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?

A

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

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3
Q

What is a complex disease?

A

A disease controlled by multiple genes, and and the environment e.g CVD

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4
Q

Can a disease explicitly be Mendelian or complex?

A

It is difficult to say if a disease is one or the other. E.g SCD is caused by point mutation in B-globin chain of haemoglogin. However condition is exacerbated by environmental factors.

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5
Q

What is an SNP?

A

A single nucleotide polymorphism - DNA sequence variations that occur when a single nucleotide is changed

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6
Q

where do SNPs occur?

A

in coding or non-coding regions

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7
Q

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

A

SNPs

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8
Q

What is meant by heritability?

A

It is an estimation of the genetic contribution to a disease

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9
Q

what are the causes of phenotypic differences?

A
  1. genetic differences
  2. shared environment
  3. Unique environment
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10
Q

What are the two ways to measure heritability?

A

Twin Studies and Genome Wide Association studies

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11
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

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12
Q

What are the downsides of GWAS?

A

You need a very large sample size

Mass testing is required which needs money and qualified people

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13
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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14
Q

What specifically is GWAS lookin for?

A

Shared SNPs

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15
Q

what is whole genome sequencing (WGS)?

A

entire genome scrutinised - every SNP can be identified

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16
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

17
Q

What is pharmacogenetics?

A

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

18
Q

what is the aim of Pharmacogenomics?

A

improve drug therapy and prescribing in the future

19
Q

What are the 4 possible outcomes of drugs on our body?

A
  1. It can be non-toxic and beneficial
  2. non -Toxic and non -beneficial
  3. Toxic and beneficial
  4. Toxic and non-beneficial
20
Q

genetic variants in drug-related genes are v.rare. What are the consequences of this in clinical trials?

A

They are unlikely to be spotted in clinical trials (need huge population)

21
Q

what is Pharmacokinetics?

A

what the body does to the drug

22
Q

explain simplistically the process of pharmacokinetics

A
  1. drug absorbed
  2. activated.
  3. distributed to target site
  4. has its effects
  5. metabolised so deactivates
  6. excreted
23
Q

What can pharmacogenetics specifically help with?

A

The development of personalised medicine

24
Q

where are the majority of drugs absorbed if taken orally? How are they absorbed?

A

small intestine and use specific transporter proteins;

25
Q

why aren’t some drugs absorbed in small intestine?

A

some transporter proteins chuck them out (enhance removal)

26
Q

what is P-GP?

A

a type of transporter protein found in small intestine that prevents absorption of digoxin and fexafenodine

27
Q

what are the substrates for P-GP?

A

digoxin/fexafenodine

28
Q

describe how alcohol is metabolised?

A
  • ethanol is converted into toxic acetaldehyde via alcohol dehydrogenase
  • acetaldehyde is converted into non-toxic acetate (via alcohol dehydrogenase)
29
Q

How can SNPs affect alcohol metabolism?

A

Either:
1. Build up of ethanol
2. Build up of toxic acetaldehyde

(caused by inactivation of alcohol dehydrogenase via SNPs)

30
Q

which drug needs to be metabolised to be activated? what is the active form?

A

codeine, which is converted into morphine

31
Q

which gene is heavily involved in metabolising drugs?

A

CYP2D6

32
Q

why is there huge variation in how drugs are metabolised?

A

there are over 100 variants of CYP2D6

33
Q

what makes you a ultra rapid metaboliser?

A

if you have two fully active alleles of the CYP2D6

34
Q

what kind of metabolisers are most people? what does this mean?

A

extensive metaboliser (75-80%). Contain at least one fully active alleles

35
Q

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

A

Increased efficancy with decreased side effects

36
Q

What is the best way to study Mendelian disease?

A

Family studies through pedigree charts