Residents

Anna Buck, DO

Hello there! My name is Anna Buck. I was born and raised in Minnesota and attended the University of Minnesota for my undergraduate education. I moved to Colorado in 2019 to attend medical school at Rocky Vista University and loved it so much, I stayed for residency! I love working with a diverse
population of patients and have special interests in global health, reproductive care, and lifestyle medicine. In my free time, you can find me on the running trails, attending yoga classes, snuggled up
with a good book and my rescue puppy, or baking one of my favorite recipes. I can’t wait to continue my learning as a part of the HealthOne Family Medicine Residency Program!

Mattie Brand, DO

Dr. Brand is a dedicated family medicine resident who is passionate about integrating lifestyle medicine into patient care, with a focus on women’s health and mental well-being. Outside of the clinic, you'll often find Dr. Brand exploring nature through hiking trails or road biking. As a culinary enthusiast, she enjoys experimenting with new recipes and ingredients in the kitchen. Balancing her professional and personal life, Dr. Brand cherishes time spent keeping up with her energetic toddler, fostering a well-rounded approach to health both at work and at home.

Cornerstone Family Practice is honored to be the training site for the HCA/HealthOne Family Medicine Residency Program in Aurora. We have 25

residents from all over the country who spend 3 years with us completing the final step in their training. The majority of our graduates go on to be outpatient clinicians here in Colorado or they return to their hometown. They all bring their own special interests and personalities to the clinic and allow us to offer something very unique to our community. If you would like to learn more about the residency programs and opportunity for training please visit the HCA/HealthOne Residency website. You can also visit them on Facebook, Instagram and YouTube

Lauren Gilbert, M.D.

Hi! My name is Lauren Gilbert, and I’m from Brighton, Michigan. I went to college at the University of Michigan (Go Blue!) and medical school at Central Michigan University. I am thrilled to be here in Aurora as I am passionate about caring for patients of various ethnicities, backgrounds, and cultures in an urban-underserved area. My professional interests include pediatrics, women’s health, obstetrics, sports medicine, and global health. Outside of medicine, I enjoy traveling, cooking, snowboarding, playing volleyball, and cuddling with my orange cat, Moose!

Katie Jackson, D.O.

"Hi everyone! I'm Katie. I'm originally from Los Angeles, CA, but I've also lived in New York, NY and London, England. I graduated from Richmond, the American University in London, where I studied communications and art, design, and media. After working in a small media production company, I changed careers and worked as a birth support professional, also known as a doula. This experience gave me a passion for working with clients through pregnancy and birth. I went on to complete medical school at Western University of Health Sciences, College of Osteopathic Medicine of the Pacific. I also spent an extra year learning hands-on Osteopathic Manipulation Medicine. In my free time, I enjoy spending time with my husband, two children, and our dog, camping, and trying new foods. I believe that everyone deserves access to quality healthcare, and I am committed to helping everyone live healthier, happier lives. I am excited to be part of the team at Cornerstone Family Practice."

Claire Levinson, D.O

I was born and raised in Denver, CO. I received my Bachelor of Science in Environmental Engineering from CO School of Mines. After working as a civil engineer for 2 years, I made a career shift towards healthcare and graduated from Rocky Vista University College of Osteopathic Medicine. My interests include lifestyle medicine, adolescent medicine, obesity medicine, and LGBTQ health. I am passionate about providing inclusive and equitable patient-centered care in Denver, CO; the city I was raised in and have called home for the past 30 years. Outside of medicine, I value my family, fitness, and spending time with my two spunky Goldendoodles.

Kelly Mohr, D.O.

Hello! My name is Kelly Mohr and I was lucky enough to grow up right here in beautiful Colorado. I completed my undergrad at CU Boulder (sko Buffs!) and medical school at Rocky Vista University in Parker, Colorado. When I'm not in the clinic, I enjoy all the classic Colorado outdoor activities like hiking, biking, skiing, and camping. I also enjoy a good book, traveling, and eating all the yummy foods from all over the world. I am passionate about preventative medicine and providing broad spectrum care to anyone and everyone. I am excited to train with HealthONE Family Medicine Residency and am looking forward to serving my community!

Mikayla Mollnow, D.O

My name is Mikayla, I grew up in Colorado, attending both college and medical school here. My medical interests include preventative medicine and advocacy as well as nutrition, dermatology, and minor skin procedures. I strive to foster a relationship in which I can provide my patients with information and education to empower them to be active participants in their own health journey. Outside of medicine I enjoy all the great outdoor activities of the state including walking, hiking, climbing, and camping, and indoor activities as well, including reading and playing piano. I intend to continue practicing medicine and serving my Colorado community as best as I can.

Alexa Trenschel, D.O.

Hi! My name is Alexa and I moved around quite a bit as a kid and was lucky enough to experience a quite few different places on my way to beautiful Colorado! I went to undergrad at both UT Austin and ASU and received both my Masters and Doctorate degrees at Midwestern University in Glendale, Arizona. My professional passions lie in addiction medicine, lifestyle medicine, sports medicine, and providing accessible and equitable healthcare. Outside of clinic I enjoy snowboarding, skating, mountain biking, rock climbing, and all things outside.

Diana Garcia, DO

Hola! My name is Diana Garcia. I’m originally from Lamont, California, and moved to Texas in 2012. I completed my undergraduate studies through a fast-track program at Midland College, which allowed me to pursue my medical education at the Texas College of Osteopathic Medicine.

My passion lies in Family Medicine because of the meaningful continuity of care and the lasting relationships formed with patients. I strongly believe in empowering individuals to take charge of their health and am deeply committed to patient education and advocacy. I’m especially passionate about serving underserved communities and making quality care accessible to all.

Outside of medicine, I enjoy spending time with my husband, family, and friends, going on travel adventures, and relaxing with my cat, Leo. I’m honored to continue my training and to be part of the dedicated team at Cornerstone Family Practice.

Mason Mangapora, DO

Hi, my name is Mason Mangapora. I was born and raised in Ohio where I attended the Ohio State University and got my Pharmaceutical Sciences degree. I then travelled further south in Ohio to study medicine at Ohio University in Athens. I'm passionate about lifestyle, wilderness, and sports medicine. In my free time, you can find me out on a hiking trail exploring beautiful Colorado! I can't wait to serve this community and look forward to meeting all of you.

Morgan Reich, DO

"Originally from rural Minnesota, I am a family medicine resident with a deep commitment to serving the people of Colorado. I completed my undergraduate studies at Bethel University in St. Paul, MN, where I met my husband. Together, we moved to Colorado for medical school, and I earned my degree from Rocky Vista University College of Osteopathic Medicine. We quickly fell in love with the state’s vibrant communities and stunning landscapes—and chose to stay for residency.

My clinical interests include pediatrics, women’s health, and lifestyle medicine. I believe in a holistic approach to care and am passionate about building lasting relationships with patients and families. Outside of medicine, I enjoy spending time with my two wonderful children and our two energetic golden retrievers. You can often find us hiking Colorado’s scenic trails, reading together, or enjoying the simple joy of being outdoors as a family."

Erin Onat, DO

Hi! I’m Dr. Erin Onat, and I was born here in Colorado where I have spent my whole life. I graduated from the Colorado School of Mines with a degree in chemical engineering and went on to work as an engineer for a few years. Engineering was fascinating, but I ultimately decided to pursue medicine…a choice I am so happy to have made! I chose Family Medicine because I especially enjoy working with patients on a long-term basis. I am excited to join forces with my patients here at Cornerstone Family Practice to promote happy, healthy lives. In my free time, I am a huge dog lover and can be found in the gym, going on long walks with my dog, and spending time with my family.

James Willis, DO

Hi! My name is James Willis. I am originally from Aurora, Colorado and am very excited about the opportunity to be back in the community I grew up around. I did my undergraduate education at Western Colorado University earning a Bachelor's of science in Biology. I then continued at Western to complete a Master's of Science in High-Altitude Exercise Physiology. Lastly, I ventured out to Monroe, Louisiana for my medical education at Edward via College of Osteopathic Medicine. I am most passionate professionally about lifestyle medicine and sports medicine. During my free time I enjoy spending time with my wife, two little kids and two dogs. My family and I are very happy to be back in Colorado!

Analekha Chesnick, DO

My name is Lekha Chesnick. I am originally from Tucson, Arizona and attended the University of Arizona for my undergraduate education. I made my first move to New Mexico in 2020 for medical school where I completed a rural distinction track at the Burrell College of Osteopathic Medicine, I met my husband in medical school and together we couples matched for residency here in Colorado! In my free time I love long-distance running and you can usually find me on the Cherry Creek Trail with my Australian shepherd, Kona. I also love cooking, yoga, sound healing, reading, knitting and watching reality TV with my two cats, Raja and Jedi. Clinically, I am passionate about health equity, lifestyle medicine and osteopathic treatments. I am honored to be a part of the HealthONE Family Medicine Residency team and am committed to providing patient-centered care!

Baley Helton, DO

Hi, my name is Baley Helton. I was born and raised in a small town in Texas. I attended Texas State University where I got my Bachelor of Science. I then attended medical school at Texas College of Osteopathic Medicine. Beautiful Colorado convinced my wife and I to leave Texas for the first time for residency. I love playing basketball, finding
good coffee, and hiking trails! I am passionate about obstetrics and sports medicine and I hope to practice in a small town to give back to a community like the one I grew up in.

Christine Nguyen, DO

I’ve always been drawn to family medicine because of the wide range of care it allows me to provide. I love that I can build lasting relationships with patients and be there for them through all stages of life. The continuity of care is something that truly resonates with me, and I’m passionate about using evidence-based medicine to come up with care plans with my patients, so we can work together toward healthier lives.

I come from a family of immigrants, and growing up, I often found myself advocating for my parents, especially in healthcare settings. That experience helped shape the kind of doctor I strive to be today: someone who listens, advocates fiercely, and always puts patients first.

My husband is also a family medicine physician and we’re excited about the possibility of working together in the future! We have two little kids who keep life busy and fun. Outside of medicine, I love spending time with my family and friends, and I enjoy playing tennis, working out, and getting competitive with a game of pickleball.

Cassidy Coker, DO

Tyler Kellis, MD

My name is Tyler Kellis, I was raised in a suburb of Phoenix, AZ called Surprise and completed my undergraduate education at Brigham Young University in Laie, Hawaii and Provo, UT. I attended University of Utah School of Medicine where I developed a love for the field of family medicine and the variety of interests it offers to curious minds. I have interests in sports medicine, wilderness medicine, and lifestyle medicine. With me in Colorado is my family, including my wife and two sons. We love trying new restaurants, hiking, camping, and making new friends. To relax, I play sports, paint, and go fly fishing. I am thrilled to be in Colorado at a family medicine residency that prioritizes resident wellness and prepares residents to serve communities local and abroad!

Dasha Fedorova, DO

Hello! My name is Darya Fedorova - though I go by Dasha! I was born in Ukraine and moved to the U.S. when I was 11 years old. I completed my undergraduate studies in San Francisco and later moved to Colorado for medical school at Rocky Vista University. I speak both Ukrainian and Russian, and I’m passionate about global health and making preventive care more accessible to all. When I’m not in the clinic, you can find me in nature, camping, with my husband or relaxing at home with our three cats - Donnie, Billy, and Ernie!

Michaela Littlefield, DO

Hi, I’m Michaela Littlefield! I’m a Colorado native, proud CU Buff alumna, and graduate of Rocky Vista University College of Osteopathic Medicine. Family is everything to me, and I’m grateful to have matched in Colorado alongside my husband, who is currently an orthopedic surgery resident at CU.

I chose family medicine because I love the variety it offers, from newborn care to geriatric medicine, and the opportunity to build lasting relationships with patients across all stages of life. My clinical interests include pediatrics, women’s health, and lifestyle medicine, and I strive to take a whole-person, compassionate approach to care.

My grandfather has practiced osteopathic family medicine for 50 years, and he remains one of my greatest inspirations in medicine. It’s my dream to one day carry on his legacy and continue serving the Colorado community he’s built relationships with for decades.

Outside of medicine, I enjoy traveling, reading, and spending time with my husband, friends, and family. I also have a passion for dance and spent three seasons as a cheerleader for the Denver Broncos; this experience that taught me the value of teamwork, discipline, and community outreach!

I’m honored to be a part of the Cornerstone Family Practice team and look forward to serving and learning from our patients every day.

Nastassja Michel, DO

Sabra Rahme, DO

Welcome to Cornerstone! My name is Nastassja and I am a first generation American and Colorado native. I completed my undergraduate degree in Biology at Metropolitan State University and attended medical school at Rocky Vista University in Parker, Colorado. I am grateful to have stayed in Colorado throughout my education, as my primary goal is to provide exceptional care to members of my community. In my free time, I love to spend time in my garden, work on house projects with my husband, and hangout with my Siberian cat, Basil!

Hello! My name is Sabra Rahme. I attended medical school at Lincoln MemorialUniversity and recently moved to the Denver area from Memphis, TN where I attended University of Memphis for undergrad— Go Tigers! As a Family Medicine resident, I am excited to provide personalized, continuous, and coordinated care for the whole family. From preconception planning and obstetrics to newborn care and geriatrics, I value partnering with my patients to deliver holistic care
rooted in trust and kindness. I have a special interest in obstetrics and urogenital health, including recurrent urinary tract infections, incontinence and sexual dysfunction. I’m also committed to offering
affirming, inclusive primary care for LGBTQ+ individuals and families across all stages of life.

Outside of work, I love spending time with my husband and doting over our two sweet rescue dogs. I enjoy all things outdoors, art and will never say no to a good thrift store adventure. I also love exploring Denver’s vibrant local food scene.

Whitney Szeliga DO

Lauren Walters MD

Hello my name is Whitney Szeliga and I am a Colorado native from Littleton. I did my undergraduate education at both the University of Iowa and the University of Colorado, graduating with degrees in Spanish language and literature and integrative physiology. I got my master’s from Regis University focusing on biomedical science and genetics and genomics. I did my medical training at Rocky Vista University in Parker, CO. I have a passion for global medicine, sports medicine, osteopathic medical manipulation, and obstetrics care. In my free time you can find me practicing Muay Thai (MMA), running, biking, baking sourdough or watching Star Wars. I am honored to being doing my residency in my home state, serving the community that I grew up in. I want my practice to focus on long-term patient relationships, sideline medicine, and traveling to as many countries as I can providing quality, culturally aware medical care.

Hi, my name is Lauren Walters, and I grew up in Windsor, Colorado. I attended University of Colorado in Boulder for undergrad and Creighton University in Omaha, Nebraska for medical school. My special interests include women’s health, pediatrics, mental health, and lifestyle medicine. However, I am excited to provide equitable and compassionate care to a diverse patient population and am committed to educating my patients about their bodies and health. Outside of medicine I enjoy hiking, lifting weights, practicing yoga, reading a good book, and spending time with my partner and our cat, Margot. I am excited to be a part of the HealthONE team here in Auora and become a well-rounded family physician!