his concentration from Mathematics to Computer Science. He graduated from UC Irvine in 2017 with a major in Computer Science specializing in Intelligent Systems and a minor in Mathematics. Before coming to Stanford, he worked as a Data Analyst where he applied software engineering techniques to build automated data systems. In the Priest Lab, Helio is using his background in Computer Science to apply Computer Vision, Image Processing, and other Machine Learning technologies for the classification and segmentation of Cardiovascular MRI data. Helio plans to return to school and pursue a Doctorate in Computer Science and Cognitive Science.

Mengyao "Moya" Yu, PhD

Postdoctoral Scholar, Data Scientist

Portrait of Mengyao Yu

Moya received her PhD from Paris Descartes University in France. She studied the genetics of mitral valve prolapse (MVP) with the aim to better understand the genomic basis of MVP and elucidate the biological mechanisms behind the genetic association. By applying pathway-based approaches and fine-mapping, she was able to identify several interesting candidate genes for MVP. Her current interest in the Priest Lab is to investigate the genomic basis of congenital heart disease and long-term outcomes using data from the Pediatric Cardiology Genomic Consortium. In addition, meta-analyses are applied in several other cohorts to improve the study, such as the UK Biobank and Cordell. In her spare time, Moya enjoys spending time with her family, cooking, and doing outdoor activities.



Emmi Helle, MD, PhD

Postdoctoral Fellow

Photo of Emmi Helle pipetting in the lab

Emmi worked as a postdoctoral scholar in the Department of Cardiovascular Medicine at Stanford University from 2015-2017. She received her MSc. (Econ.) degree from Turku School of Economics in Finland, her MD degree from Linköping University in Sweden, and her PhD from Turku University, Finland. Her research interests include genetic and environmental origins of congenital heart disease, and using patient derived induced pluripotent stem (iPS) cells in cardiovascular disease modeling. She is currently finishing her residency in pediatrics in Helsinki University Children’s Hospital and continuing her research as a postdoctoral fellow in the Kivelä lab, University of Helsinki, Finland.

Subhash Juneja, BSc, MSc, PhD

Life Science Research Professional II

Portrait of Subhash Juneja

Subhash did his PhD in Animal Biochemistry in India and has worked at the Mayo Clinic in Rochester, MN; the Hospital for Sick Children at Toronto, University; the Health Network at Toronto, Canada; and McGill University in Montreal, Canada. His research has been in developmental biology, regenerative medicine, and stem cells. During 2017, Subhash worked in the Priest lab as a Life Science Research Professional II and helped to establish a new wet lab for Dr. Priest. He also contributed to a research project investigating how maternal diabetic conditions may cause congenital heart problems using mouse embryonic hearts in an ex vivo model. Currently, Subhash is a research consultant for a private company in Toronto, Canada, and he is learning how to design websites.

Ke Xiao, MSE

Research Data Analyst

Photo of Ke Xiao hiking in Zion National Park

Ke studied Mechanical Engineering at Beihang University (Beijing, China). Then he graduated from the Colorado School of Mines with a masters degree, during which time his research was focused on Robotics and Computer Vision. Ke then joined the Priest lab as a Research Data Analyst, where he applied computer vision, image processing, neural networks, and other machine learning technologies to cardiac MRI data for the purposes of classification, segmentation, and the automatic generation of various heart measurements. Ke's work with the Priest Lab continues, though he has recently moved on to start his Ph.D.

Priyanka Saha, BS

Research Fellow

Photo of Priya Saha hiking

Priya excelled as part of the Priest Lab when she joined us as a Sarnoff Cardiovascular Research Foundation Fellow in 2017-2018. While here, she honed her programing skills and used large data analysis techniques to identify genetic factors contributing to heart diseases. After contributing to some publications, Priya returned to finish her 4th year of medical school at Harvard Medical. Priya has learned that she will be returning to her home town for her residency at the University of Washington Affilliated Hospitals for Pediatrics in Seattle. She has hopes of becoming a pediatric cardiologist.

Aldo Cordova Palomera, PhD

Postdoctoral Scholar, Data Scientist

Portrait of Aldo Cordova Palomera

Aldo did his Ph.D. training at the University of Barcelona (Spain). He then had an internship at UMC Utrecth (Netherlands), and later he was a postdoctoral fellow at Oslo University Hospital (Norway). His interest in molecular genetics led him to become a postdoctroal scholar in the Priest Lab, where he further developed his skills in applied statistical methods for population genetics and related topics, with a focus on congenital heart disease. After two years, Aldo has decided to move his career away from academia, and he now resides in San Diego as a data scientist for Takeda Pharmaceuticals.

Matthew Aguirre, AB

Research Data Analyst

Portrait of Matthew Aguirre

Matt received his degree in Applied Mathematics (AB) at Harvard College. His past research includes developing machine learning methods for sequencing data validation at the Broad Institute, and building graphical models of infectious disease transmission at the Program for Evolutionary Dynamics at Harvard. In the Priest Lab, Matt researched genetic risk models for congenital heart disease, focusing on aggregated genetic effects and structural variation. Outside the lab, Matt can be found exploring nature, talking politics, or playing the blues on a stray piano. Matt is now conducting his PhD work at another lab at Stanford University.

Praneetha Potiny, BS

Data Operations Specialist

Portrait of Praneetha Potiny

Praneetha went to UC Santa Cruz and received her degree in Cognitive Science (BS) with an emphasis in Human-Computer Interaction and a minor in Computer Science. Post-graduation, she worked for an SEO company where she gained professional working experience in data analyses and data visualization. Praneetha joined the Priest Lab to explore different kinds of research. While here, she contributed to publications and primarily used data wrangling techniques to create manageable datasets for other researchers in the lab. Now, Praneetha is applying her skills at NinthDecimal Marketing and Advertising. In her free time, you can find Praneetha relaxing with a cup of tea.

Josephine Krieger

Undergraduate Research Assistant

Portrait of Josephine Krieger

Josephine grew up in Cleveland, OH and in Copenhagen, Denmark. She is part of Stanford’s Class of 2021 and is majoring in Biology. Since joining the lab in January 2019, she has been working with Melissa to investigate the genetic basis of congenital heart disease, as well as the effects of maternal glucose metabolism on fetal heart development. Josephine has moved in to continue her work on the heart in Kristy Red-Horse's lab at Stanford University, where she intends to write her honors thesis. She is also thinking about pursuing medical school in the future. In her free time, Josephine enjoys dancing, hiking, and going to the movies.