We identified an adolescent young woman with new-onset diabetes. Due to suspicious family history, she underwent genetic testing for common monogenic diabetes (MODY) genes. We discovered that she and her father carry a novel variant of uncertain significance in the HNF1A gene. She was successfully transitioned from insulin to a sulfonylurea with excellent glycemic control. Based on her family history and successful response to sulfonylurea, we propose that this is a novel pathogenic variant in HNF1A. This case highlights the utility of genetic testing for MODY, which has the potential to help affected patients control their diabetes without insulin.
HNF1A mutations are a common cause of monogenic diabetes in patients presenting with early-onset diabetes and significant family history.
Genetic testing in suspected patients allows for the identification of mutations causing monogenic diabetes.
First-degree relatives of the affected individual should be considered for genetic testing.
The use of sulfonylurea agents in patients with HNF1A-MODY can reduce dependence on insulin therapy and provide successful glycemic control.