1 Introduction Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes characterized by autosomal dominant inheritance. To date, 14 distinct MODY subtypes have been identified, among which HNF1A-MODY, caused by HNF1A gene mutations, represents one of the most prevalent subtypes, accounting for 30-70% of all MODY cases (1). However, recent study indicates that within the Chinese MODY population, the proportion of HNF1A-MODY cases is 16.03% (2).