Monogenic diabetes: recent updates on diagnosis and precision treatment: A narrative review

Monogenic diabetes is commonly caused by single-gene mutations. This disease ranges from 1% to 5% in all cases of diabetes and is less affected by behavior and environment. Neonatal diabetes mellitus (NDM) and maturity-onset diabetes of the young (MODY) account for a major proportion of monogenic diabetes, while syndromic diabetes constitutes a smaller proportion. Diagnosis of monogenic diabetes has improved from being based on clinical phenotypes to molecular genetics, with significant advancement of genome sequencing skills. Precise medication for monogenic diabetes is based on genetic testing; therefore, an accurate diagnosis is essential. Due to the basic clinical criteria (diagnosed < 6 months of age), genetic testing and precision treatment for NDM are fast and uncomplicated. The MODY probability calculator was developed; however, it remains challenging to distinguish MODY from type 1 and 2 diabetes due to the lack of a single diagnostic criteria and genetic testing. Additionally, the high cost and complicated interpretation of these genetic test results add to these challenges. This review will discuss the distinct etiology and subgroups that contribute to predicting and treating clinical phenotypes associated with monogenic diabetes. Furthermore, we will review the recent Korean studies and suggest methods of prioritizing patient screening for genetic testing.