Classifying diabetes into two types (1 and 2; T1D, T2D) is an oversimplification. Many causes can result in poor insulin secretion. Maturity-onset diabetes of the Young (MODY) can be due to rare variants in >35 genes. The diagnosis often leads to therapy changes. We investigate patient groups (the FINNMODY, DIREVA or FinnDiane cohorts, the Pediatric Diabetes register) with insulin deficiency aiming to 1) identify all patients with MODY in Finland & genetic mutations causing it, clinical characteristics and risk of diabetes; 2) study the role of MODY genes in patients diagnosed with type T1D or T2D; 3) identify new genes/variants causing monogenic diabetes; 4) study the metabolic consequences of rare variants associated with T2D by comparing subjects with and without them using advanced metabolic phenotyping. Unravelling the heterogeneity of diabetes and identification of more homogenous subgroups will inform understanding of the disease mechanisms and personalizing treatment.

2024

2028