Meet Us

Dr. Greg Garrison

Dr. Garrison has been practicing pediatrics since 1996.  After receiving his Bachelor of Arts in Communication from Judson College he pursued other undergraduate work in Chemistry and Biology at St. Louis University and Southern Illinois University – Edwardsville. He received his Medical Degree from Southern Illinois University in 1993 and completed his pediatric residency at Arkansas Children’s Hospital in Little Rock, Arkansas in 1996. He spent 3 years working as a general pediatrician at the Sherwood Family Medial Clinic in Sherwood, Arkansas. In 1999, he moved to southern Illinois and founded St. Clair Pediatrics. Dr. Garrison is a member of the St. Clair Medical Society, the Illinois State Medical Society, the American Medical Association, and the American Academy of Pediatrics. He lives in O’Fallon with his wife and is the proud father of two daughters.

Brittanie BardonCPNP 

Brittanie grew up in Kansas City, MO and attended college at the University of Missouri – Columbia. She received her Bachelor of Science in Biology in 2010, going on to obtain her Bachelor of Science in Nursing through the Accelerated Program at Sinclair School of Nursing in 2011. She always had a passion for pediatrics and was thrilled to become a pediatric registered nurse just after graduation at SSM Health Cardinal Glennon Children’s Hospital on the infant/toddler medical-surgical floor. She then received her Masters of Science in Nursing with focus on Pediatric Primary Care from Saint Louis University in 2016. She is board-certified by the Pediatric Nursing Certification Board and a member of the National Association of Nurse Practitioners. She resides in the St. Louis area with her husband, Jeff, and adorable cat, Bruce Wayne, and in her free time enjoys cheering on the Blues and Cardinals!

Katherine ConklingCPNP

Katie grew up in Glen Carbon, IL and obtained her Bachelors of Science in Nursing from Goldfarb School of Nursing at Barnes-Jewish College in 2013.  She worked for 1 year on an adult orthopedic floor, and then pursued her passion for pediatrics at Cardinal Glennon Children’s Hospital.  She worked there for more than 4 years on the Infant/Toddler Medical/Surgical unit, and became a Certified Pediatric Nurse.  She completed her Masters of Science in Nursing, focusing on Pediatric Primary Care, from Maryville University in 2017.  She is a board-certified Pediatric Nurse Practitioner by the Pediatric Nursing Certification Board (PNCB), a member of the National Association of Pediatric Nurse Practitioners, and a member of Sigma Theta Tau International Honor Society of Nursing.  She is enjoying newlywed life with her sweet husband, Ben, and still resides in IL.  In her spare time enjoys hanging out with her family, listening to music, being outside, and swimming in her pool!  

Melissa TholeFNP-C

Melissa grew up in Highland, Illinois and obtained her Bachelor of Science in Nursing from Chamberlain College of Nursing in 2009. She worked for one year on a Medical Oncology floor and then spent eight years as a Labor and Delivery/Mother-Infant/Level 2 Nursery nurse. She then came to St. Clair Pediatrics where she worked for one and half years as a Pediatric Nurse. She completed her Master of Science in Nursing, focusing on Family Primary Care, from Chamberlain College of Nursing in 2018. Melissa is now a board-certified Family Nurse Practitioner by the American Nurses Credentialing Centers and was a member of Sigma Theta Tau International Honor Society of Nursing. She resides in Highland, Illinois with her husband Scott and three beautiful daughters Adalyn Avery and Audrey. In her free time she enjoys spending time with her girls and her dog, camping, and spending time outside on her deck.

Front Desk Team

Lupi Castillo

Practice Manager

Shana Hanley


Candace Jones


Tiffany Voelker


Susan Deboise


Nursing Team

Paula Dori


Savanna Steed


Paige Etling


Ashley Clinton


Morgan Schniers


Savannah Loeffen

Medical Assistant

What Our Families Are Saying

Hollie H.

Dr. Garrison and his staff are just the best!!!! I could not ask for a better pediatrician for my son!! I would highly recommend them to anyone! 

Catrina H.

We just switched to them and I’m so glad we did! The office is beautiful and clean and everyone there is very friendly and helpful.

Karen R.

As stressful as it can be to bring your sick child into the pediatrician’s office, the staff at St. Clair Pediatric’s always know how to provide a calm & comforting environment! The care provided by their staff is nothing short of spectacular.