Our Physicians and Providers

Heng Wang, M.D., Ph.D.
Medical Director

A board-certified pediatrician and Fellow of the American Academy of Pediatrics (FAAP), Dr. Wang has served as our clinic’s Medical Director since our founding in 2002.

Born and raised in China, he became one of his country’s youngest physicians when he graduated from from Anhui Medical University in 1983 at age 20. He went on to become a laboratory researcher, and then earned a Ph.D. in biochemistry in 1992 from the University of Liege in Belgium. After emigrating to the U.S., he completed his postdoctoral training in nutrition and gastroenterology at Baylor College of Medicine in Texas and his residency in pediatrics at Arkansas Children’s Hospital in 2001.

It was by chance that one day Dr. Wang saw a recruitment ad in a pediatric journal; DDC Clinic was looking a medical director for its yet-to-be-built clinic. Intrigued by the opportunity to study rare diseases and treat children affected by them, he reached out to DDC Clinic. The rest, as they say, is history.

Since then, Dr. Wang has served more than 1,100 patient families. Today, he is internationally recognized for his expertise in more than 70 rare genetic disorders. As a physician-scientist with a passion for clinical research, Dr. Wang and his team have identified numerous novel genetic conditions, including ganglioside GM3 synthase deficiency, TMCO1 defect syndrome and SAMS association.

Dr. Wang has co-authored more than 80 scientific papers in reputable peer-reviewed journals, including Science, Nature Genetics, Proceedings of the National Academy of Sciences USA (PNAS) and Cell.

His work has been featured in the national and international press, including Associated Press, CBS 60 Minutes, Prosieben TV (Germany), New York Times, Boston Globe, Los Angeles Times, World Scientist, American Medical News (American Medical Association Weekly), and National Public Radio.

He received the 2006 American Academy of Pediatrics Special Achievement Award and the 2007 Johnson & Johnson Community Health Care Crystal Award. He was also the recipient of the 2007 Northern Ohio Live Award of Achievement in Health and Medicine and the 2007 Excellence Award in Community Service and Medicine from The United States Pan Asian Chamber of Commerce. In April 2014, he was featured in Science’s online version for his work at DDC Clinic.

Well respected by his peers in Northeast Ohio, Dr. Wang also serves as a faculty member at Case Western Reserve University and Cleveland Clinic.

Vincent Cruz, M.D., M.S., BSEE
Clinical Geneticist and Internal Medicine

Dr. Cruz joined our clinic in 2021, bringing a unique blend of internal medicine and genetics expertise. His commitment to patient care and research has significantly expanded our ability to provide comprehensive, personalized care.

Originally from Detroit, Dr. Cruz earned his Bachelor of Science in electrical engineering from the University of Michigan before pursuing advanced degrees in clinical research and medicine. His residency training in internal medicine and medical genetics at University Hospitals Center for Human Genetics solidified his foundation in these fields.

Dr. Cruz’s dual expertise has enabled us to offer continuity of care for our patients, ensuring a seamless transition as they grow and their needs evolve. He specializes in caring for adolescents and adults, providing highly personalized and comprehensive care tailored to their individual needs.

Dr. Cruz was drawn to our clinic by the opportunity to make a direct impact on individuals and our community. His passion for studying undiagnosed diseases and helping families find answers about rare conditions aligns perfectly with our mission.

As a physician-scientist with a background in engineering, Dr. Cruz is dedicated to advancing our understanding of medicine, particularly in the field of genetics. His unique perspective and dedication to research make him a valuable asset to our clinic.

John Tumbush, D.O.
Staff Physician

Dr. Tumbush is a graduate of the University of Toledo where he earned a Bachelor of Science in Pharmacy. He worked for three years as a Pharmacist at Cleveland Metro Hospital. Dr. Tumbush then attended Ohio University College of Osteopathic Medicine in 1988 and completed his residency in Family Practice in 1991 at Akron General Medical Center. Following his residency, Dr. Tumbush practiced medicine in Middlefield, Ohio for 32 years before joining DDC Clinic in May of 2024 where he will be practicing in the new Family Heart Center.

Dr. Tumbush has held many prestigious positions throughout his career. He was chief of staff at Geauga Community Hospital, President of the Geauga Medical Society, on the board for the Northern Ohio Academy of Medicine, and a board member of the Geauga Medical Center. He was chairman of the Geauga Community Hospital Medication Safety Committee for over 30 years and vice chairman of the System Wide Medication Safety Committee. He has been a member of the DDC Clinic Board of Directors since the clinic was founded.

Dr. Tumbush is a licensed pharmacist in the state of Ohio, board certified in Family Medicine, and a Fellow of the American Academy of Family Medicine. He was involved with the original research into MYBPC3 hypertrophic cardiomyopathy (HCM) and says he is excited to treat patients in DDC Clinic’s new Family Heart Center. Dr. Tumbush has been a Bureau for Children with Medical Handicaps (BCMH) provider since before DDC Clinic was founded.

Nicole Stevens, FNP, CRNP, DNP
Family Nurse Practitioner

Dr. Stevens is a nurse practitioner serving as our main provider at the DDC Clinic Pennsylvania Branch in Titusville. She is trained in family medicine and has experience in internal medicine, emergency medicine, dermatology, and long-term care. She received her Master of Science in Nursing and Family Nurse Practitioner degree at Carlow University in Pittsburgh, Pennsylvania in 2020. She completed a Doctor of Nursing Practice degree at Johns Hopkins University, researching newborn genetic screening practices in Northwestern Amish populations. Dr. Stevens was featured as a finalist of Johns Hopkins Empower your Pitch research communication competition for her presentation: A Screening for One, A Diagnosis for Many: The Implications of Newborn Genetic Screening for Amish Families. She is a current member of Sigma Theta Tau International Honor Society in Nursing and serves as PT faculty lecturer for Johns Hopkins graduate SON program Advance Pharmacology.

Before joining DDC Clinic, Dr. Stevens owned and operated a private practice which provided affordable health care to uninsured families. During that time, she worked closely with Amish families and began her relationship with our clinic working to diagnose and coordinate treatment for families with genetic disorders. At DDC Clinic Pennsylvania Branch, she engages in research, diagnosis, and management of genetic disorders affecting Pennsylvania and New York Plains communities.

“I’m honored to be a part of the DDC Clinic team and be the local resource for specialized care for Plain populations who are affected by genetic disease,” says Dr. Stevens.

Garrett Edinger, MS, CGC
Genetic Counselor

Garrett is a board-certified genetic counselor and recent graduate of the Case Western Reserve University School of Medicine Genetic Counseling Training Program. Garrett earned his Bachelor of Science degree in Biology from Eastern Nazarene College in Quincy, Massachusetts in 2020. Before starting graduate school, Garrett worked for the Indiana Department of Health during the COVID-19 pandemic. Garrett started off doing contact tracing for the Indiana Health Department, and later managed a team of workers as a part of the Indiana Health Department’s response to the pandemic.

Garrett joined DDC Clinic shortly after finishing graduate school in 2024. During training Garrett worked with patients and families at the Center for Human Genetics at University Hospitals Cleveland Medical Center. He also completed rotations at Cleveland Clinic, Akron Children’s Hospital and Metro-Health Medical Center. His graduate thesis work focused on how the genetic counseling profession is adapting to the growing number of treatments for genetic conditions using Sickle Cell disease as an example. Garrett is certified by the American Board of genetic counseling and is licensed to practice genetic counseling in Ohio, Michigan, and Pennsylvania.

As a genetic counselor, Garrett helps patients at DDC Clinic navigate the often-complicated results of genetic testing. Through careful analysis of a patient’s medical and family history, Garrett helps patients and families understand what genetic test results mean and their impacts on health. Garrett also works with our molecular diagnostics laboratory and outside laboratories to facilitate genetic testing for patients at DDC.

Garrett joined DDC Clinic because he was excited to work in a unique clinical setting: “DDC Clinic provides a great opportunity to serve patients and their families with rare genetic conditions. I’m excited about the opportunity to help our patients and families understand genetics.”