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.

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, DNP, CRNP, FNP
Family Nurse Practitioner

Dr. Nicole Stevens is a Family Nurse Practitioner and the primary provider at the DDC Clinic for Special Needs Children Pennsylvania Branch in Titusville, Pennsylvania. She has more than a decade of clinical experience in family and internal medicine, emergency medicine, dermatology, geriatrics, and long-term care, with a specialized focus on genetic medicine and rare genetic disorders.

Dr. Stevens earned her Master of Science in Nursing and Family Nurse Practitioner degree from Carlow University and her Doctor of Nursing Practice from Johns Hopkins University, where her doctoral research focused on newborn genetic screening practices among Amish populations in Northwestern Pennsylvania. She also serves as part-time faculty in the Johns Hopkins School of Nursing graduate program, teaching Advanced Pharmacology and mentoring future nurse practitioners.

Prior to joining DDC Clinic, Dr. Stevens owned and operated a private practice providing affordable healthcare to uninsured families. Through her work with Amish families, she developed a strong interest in genetic disorders and began collaborating with DDC Clinic to coordinate care for affected families.

At DDC Clinic Pennsylvania, Dr. Stevens provides diagnosis and management of genetic disorders and supports research involving Plain communities throughout Pennsylvania and New York. She is honored to serve as a local resource for specialized genetic care and to help improve access to comprehensive, patient-centered care for families affected by genetic disease.

Kyle Whittemore, PA-C
Physician Assistant

Kyle Whittemore graduated from Baldwin Wallace University in Berea, Ohio, with a Master of Medical Science Physician Assistant Program degree. He also completed a bachelor of Science in Chemistry from Lake Erie College in Painesville, Ohio, where he received awards for Excellence in Research as well as Excellence in Chemistry.

Prior to earning his degrees, Kyle served 11 years in the armed forces. In 2008, he joined the U.S. Army Reserves, where he was trained as a combat medic. He was sent to Honduras, where he trained their local military on how to medically provide for their citizens. While in the Reserves, he was also trained in medical emergencies through the volunteer fire department on which he served.

Due to an increasing desire to serve, he became a full-time soldier in 2012, obtaining advanced training in anesthesia, battlefield surgery, microbiology, and critical care in field conditions as well as hospitals and clinical settings. The goal of the position was to allow Kyle to be able to serve anyone from anywhere in the world and be able to provide great medical care for the various needs they may have. This experience taught him that limited resources and accessibility should never exempt someone from quality care.

After being retired from the military in 2019, Kyle sought further education to become a better and more qualified provider for the community in which he lives. During his rotations, in his graduate program, and through his previous experience, Kyle knew that he wanted to work with families and provide quality care to each and every patient he was blessed to serve.

“I’m honored and feel privileged to be part of the DDC Clinic team. I’m thoroughly impressed by DDC Clinic’s mission and execution. It’s something I want to be a part of,” says Kyle. “As Isaiah 6:8 says ‘And I heard the voice of the Lord saying “whom shall I send, and who will go for us?” Then I said, “Here I am! Send me.”’

Mollie Cochran, MS, CGC
Genetic Counselor

Mollie Cochran is a certified genetic counselor at the DDC Clinic, where she provides genetic counseling services for patients and families affected by inherited conditions. She is trained across a range of specialties, including pediatric, cardiovascular, neurological, metabolic, and general adult genetics. In her role, Mollie supports patients through the genetic testing process, helping them understand complex information and make informed decisions about their care.

Mollie earned her Master of Science in Human Genetics and Genetic Counseling from Thomas Jefferson University. She also holds a Bachelor of Science in Biology with a minor in Psychology from Allegheny College. During her undergraduate studies, she received the Biology Faculty Award for the highest academic average among biology majors and was a distinguished Doane Scholar.

Originally from Northwestern Pennsylvania, Mollie was drawn to genetic counseling by a desire to better understand the root causes of medical concerns and to build meaningful relationships with her patients. She is passionate about providing compassionate, individualized care that reflects each patient’s values and goals.

In addition to her clinical work, Mollie is actively involved in the genetics community. She serves as a committee member for the Pennsylvania Association of Genetic Counselors and is the Vice-Chair of the Primary Care Special Interest Group for the National Society of Genetic Counselors.

“I’m deeply grateful for the opportunity to serve patients and their families at DDC Clinic, and to support the broader community of individuals affected by genetic conditions,” Mollie says.