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Our Team

Dr. Bradley Jahnke, DO

Co-Owner, Board Certified Family Medicine

Embarking on a healthcare journey from a precarious start in my high school years, I’ve been guided by resilience and faith, leading me to the University of Florida where I pursued nutritional science, further enriching my life by meeting my wife and embracing preventive medicine.

My quest for comprehensive patient care propelled me from a clinical dietitian to embracing osteopathic principles at Midwestern University, supported by a scholarship that fostered both my education and teaching.

This path culminated in the foundation of Family Tree Primary Care in Orlando, a direct primary care practice that embodies my commitment to treating the whole person, inspired daily by my family and the journey back to my roots.

Dr. Jahnke of Family Tree Primary Care
Doctor of Family Tree Primary Care

Dr. Justin Mahon, DO

Co-Owner, Board Certified Family Medicine

Prioritizing family above his professional identity, I introduce myself as a husband and father before mentioning my role as a doctor, underscoring the importance of my wife, sons, and even my dogs to my identity.

Raised in Seminole County and educated from elementary school through medical school in Florida, my journey is deeply rooted in the Winter Park/Oviedo area, leading to a career focused on serving the medically underserved and embracing hands-on projects like woodworking.

Now, with the opportunity to contribute to the health and well-being of my hometown, I am eager to give back to the community that shaped me, blending personal passions with professional dedication.

Dr. Shanna Irizarry-Miller, DNP NP-C

Now Accepting New Patients Badge

Family Nurse Practitioner

Now Accepting Patients

We invite you all to welcome the newest member of our Family Tree Family: Dr. Irizarry-Miller, DNP! Hailing from the great state of Texas where everything is larger than life, Dr. Irizarry-Miller certainly has the resume and ambition to match! Dr. Irizarry-Miller is a U.S. Air Force Veteran, highly experienced Family Nurse Practitioner, salsa aficionado and mother to six amazing children. To say that she impresses us daily is an understatement. Don’t just take our word for how incredible she is, though! Continue reading on for her personal biography or, even better, come visit her in person here at Family Tree!

Dr. Stephens of Family Tree Primary Care

Dr. Nikole Stephens, DO

Board Certified Family Medicine

From a childhood filled with academic curiosities and a definitive dream of becoming a doctor, I navigated through extensive schooling to achieve my goal, marking a journey of persistence and dedication.

My roots are deeply planted in Florida, where my educational journey spanned from being a valedictorian and a varsity athlete in Oviedo to obtaining a medical degree and completing a family medicine residency, underscoring a commitment to excellence in both academics and athletics.

Outside the hospital, my life is enriched by hobbies that include playing board games, enjoying Orlando’s theme parks, participating in roller derby, and engaging in competitive powerlifting, reflecting a dynamic balance between personal passions and professional fulfillment.

Amazing Support & Care Staff

The Backbone of Family Tree

Adriane Jahnke

Office Administrator

Jessica of Family Tree Primary Care

Jessica Mahon

Marketing Director

Sarah of Family Tree Primary Care

Sarah Philbrook, MA

Medical Assistant

Krystal of Family Tree Primary Care

Krystal Weston, MA

Medical Office Manager

Getting to know Dr. Brad

Family in for a checkup with one of the doctors at Family Tree Primary
Dr. Mahon and Dr. Jahnke of Family Tree Primary Care smiling over a laptop

As the ancient Chinese proverb says, a journey of 1000 miles begins with the first step. My journey into healthcare began many years ago as a young man sitting in a doctor’s office wondering if I would live through my freshman year of high school. Now, many years later, I thank God for the lessons He taught me during that difficult period of my life and for the many lessons since. I don’t want to ruin the ending but I did survive my freshman year as well as the ones after and went on to the University of Florida where I received my bachelor’s in Nutritional Science and then my master’s in Nutrition and Dietetics and a minor in Exercise Science.

During my time at the University of Florida I met my beautiful wife Adriane and she joined me on this adventure. For several years I worked as a clinical dietician at SHANDs and promoted the merits of preventive medicine. Seeing first hand, the medical needs of so many patients I decided to further my education by attending medical school at Midwestern University in Phoenix, Arizona. I was impressed by the Osteopathic tenants that promote the patient being a unit made of body, mind, and spirit and stating that we should treat all facets of the individual with equal emphasis. While in medical school I applied and was accepted for a prestigious scholarship that allowed me to continue my education and teach at the University simultaneously.

During my time in Phoenix I was lucky enough to deliver both of my beautiful children Addison and Alexander who inspire me daily. The next step in my journey involved returning to my hometown in Orlando and completing the Family Medicine residency and integrated Fellowship in Neuromusculoskeletal medicine at Florida Hospital. During my final year as chief resident I learned about Direct Primary Care (DPC). Everything about DPC seemed to make sense of my entire journey. In this type of practice I could finally provide the kind of “whole-person” care I have always wanted and so was born Family Tree Primary Care.

Getting to know Dr. Justin

Doctor checking the heart of a small male child holding a Thomas the Tank engine.
2 Doctors at Family Tree Primary Care consulting on a laptop over a patient diagnosis.

When people ask me what I do for a living, I always answer, “I’m a husband and father who’s also a doctor” as opposed to “I’m a doctor with a family.” The most important parts of my life will always be my amazing wife and two beautiful sons. I guess my dogs are ok too.

I’m a local guy, been living in the Winter Park/Oviedo area since I was 2. Seminole County raised from Eastbrook Elementary, to Tuskawilla Middle and the Lake Howell class of 2000. I attended undergrad at UCF with a degree in molecular biology and microbiology, and received my medical degree at Nova Southeastern University in Fort Lauderdale, FL. I completed my Family Medicine residency at FL Hospital East Orlando. I also served as the Assistant Medical Director of the Community Care Clinic, a free clinic for the uninsured and impoverished. There I learned how to provide great care for the medically underserved on a shoestring budget.

When I grew up, I traded my Nintendo and Playstation controllers for saws and drills. I love playing around in the garage and have built nearly all the furniture in our house.

I’m beyond excited to have this opportunity to bring health and well-being to my hometown and take care of the people that have become my second family. This town raised me and now it’s time to give back!

Getting to know Dr. Shanna

Doctor listening to the heart of young male patient
Staff handing over a clipboard at Family Tree Primary Care

I wasn’t really sure what I wanted to be when I grew up. I knew I liked science, and I loved music and theater…but I wasn’t confident in the career I’d have as a musician or an actor. I let my pragmatism choose for me and headed off to Texas Woman’s University to major in Nursing. I figured I’d always have a job in health care. Lucky for me, it turned out I loved Nursing.

After graduating, I worked at the University of Texas Southwestern Medical Center, on a busy inpatient Medical-Surgical floor. The experience at UT Southwestern was invaluable, however I felt I was meant for more, so I joined the Air Force. 

While in the Air Force, I applied for the Air Force Institute of Technology scholarship for the Family Nurse Practitioner program at the Uniformed Services University of the Health Sciences. I chose family care, because I love caring for patients of all ages, and couldn’t possibly limit myself to one specialty. I graduated with a Doctorate of Nursing Practice, and headed for San Antonio to work in the Family Health Clinic at Randolph Air Force Base. I could go on and on about what I have gained from my military experience, but there’s not enough space on this page, so you’ll just have to ask me.

Unlike my esteemed colleagues, I’m not from around here. I was born and raised in the Texas Hill Country, though you’d never guess from talking to me. I have more subtle indicators, like how I immediately judge a Mexican Restaurant based off its salsa, or my obsession with H-E-B (if you know, you know). I’ve ended up here for a very important reason, my family. While stationed in San Antonio, I met the love of my life while he was in town for some training. Turns out, he was from Oviedo. Between the two of us, we now have seven kids, and the only way for us to be together all the time, was for me to separate from the Air Force, and move here! 

Sometime between our 5th and 6th kid coming into this world, if not at the clinic, you’d find me on a sand volleyball court, lifting in our home gym, in my backyard building a patio or gardening, fiddling around with my ukulele, or trying to improve my amateur photography skills. Life’s a little more complicated now, and I have less free time…but I welcome the trade, and am sure I’ll revisit all of my former free-time passions soon.

Getting to know Dr. Nikole

Doctor meeting with an older male patient discussing his health care
Doctor checking a female patient's shoulder after an injury

As a kid, when asked ‘what do you want to be when you grow up?’, rather than a “movie star”, or  “ police k-9 officer” I opted for a “doctor.”  After a childhood of math games, home chemistry sets, and lots of schooling, I can thankfully say I saw that goal through. It’s been a long and difficult road, but I’m here now.

I’m a Floridian, born and raised. I’ve resided in both the Orlando and Oviedo areas. I attended Faith Chrisian Academy for both Middle and High School, where I graduated as Valedictorian and a three sport varsity athlete. I received a Bachelor of Science in Biology at the University of Florida and a Master of Science in Medical Science from the University of South Florida. I earned my medical degree from the Lake Erie College of Osteopathic Medicine Bradenton and further honed my skills at the Family Medicine Residency at AdventHealth East Orlando. 

In my free time, I enjoy playing board games with my husband, and going to Orlando’s wonderful theme parks with my family. I’ve been a long time Roller Derby player, which I started in the Bradenton area with the Bradentucky Bombers and am currently skating for Orlando Roller Derby. I’ve been a lifelong athlete, and have recently started competitive powerlifting. Additionally I attended Crossfit classes regularly and I also exercise in the ‘dirt gym’ my husband ‘curated’ behind our house.