| Type | Genetic defect | Frequency | Beta cell defect | Clinical features | Risk of microvascular disease | Optimal treatment |
| 1 | Hepatocyte nuclear factor-4-alpha | <10% | Reduced insulin secretory response to glucose | Normal renal threshold for glucose | Yes | Sulfonylureas |
| 2 | Glucokinase | 15 to 31% | Defective glucokinase molecule (glucose sensor), increased plasma levels of glucose are necessary to elicit normal levels of insulin secretion | Mild, stable, fasting hyperglycemia, often diagnosed during routine screening. Not progressive. | Generally no | Diet |
| 3 | Hepatocyte nuclear factor-1-alpha | 52 to 65% | Abnormal insulin secretion, low renal threshold for glucose | Low renal threshold for glucose, +glycosuria | Yes | Sulfonylureas |
| 4 | Insulin promoter factor 1 | Rare | Reduced binding to the insulin gene promoter, reduced activation of insulin gene in response to hyperglycemia | Rare, pancreatic agenesis in homozygotes, less severe mutations result in mild diabetes | Yes | |
| 5 | Hepatocyte nuclear factor-1-beta | Rare | Pancreatic atrophy, renal dysplasia, renal cysts, renal insufficiency, hypomagnesemia | Yes | Insulin | |
| 6 | Neurogenic differentiation factor-1 | Rare | Pancreatic development | Yes | Insulin |
