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Our Team.

Dr. Ronald Sanzone
Ronald Sanzone, D.O. is board certified in Family Medicine. He received his medical education at the College of Osteopathic Medicine and Surgery and completed his residency at Oakland Community Hospital. He is the founder of Gateway Medical Group. He was the chief of Family Medicine at Sharp Chula Vista for 8 years and on the Board of Governors at Sharp Chula Vista for 3 years. He was the Chief of Family Medicine at Paradise Valley Hospital for 6 years. His hobbies include wood working at Palomar College, chess (rated 1650 in the U.S. Chess Federation) and fishing.
Dr. Merritt Matthews
Merritt Matthews, M.D. is board certified in Family Medicine
Dr. Rafael Garcia
Rafael Garcia, M.D. is board certified in Pediatric Medicine. 
Dr. Gustavo Mondragon
Gustavo Mondragon, Jr., M.D. is board certified in Family Medicine.
Dr. Joseph Novencido
Joseph Novencido, D.O. is a board certified Family Physician. Born and raised in San Diego, CA, he received his undergraduate education at UCSD before traveling to Chicago to embark on his career in medicine. He received his medical education at Midwestern University CCOM in Chicago then completed his residency training within the UC Davis Family Medicine Residency Network at the Valley Consortium of Medical Education in Modesto, CA in 2015. He returned to San Diego to join Gateway Medical Group, determined to serve his home town community with medical care that is both evidenced-based and personalized. He has a special interest in preventative medicine, and he strives to help his patients achieve and maintain happy, healthy, and functional lifestyles. 
Outside of medicine, he loves spending time with his wife and son. He enjoys traveling, reading, writing, running, and photography. He has a strong appreciation for different cultures, nature, art, and architecture. 
Marites Macasadia, PA-C
Hello. I am Marites Macasadia. I am a Physician Assistant and I have been working for Gateway Medical Group for over 20 years. I did my undergrad at UCSD and graduated in 1995. I completed the PA program at USC in 1999. I've called San Diego home for most of my life. I'm married and I have a daughter. I love to travel and spend time with my family and friends. My passion is caring for others, so that is why I got into the medical field. Here are the words that I live by:
Sandra De Roldan, NP
Sandra De Roldan received her Nurse Practitioner master degree at the United States University in San Diego in 2012. She completed her registered nurse training at Grossmont College in 2006. She graduated from medical school at La Universidad Michoacan De San Nicolas De Hidalgo, in Morelia, Mexico. She joined Gateway Medical Group in 2011.
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