Types of Diabetes

Types of Diabetes

• Diabetes mellitus is a group of metabolic disorders sharing the common feature of hyperglycemia

• Hyperglycemia can result due to

  • Defects in insulin secretion

  • Defects in insulin action

  • Both

• Diabetes is classified into

• • Type 1 Diabetes ( β- cell destruction leading to absolute insulin deficiency)

    • Immune mediated

    • Idiopathic

  • Type 2 Diabetes (Combination of insulin resistance and β- cell dysfunction)

  • Genetic defects in β cell function

    • Maturity onset diabetes of the young (MODY) caused by mutations in

      • Hepatocyte nuclear factor 4α (HNF 4α) – MODY 1

      • Glucokinase – MODY 2

      • Hepatocyte nuclear factor 1α (HNF 1α) – MODY 3

      • Pancreatic and duodenal homeobox 1 (PDX1) – MODY 4

      • Hepatocyte nuclear factor 1β (HNF 1β) – MODY 5

      • Neurogenic differentiation factor 1 (NEUROD 1) – MODY 6

    • Neonatal diabetes (activating mutations in KCNJ11 adn ABCC8, encoding Kir6.2 and SUR1, respectively

    • Maternally inherited diabetes and deafness (MIDD) due to mitochondrial DNA mutations (m.3243→G)

    • Defects in proinsulin conversion

    • Insulin gene mutation

  • Genetic defects in insulin action 

    • Type A insulin resistance

    • Lipoatrophic diabetes

  • Exocrine pancreatic defects

    • Chronic pancreatitis

    • Pancreatectomy/trauma

    • Neoplasia

    • Cystic fibrosis

    • Hemochromatosis

    • Fibrocalculous pancreatopathy

  • Endocrinopathies

    • Acromegaly

    • Cushing syndrome

    • Hyperthyroidism

    • Pheochromocytoma

    • Glucagonoma

  • Infections

    • Cytomegalovirus

    • Coxsackie B virus

    • Congenital rubella

  • Drugs

    • Glucocorticoids

    • Thyroid hormone

    • Interferon – α

    • Protease inhibitors

    • β- Adrenergic agonists

    • Thiazides

    • Nicotinic acid

    • Phenytoin

    • Vacor

  • Genetic syndromes associated with diabetes

    • Downs syndrome

    • Klinefelter syndrome

    • Turner syndrome

    • Prader-Willi syndrome

  • Gestational diabetes mellitus

Reference

• American Diabetes Association: Position statement from the American Diabetes Association on the diagnosis and classification of diabetes mellitus. Diabetes Care 31 (Suppl. 1):S55-S60,2008

• Anirban Maitra. The Endocrine system.In: Robbins and Cotran Pathologic basis of disease.9th edition.volume II.chapter 24. pp 1073-1141.