Using genetic testing, doctors help patient find answers for her diabetes

This story was originally published on November 21, 2025.

Autumn Caris, now 44, was diagnosed with type 1 diabetes as a teenager.

Her initial symptoms included thirst, frequent urination and migraine headaches.

When her mother took Caris to the emergency room, the medical team found that her blood sugar was five times the normal amount and immediately taught her how to inject insulin.

Her condition, however, didn't stabilize.

“My insulin levels kept fluctuating throughout my teenage years,” Caris said. “The doctor assured me that I was ‘honeymooning’ and that eventually it would be OK.”

The honeymoon phase of type 1 diabetes refers to a temporary period when the body takes time to adjust to its insulin needs.

The length of the phase differs because the insulin-producing cells eventually die in patients with type 1 diabetes, changing the amount of insulin that needs to be given.

Once she started her undergraduate studies, Caris was put on a different insulin regimen that consisted of a pre-mixed combination of intermediate- and short-acting insulin.

This approach also failed to control her blood sugar levels.

Years later, when Caris and her husband decided to have children, she was put on an insulin pump to ensure a safe pregnancy.

Even though she had a healthy pregnancy, Caris gained more weight than expected and required 300 units of insulin every day, which was higher than what the pump was able to hold.

While most patients change their insulin pumps every two to three days, Caris had to change her pump daily to keep up with her insulin needs.

For 17 years, she remained on her pump and despite her efforts, her blood sugar level did not normalize and she was unable to lose weight.

Eventually, she voiced her concerns to her endocrinologist.

“I knew that something was not right based on how much insulin I was taking,” Caris said. “Even though I didn’t eat a lot of carbs and tried to stay active, I wasn’t losing weight.”

Her endocrinologist believed that Caris might be resistant to insulin, which would explain her weight gain.

Not satisfied with this answer, Caris decided to work with her primary care doctor to try new medications that could help her. After several discussions, her doctor prescribed an oral medication called metformin in addition to her insulin pump.

However, the medication caused severe gastrointestinal upset, forcing Caris to stop taking it.

Finding new solutions with the help of a podcast

In 2022, Caris started listening to the Juicebox Podcast that offers listeners insights into diabetes care and management.

She discovered that for some patients with type 1 diabetes, Ozempic, which is recommended for type 2 diabetes, was helpful in treating insulin resistance.

After consulting and obtaining a prescription from her primary care physician, Caris noticed that her insulin needs were reducing over time as she increased the amount of Ozempic.

“Although I didn’t lose weight, I felt healthy, inflammation was gone and I wasn't tired all the time,” Caris said.

Due to issues with what her insurance would cover, Caris had to change the type of weight loss medication a few times.

Regardless of the drug, her insulin levels remained stable.

Caris found more answers for her condition when, in another episode of the podcast, she learned that patients with type 1 diabetes have multiple types of autoantibodies that attack insulin-producing cells, leading to the disease.

She wondered whether she had these antibodies and asked her primary care provider to test her for them.

“They found that I had none of the antibodies found in type 1 diabetes,” Caris said. “I knew that I needed to find an endocrinologist who would help me understand what was happening.”

Her search brought her to Rachel Reinert, M.D., Ph.D., an assistant professor of internal medicine at the University of Michigan Health and a member of the Caswell Diabetes Institute.

Diagnosing a rare type of diabetes through genetic testing

Using additional tests, Reinert was unable to confirm that Caris had type 1 diabetes. Her pancreas was still making insulin, which is uncommon in patients with long-term type 1 diabetes.

In March 2025, Reinert recommended that Caris go through a trial period off the insulin pump. Instead, she would try non-insulin therapies that would help manage the excess weight that was contributing to insulin resistance.

Since removing her pump, Caris has lost 50 pounds and has lower insulin needs.

“I couldn’t believe that I had been misdiagnosed for over 30 years,” Caris said. “I wanted to find out why none of my previous doctors had realized that something was wrong.”

Her search for answers led her to learn about maturity-onset diabetes of the young, or MODY, which is misdiagnosed as type 1 or type 2 diabetes in 50-90% of the cases.

This rare type of diabetes was first described by Stefan Fajans, M.D., then a professor of internal medicine in the division of metabolism, endocrinology and diabetes. 

It usually presents in early life and is caused by a mutation in a single gene, whereas type 1 and type 2 diabetes involve a combination of multiple genetic and environmental risk factors.

“When Autumn came to me with her suspicions, I put her in touch with our genetics team. They identified a specific mutation in a gene called PDX1, which causes a rare type of MODY,” Reinert said.

During embryo development, PDX1 is responsible for specifying which cells turn into the pancreas and insulin-producing beta cells.

The gene mutation prevents the pancreas from developing properly and patients with this MODY type have impaired beta cell function.

Reinert collaborated with David T. Broome, M.D., M.S., Clinical Assistant Professor of Internal Medicine and Principal Investigator of University of Michigan’s long-term study of MODY-monogenic diabetes study and Co-Chair of the PREcision Diabetes ConsorTium. 

Broome had previously published that treatment approaches for MODY need to be tailored to the specific type of MODY variant a patient has.

After discussing her options with her care team, Caris transitioned off daily insulin injections and is now taking low doses of glipizide and once-a-week tirzepatide. Both drugs work by stimulating insulin release from the pancreas. 

“Within the first week, my blood sugar levels went from 135 to 110 mg/dL and I have never felt better,” Caris said.

“I can finally have a life filled with fun and excitement, instead of being bogged down by a chronic illness, which can feel like a death sentence.”

Today, Caris is thriving without insulin. In addition to spending time with her family, Caris spends her time talking about her experience and helping other patients understand the importance of advocating for themselves and ensuring that they feel comfortable discussing questions with their care team.

Diagnosis helps Caris and her father find answers for his diabetes

Paul Caris was diagnosed with diabetes in his early 30s, and his doctors mistook him to have type 1 diabetes. 

Even though he tried to manage his condition, his blood sugar remained high for years and he developed coronary artery disease, chronic kidney disease and obesity.

After his daughter received her genetic diagnosis with Reinert and Broome, she insisted that he meet with Broome since he had the same genetic mutation.

Working with Broome, he was transitioned off multiple daily doses of injections and is taking glipizide and tirzepatide, which has helped him the amount of insulin he needs. 

Further, he has seen an improvement in his kidney disease and a lower body weight.

Both Autumn and Paul Caris were recently reported as the first participants with PDX1-MODY who have had a profound response to treatment with tirzepatide, and their cases were presented at the 2026 annual meeting of the Endocrine Society.

“I'm excited for the fact that Autumn and I are doing so well,” Caris said.

“Even though I still take insulin, it's reducing each month I am hoping that, like Autumn, I will be off insulin eventually.”

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