MODY Flashcards
What is monogenic diabetes?
Diabetes caused by a mutation in a single gene
What is the most common form of monogenic diabetes?
MODY - maturity onset diabetes of the young
What are the main types of monogenic diabetes?
MODY
Neonatal diabetes
When does neonatal diabetes present?
In the first 6 months of birth
Are MODY and neonatal diabetes caused by a defect in insulin secretion or insulin action?
Defect in insulin secretion
What are examples of disorders caused by a defect in insulin action (resistance)?
Donohue syndrome
Rabson Mendenhall syndrome
What is a cutaneous manifestation of hyperinsulinemia?
Acanthos nigricans
What are examples of defects in fat storage?
Congenital general lipodystrophy (CGL)
Familial partial lipodystrophy (FPLD)
How can defects of fat storage present?
Where patients have uneven fat distribution
E.g. little fat on arms and legs but fat in abdominal area
What pattern of inheritance is MODY?
Autosomal dominant
Is MODY insulin dependent or not?
Non-insulin dependent
What is the age of onset of MODY usually?
Before age 25
What are the three types of mutation that lead to MODY, and which is most common?
Glucokinase mutation
Transcription factor mutation (75%)
MODY x - unknown
How do glucokinase mutations lead to MODY?
Glucokinase phosphorylates glucose to glucose-6-phosphate, which is the rate limiting step and so affects glycolysis
How do transcriptions factor mutations lead to MODY?
Defects in transcription factor genes predominantly affect mitochondrial metabolism.
How do glucokinase mutations affect glucose levels?
More glucose is needed to begin insulin secretion but enough insulin can be produced if enough glucose is taken in as beta cells are otherwise normal
Blood glucose level is higher in patients but other than that patients do not have symptoms go hyperglycaemia
How do transcription factor mutations affect glucose levels?
Glucose starts of at normal levels but in the teens, glucose levels will start to increase, continuing to rise as age increases
What is the treatment for glucokinase mutation MODY?
Only diet - complications rare
What is the treatment for transcription factor mutation MODY?
Diet
Oral hypoglycaemic agents (OHA) - sulphonylureas
Insulin
What are the majority of neonatal diabetes caused by?
A mutation in the KATP channel
What is the treatment for neonatal diabetes?
Sulphonylureas
