Background.
The WHO 2019 classification of diabetes mellitus introduced two new subgroups: Hybrid forms and the unclassified. This means that some cases of diabetes mellitus (DM) do not fit into established forms of DM such as Type 1 and Type 2.
Report. This case describes a new form of DM that is different from the two forms of Hybrid forms of
diabetes described by WHO in 2019. The patient presented with severe hyperglycaemia, low C-
peptide value, no ketonuria and needed large doses of insulin to achieve normoglycaemia.
Subsequently, C-peptide became normal and metformin with diet and lifestyle measures controlled the blood glucose. To our knowledge this type of DM has not been classified. We describe this as a third type of Hybrid diabetes.
Conclusion. This adolescent presented with some features of Type 1 diabetes mellitus, but within three years regained normal beta cell function and continuous monitoring shows normal blood glucose values with diet and oral hypoglycaemic
drug, Metformin. We describe this as the third type of Hybrid class of diabetes mellitus.