Type 1 diabetes (β-cell destruction, usually leading to absolute insulin deficiency)

• Immune mediated

• Idiopathic

Type 2 diabetes (may range from predominantly insulin resistance with relative insulin deficiency to a predominantly secretory defect with insulin resistance)

Other specific types

• Genetic defects of β-cell function

  1. Chromosome 12, HNF-1α (MODY3)

  2. Chromosome 7, glucokinase (MODY2)

  3. Chromosome 20, HNF-4α (MODY1)

  4. Chromosome 13, insulin promoter factor-1 (IPF-1; MODY4)

  5. Chromosome 17, HNF-1β (MODY5)

  6. Chromosome 2, NeuroD1 (MODY6)

  7. Mitochondrial DNA

  8. Others

• Genetic defects in insulin action

  1. Type A insulin resistance

  2. Leprechaunism

  3. Rabson-Mendenhall syndrome

  4. Lipoatrophic diabetes

  5. Others

• Diseases of the exocrine pancreas

  1. Pancreatitis

  2. Trauma/pancreatectomy

  3. Neoplasia

  4. Cystic fibrosis

  5. Hemochromatosis

  6. Fibrocalculous pancreatopathy

  7. Others

• Endocrinopathies

  1. Acromegaly

  2. Cushing's syndrome

  3. Glucagonoma

  4. Pheochromocytoma

  5. Hyperthyroidism

  6. Somatostatinoma

  7. Aldosteronoma

  8. Others

• Drug or chemical induced

  1. Vacor

  2. Pentamidine

  3. Nicotinic acid

  4. Glucocorticoids

  5. Thyroid hormone

  6. Diazoxide

  7. β-adrenergic agonists

  8. Thiazides

  9. Dilantin

  10. γ-Interferon

  11. Others

• Infections

  1. Congenital rubella

  2. Cytomegalovirus

  3. Others

• Uncommon forms of immune-mediated diabetes

  1. “Stiff-man” syndrome

  2. Anti-insulin receptor antibodies

  3. Others

• Other genetic syndromes sometimes associated with diabetes

  1. Down syndrome

  2. Klinefelter syndrome

  3. Turner syndrome

  4. Wolfram syndrome

  5. Friedreich ataxia

  6. Huntington chorea

  7. Laurence-Moon-Biedl syndrome

  8. Myotonic dystrophy

  9. Porphyria

  10. Prader-Willi syndrome

  11. Others

Gestational diabetes mellitus