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MCD- Genetics- Laz > Diabetes > Flashcards

Flashcards in Diabetes Deck (17):
1

What causes MODY (maturity onset diabetes of the young)?

Autosomal dominant mutation
HNF 4alpha
HNF 1alpha (most common)
Glucokinase (second most common)

2

what is HNF 1alpha?

Transcription factor that stimulates insulin production
Mutation = insulin production decreases in adulthood when its function naturally deteriorates
(appears in teenage years)

3

Treatment for HNF 1alpha MODY

Metformin = cells more sensitive to insulin
Sypulphonylurea = stimulates pancreas to produce more insulin by forcing potassium channel to close

4

What is glucokinase MODY?

Enzyme converts glucose - G6P
Higher glucose conc needed for insulin secretion to occur
Patients have stable mild hyperglycaemia
not associated with long term complications

5

HNF4alpha MODY

Similar to HNF1alpha but rarer
Older onset
Low renal glucose threshold

6

HNF1beta MODY

Renal cysts and diabetes
Genital tract mutation

7

What mutation causes Permanent neonatal diabetes

KNCJ11
1 in 400000 births
Diabetes in first 6 months

8

How does the mutation cause permanent neonatal diabetes

KNCJ11 causes K+ channel to open when ATP is made by respiration
This means membrane cannot be depolarised and insulin not released

9

How do sulphonylureas treat PND?

Close the K+ channel so signal sent to insulin to be released

10

What is Sanger sequencing?

Sequences all exons of one single gene
Used to identify unknown mutation
Very precise
But expensive, time consuming, poorly automated

11

What is next generation sequencing?

Sequences multiple genes
Used to identify mutations in multiple genes for heterogenous phenotypes
Cost effective
Not very accurate, needs a lot of data to sequence

12

What is pathogenicity?

Ability for an organism to cause disease

13

Symptoms of maternally inherited diabetes and deafness (MIDD)

Young onset deafness
High lactate
Muscle aches
Short stature

14

What is polygenic diabetes?

Type 1 and 2
There must be a second hit to get condition e.g. environmental

15

What is GWAS?

Genome wide association study
Study to see if diseases is associated with single nucleotide polymorphism

16

Why could be causing the diabetes T2 epidemic?

Copy number variation (deletion and duplication of genes)= copies of the same gene

17

how is insulin secreted from a beta cell?

ATP sensitive potassium channel
detects ATP from glycolysis
potassium channel closes
membrane depolarises
calcium enters
insulin vesicles released