Complex Diseases and Pharmacogenetics Flashcards

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1
Q

What are the two different types of genetic diseases?

A

mendelian or complex

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2
Q

What is a mendelian disease/ trait?

A

A condition with clear mendelian inheritance patterns, caused by a single gene with limited environmental influence

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3
Q

What is an example of mendelian trait?

A

blood groups (ABO) (co-dominant but a single gene)

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4
Q

What is a complex disease/ trait?

A

A disease controlled by multiple genes, and where the phenotype is controlled by the interaction of many genes and the environment
quantitative traits e.g., height and weight

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5
Q

What is an example of a complex disease?

A

Cardiovascular disease

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6
Q

What are the causes of phenotypic differences?

A

Genetic differences
Shared environment
Unique environment

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7
Q

What is an SNP?

A

A single nucleotide polymorphism - DNA sequence variations that occur when a single nucleotide is changed
Can be in coding or non-coding region
Even in non-coding region it can have an effect

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8
Q

How do you examine association between SNP and disease risk?

A

Association studies- gene specific
hard to prove the SNP is linked to the disease- hard to find cases vs controls?
Hypothesis driven

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9
Q

What is the most common type of variation in a genome?

A

SNPs

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10
Q

What is meant by heritability?

A

It is an estimation of the genetic contribution to increased risk of disease

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11
Q

What are the two ways to measure heritability?

A

Twin Studies and Genome Wide Association studies

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12
Q

What are Genome Wide Association Studies?

A

Where you study the genomes of different people and look for an association between specific genetic variations and the different diseases that the people in the study have

Examine association SNPs and disease across entire genome

Hypothesis free

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13
Q

What are the benefits of GWAS?

A

Can identify SNP-variant associations I.e., risk loci for complex disease
Identify at risk individuals
Discovery of novel biological mechanisms
Inform drug discovery or repurposing
Identify ethnic differences

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14
Q

What are the limitations of GWAS?

A

Doesn’t identify casual variants- further testing required
Can’t identify all heritability (more rare variants won’t be noticed)
Threshold- won’t identify rare variants
Environmental influence- epigenetics

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15
Q

When are SNP’s said to be associated with certain conditions?

A

When SNPs are found to be more frequent in people with a disease compared to people without the disease

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16
Q

What specifically is GWAS lookin for?

A

Shared SNPs

17
Q

What is meant by missing heritability?

A

The gap between the association found by the GWAS and what is known about the heritability of the disease

18
Q

What are the 5 factors contributing to missing heritability?

A
  1. Rare SNPs
  2. Interactions are not taken into consideration
  3. Miscalculated estimation of heritability
  4. Diagnosis
  5. Low frequency variants with immediate effects
19
Q

What are dizygotic twins?

A

50% shared genetic component

20
Q

How do Twin studies work?

A

Since monozygotic twins share 100% of their genetic material, they can be analysed as any variation will be due to the environment, not genetics

21
Q

What is pharmacogenetics?

A

The study of differences in response to drugs due to genetic differences amongst people

22
Q

What can pharmacogenetics specifically help with?

A

The development of personalised medicine
Improve drug therapy and prescribing in the future

23
Q

What is the ideal scenario for a drug to work under?

A

Increased efficancy with decreased side effects

24
Q

What are the four classes of drug responses?

A

No effect
Recovery
Side effects
Death

25
Q

What is pharmacokinetics?

A

What the body does to the drug

26
Q

What is the order of pharmacokinetics?

A

absorption-> activation-> target -> inactivation-> excretion

After target it also goes to effect

activation can also be skipped

27
Q

What are the stages in pharmacokinetics that are concerning metabolism?

A

activation and inactivation
during activation it can be metabolised to be activated (aka prodrugs)

28
Q

Why is absorption important?

A

The majority of drugs are given orally
Majority of drugs are absorbed in small intestine
Use specific trnasporter proteins

29
Q

What is the definition of personalised medicine?

A

Tailoring treatment to patients depending on specific characteristics of their disease

30
Q

What are the most prevalent drug-metabolising enzymes?

A

Cytochrome P450 enzymes including CYP2D6 and CYP2C19

31
Q

How many phenotypes of CYP2D6?

A

4
ranging between 2 fully functional alleles and 2 non-functional alleles leading to ultra rapid metabolizer and poor metabolizer

32
Q

What is the best way to study Mendelian disease?

A

Family studies through pedigree charts

33
Q

Why might there be false positives when looking at over 10,000,000 SNPs?

A

Larger sample, more of a likelihood that diseases occur purely by chance

34
Q

Give some examples of the modifiable factors affecting CVD

A

Drinking habits

Eating habits

Smoking

High blood pressure

Sedentary lifestyle

35
Q

Give some examples of the non-modifiable factors affecting CVD

A

Age
Sex
genetics

36
Q

How do you examine association between SNP and disease risk?

A

Association studies- gene specific
hard to prove the SNP is linked to the disease- hard to find cases vs controls?
Hypothesis driven

37
Q

What are drug targets?

A

receptors
enzymes
ion channels
transport protein

I.e., beta-1 receptor (heart)= SG lower level of receptor activation

Hypertension- beta-blockade (slows heart rate/ force of contraction)