Trigger 10: Mendelian randomisation Flashcards Preview

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Flashcards in Trigger 10: Mendelian randomisation Deck (23)
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1
Q

mendelian randomisation use

A

previously collected data e.g. GWAS (biobanks)

2
Q

mendelian randomisation simple

A

used to strengthen causal inference

3
Q

epidemiologists are interesting in understandings

A

factors which relate to health and disease e.g. smokers dye younger than non-smokers

4
Q

main issue relates to

A

determining cause and effect due to confounders e.g. smokers are more likely to drink more and have less healthy diets

5
Q

an RCT where 50,000 people are randomised to smoke ad 50,000 are randomised to not smoke

A

would prove a cause and effect relation - however would not be ethical or practical

6
Q

our genes influence how much

A

we eat, drink, smoke and eat

7
Q

genetic influences are not effected by

A

Confounding factors –> anything you may choose to do or not to do e.g. smoke

8
Q

mendelian randomisation study can tell us

A

about which factors cause disease

9
Q

example of MR study

A

heavy smokers may carry specific genes and die younger than the average individual, but mendelian randomisation also show that non-smokers with the same genes have normal life expectancy - showing that smoking causes shorter life expectancy

10
Q

MR uses a ……. approach

A

statistical approach, which lies to determine if exposure to certain factors causes certain diseases - unbiased estimate

11
Q

example of cause and effect with confounders

A

e.g. if you looked at correlations you may see that people who drink more get lung cancer, suggesting that alcohol causes lung cancer. - however this is confounded by the fact that those who drink more also smoke more - therefore smoking is causing individuals to drink more - smoking could also be causing cancer

12
Q

draw flow chart which shows how cause and effect can be confounded

A
13
Q

to find genes which cause common traits what sort of studies are used

A

genetic association studies e.g. MR

14
Q

genetic association studies correlate

A

commo genetic variants (SNPs) with disease prevalence

15
Q

geen variants are present

A

more frequently in people with disease than control- providing proabbility of disease status

16
Q

which statistical tests can be used to see if there is a statistical difference between cases and controls relating to specific genotypes

A

Chi-sq

17
Q

gene vairants present more freuquently in

A

cases than control

18
Q

where you are in the BMI range ina given popualtion at any time is

A

>30-40% genetic

19
Q

Obesity GWAS have shown that …. regions of the human genome are associated with BMI

A

97 regions

20
Q

Obesity GWAS have found common genetic variants hit loci containing monogeneic obesity genes like

A

SH2B1

BDNF

POMC

MCDR

21
Q

SH2B1

BDNF

POMC

MC4R

are mutations which affect

A

appetite

22
Q

genes indeitifed by obesity GWAS are more liekly to be expressed it he

A

CNS

23
Q

which pathways in the CNS are affected

A

hippocampus

limbic system

hypothalamus