BACKGROUND: Werner syndrome (WS), also called adult progeria, is a rare hereditary progeroid disorder characterized by highly heterogeneous clinical manifestations, often leading to delayed diagnosis or misdiagnosis. Diabetes mellitus affects ~ 55% of patients with WS but is frequently misclassified as type 1 or type 2 diabetes due to overlapping metabolic features. This report aims to highlight the diagnostic challenges of WS-associated diabetes, emphasize the role of genetic testing in establishing the correct etiological diagnosis, and demonstrate how precision treatment concerning the underlying genetic defect can improve glycemic control and patient outcomes.

CASE REPORT: A 50-year-old man was admitted to the First Affiliated Hospital of Xinjiang Medical University in September 2024 with a history of poorly controlled diabetes. He exhibited diabetes mellitus, hyperlipidemia, hoarseness, and atrophy of subcutaneous fat and muscles in the face and limbs. His parents were consanguineous. Genetic sequencing revealed a homozygous mutation in the WRN gene (c.1846G>C, p.Ala616Pro), confirming the diagnosis of WS. His diabetes was subsequently reclassified as a specific type of monogenic diabetes rather than type 2 diabetes, and an appropriate precision treatment plan was developed.

CONCLUSIONS: This case underscores the importance of recognizing the association between WS and diabetes mellitus, particularly in patients with signs of premature aging. Early diagnosis and individualized management strategies are crucial for improving patient outcomes. Genetic testing plays a key role in confirming the diagnosis of WS and preventing misdiagnosis as type 1 or type 2 diabetes. This case also highlights the importance of identifying and managing rare diseases in clinical practice.

Keywords: Werner Syndrome, Progeria, Adult, genetic testing, Case Reports