MODY

Question 1

What is monogenic diabetes?

Answer 1

Diabetes caused by a mutation in a single gene

Question 2

What is the most common form of monogenic diabetes?

Answer 2

MODY - maturity onset diabetes of the young

Question 3

What are the main types of monogenic diabetes?

Answer 3

MODY

Neonatal diabetes

Question 4

When does neonatal diabetes present?

Answer 4

In the first 6 months of birth

Question 5

Are MODY and neonatal diabetes caused by a defect in insulin secretion or insulin action?

Answer 5

Defect in insulin secretion

Question 6

What are examples of disorders caused by a defect in insulin action (resistance)?

Answer 6

Donohue syndrome

Rabson Mendenhall syndrome

Question 7

What is a cutaneous manifestation of hyperinsulinemia?

Answer 7

Acanthos nigricans

Question 8

What are examples of defects in fat storage?

Answer 8

Congenital general lipodystrophy (CGL)

Familial partial lipodystrophy (FPLD)

Question 9

How can defects of fat storage present?

Answer 9

Where patients have uneven fat distribution

E.g. little fat on arms and legs but fat in abdominal area

Question 10

What pattern of inheritance is MODY?

Answer 10

Autosomal dominant

Question 11

Is MODY insulin dependent or not?

Answer 11

Non-insulin dependent

Question 12

What is the age of onset of MODY usually?

Answer 12

Before age 25

Question 13

What are the three types of mutation that lead to MODY, and which is most common?

Answer 13

Glucokinase mutation
Transcription factor mutation (75%)
MODY x - unknown

Question 14

How do glucokinase mutations lead to MODY?

Answer 14

Glucokinase phosphorylates glucose to glucose-6-phosphate, which is the rate limiting step and so affects glycolysis

Question 15

How do transcriptions factor mutations lead to MODY?

Answer 15

Defects in transcription factor genes predominantly affect mitochondrial metabolism.

Question 16

How do glucokinase mutations affect glucose levels?

Answer 16

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

Question 17

How do transcription factor mutations affect glucose levels?

Answer 17

Glucose starts of at normal levels but in the teens, glucose levels will start to increase, continuing to rise as age increases

Question 18

What is the treatment for glucokinase mutation MODY?

Answer 18

Only diet - complications rare

Question 19

What is the treatment for transcription factor mutation MODY?

Answer 19

Diet
Oral hypoglycaemic agents (OHA) - sulphonylureas
Insulin

Question 20

What are the majority of neonatal diabetes caused by?

Answer 20

A mutation in the KATP channel

Question 21

What is the treatment for neonatal diabetes?

Answer 21

Sulphonylureas