Aetiology and pathogenesis of diabetes mellitus:
A. Type I DM:
1. Genetic Susceptibility :
Certain genetic markers in the human leukocyte antigen (HLA) system have been
strongly linked with type I DM and the risk of developing diabetes is
substantially increased in the offspring of individuals diagnosed with diabetes.
2. Autoimmunity :
• Association with other autoimmune disease.
• Islet Cell Autoantibodies .
• Lymphocytic infiltration of islets ("Insulitis") .
3. Environmental Factors :
• Primary Autoimmunity .
• Viruses .
• Chemical Toxins .
• Cow’s Milk.
B. Type II DM:
1. Environmental Factors :
• Obesity.
• Sedentary Lifestyle.
• Age.
2. Genetic Factors :
• There is a greater than 905 concordance rate between monozygotic twins
if one has type II diabetes.
• It has been estimated that offspring of individuals with type II diabetes
have approximately a 15 % chance of developing the disease.
3. Insulin Deficiency :
• Insulin secretion may be normal in early stages.
• Pattern of insulin secretion changes.
• Accumulation of amylin in islets.
4. Insulin Resistance :
• Decrease in insulin receptors .
• Abnormal post-receptor signaling.
C. Secondary diabetes :
May arise from such conditions as endocrine disorders (e.g : Cushing's
syndrome), pancreatic disease, and the use of drugs that antagonize insulin(e.g
: Thiazide diuretics, adrenocorticosteriods).
A. Type I DM:
1. Genetic Susceptibility :
Certain genetic markers in the human leukocyte antigen (HLA) system have been
strongly linked with type I DM and the risk of developing diabetes is
substantially increased in the offspring of individuals diagnosed with diabetes.
2. Autoimmunity :
• Association with other autoimmune disease.
• Islet Cell Autoantibodies .
• Lymphocytic infiltration of islets ("Insulitis") .
3. Environmental Factors :
• Primary Autoimmunity .
• Viruses .
• Chemical Toxins .
• Cow’s Milk.
B. Type II DM:
1. Environmental Factors :
• Obesity.
• Sedentary Lifestyle.
• Age.
2. Genetic Factors :
• There is a greater than 905 concordance rate between monozygotic twins
if one has type II diabetes.
• It has been estimated that offspring of individuals with type II diabetes
have approximately a 15 % chance of developing the disease.
3. Insulin Deficiency :
• Insulin secretion may be normal in early stages.
• Pattern of insulin secretion changes.
• Accumulation of amylin in islets.
4. Insulin Resistance :
• Decrease in insulin receptors .
• Abnormal post-receptor signaling.
C. Secondary diabetes :
May arise from such conditions as endocrine disorders (e.g : Cushing's
syndrome), pancreatic disease, and the use of drugs that antagonize insulin(e.g
: Thiazide diuretics, adrenocorticosteriods).
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Diabetes Mellitus
