Maturity-onset diabetes of the young (MODY) is an autosomal dominant form of diabetes that presents before the age of 25. It is caused by mutations in genes that play a role in beta-cell function. Some of these genes include HNF1A, HNF4A, and GCK.
Most cases of MODY are misdiagnosed as either type 1 diabetes or type 2 diabetes.
Classification of MODY
| Classification | Description |
|---|---|
| Glucokinae MODY | Caused by mutations in the glucokinase (GCK) gene. |
| Transcription factor MODY | Caused by mutations in genes encoding B-cell transcription factors (HNF1A, HNF4A, and HNF1B gene). |
| Syndromic MODY | Associated with diabetes and extra-pancreatic features such as renal cysts and genital tract abnormalities. |
Some common subtypes of MODY
| Subtype | Description |
|---|---|
| MODY 1 (HNF4A) | Progressive beta-cell dysfunction that leads to increasing hyperglycaemia. Associated with macrosoma and neonatal hypoglycaemia. Responds to low-dose sulfonylureas. |
| MODY 2 (GCK) | Caused by mutations in the glucokinase gene, which affects glucose sensing. Presents with mild, stable fasting hyperglycemia (5.5- 8.0 mmol/L). Rarely requires treatment except during pregnancy. |
| MODY 3 (HNF1A) | The most common subtype. Characterised by glycosuria at relatively normal blood glucose levels. Highly sensitive to sulfonylureas. |
- Patient history
- Diabetes onset before 25 years of age
- A strong family history of diabetes spanning three generations
- Lacks the typical features of type 2 diabetes, such as obesity and metabolic syndrome
- Normal or elevated C-peptide levels indicate preserved beta-cell function
- Absence of type 1 diabetes-related autoantibodies
- Investigations