📌 Related Subjects:
Type 1 DM
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Type 2 DM
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Diabetes in Pregnancy
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HbA1c
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Diabetic Ketoacidosis (DKA) Adults
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Hyperglycaemic Hyperosmolar State (HHS)
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Diabetic Nephropathy
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Diabetic Retinopathy
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Diabetic Neuropathy
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Diabetic Amyotrophy
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Maturity Onset Diabetes of the Young (MODY)
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Diabetes: Complications
🧬 Maturity Onset Diabetes of the Young (MODY) is a monogenic form of diabetes caused by a mutation in a single gene.
It usually presents before the age of 25, follows an autosomal dominant inheritance pattern, and is frequently misdiagnosed as Type 1 or Type 2 diabetes.
📖 About
- 👶 Age of Onset: Typically before 25 years, but can occur later.
- 🧬 Inheritance: Autosomal dominant – ~50% of children of an affected parent develop MODY.
- 💉 Insulin Production: Preserved (unlike T1DM), but secretion may decline in some subtypes.
- 💊 Treatment: Often responsive to oral hypoglycaemics (especially sulfonylureas) instead of insulin.
🔢 Types
- MODY 1 (HNF4A mutation): Mild hyperglycaemia, good response to sulfonylureas.
- MODY 2 (GCK mutation): Stable mild fasting hyperglycaemia from birth, usually no treatment needed.
- MODY 3 (HNF1A mutation): Most common type; progressive decline in insulin secretion, sulfonylurea-sensitive.
- MODY 5 (HNF1B mutation): Associated with renal abnormalities and extra-pancreatic features; often needs insulin therapy.
🌍 International Definitions (WHO)
- ✅ Normal: Fasting glucose <6.1 mmol/L (<110 mg/dL) and 2-hr OGTT <7.8 mmol/L (<140 mg/dL).
- ⚠️ Impaired Glucose Tolerance (IGT): 2-hr OGTT 7.8–11 mmol/L (140–199 mg/dL).
- 💉 Diabetes: Fasting glucose ≥7.0 mmol/L (≥126 mg/dL) OR random ≥11.1 mmol/L (≥200 mg/dL) + symptoms.
🧪 Diagnosis
- Genetic Testing: Gold standard. Identifies the exact mutation → guides treatment & family screening.
- Clinical Suspicion: Consider in young patients with diabetes + strong family history, especially if atypical for T1DM (no ketoacidosis, still producing insulin) or T2DM (not obese, no metabolic syndrome).
💊 Treatment
- MODY 1 & MODY 3: Sulfonylureas highly effective, sometimes lifelong.
- MODY 2: Usually no treatment required (benign mild hyperglycaemia).
- MODY 5: May require insulin; also monitor & manage renal disease and other systemic issues.
