Hyunji Kim1,3, Hwa Young Kim2,3, Jae Hyun Kim2, Soo Hyun Seo1 and Kyung Un Park1 1Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea; 2Department of Pediatrics, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea Corresponding author: shseo81gmail.com

↵3 These authors contributed equally to this work.

Abstract

The diagnosis of maturity-onset diabetes of the young (MODY), a monogenic form of diabetes mellitus caused by a mutation in a single gene, is often uncertain until genetic testing is performed. We report a 13-yr-old Korean boy who was initially diagnosed with type 2 diabetes (T2DM). MODY was suspected because of his nonobese body habitus and family history of multiple affected members. Targeted panel sequencing of all MODY-related genes was performed using the NextSeq 550Dx platform (Illumina). Sanger sequencing was performed using blood samples from the parents, siblings, and other relatives. A frameshift variant in the 3′ region of the last exon of PDX1 was detected in the patient and his family members with diabetes. PP1_Moderate criterion was applied and this variant was confirmed to be the genetic cause of diabetes in the family and classified as likely pathogenic. The study highlights the importance of genetic testing for nonobese, early-onset diabetic patients with multiple affected family members. Increased awareness and aggressive genetic testing for MODY are needed.

Received June 24, 2023. Accepted August 22, 2023.