Monogenic diabetes Flashcards
What is meant by monogenic diabetes?
Diabetes caused by a mutation in a single gene
What are the 2 mechanisms of monogenic diabetes?
Genetic defect in insulin secretion
Genetic defect in insulin action
What are some forms of monogenic defects in insulin secretion?
MODY (Maturity Onset Diabetes of the Young)
Neonatal diabetes
What are some forms of monogenic defects in insulin action?
- Donoghue syndrome
- Rabson Mendenhall syndrome
- Type A insulin resistance
What is a possible condition caused by hyperinsulinaemia?
Acanthosis nigricans
What is MODY?
This is an autosomal dominant form of monogenic diabetes causing a defect in insulin production
When does MODY usually occur?
Before 25 years old
What are the 2 types of MODY?
Glucokinase defects
Transcription factor defects
Describe the physiology of glucokinase?
The black line shows the normal glucokinase activity The normal fasting glucose is 5mmol/L]
As glucose levels increase, glucokinase activity increases quickly to secrete more insulin
As glucose levels decrease, gluckinase activity decreases quickly to secrete less insulin
What happens in glucokinase defect type MODY?
In glucokinase mutations, the blue line occurs, in which the fasting glucose rate is increased, so low level and high level responses are still performed, just at a higher level
When do glucokinase defects usually present?
At birth
When do transcription factor defects usually present?
In adolescence or young adulthood
How are glucokinase defects managed?
Diet alone
How are transcription factor defects managed?
- 1/3rd - Diet
- 1/3rd - OHA(Oral hypoglycaemic agents)
- 1/3rd - Insulin
Give an example of a transcription factor defect?
HNF-1a (Highly sensitive to sulphonylureas)
