Lec 1

Question 1

What’s the deffinition if pharmacogenetics

Answer 1

The study of genetic variation in humans that gives rise to different responses to drugs

Question 2

What is the deffinition of pharmacogenomics

Answer 2

The application of genomic technologies for the optimisation of drug therapies soda pets to an individuals genetic make up

Both terms apply to the study of how an individual genetic make up affects the bodies response to a drug

Question 3

What is discrimination

Answer 3

Recognition and understanding of the difference between one thing and another

Genetically different people may have different outcomes to the same actions
The same patient under a different environment may have a different outcome

Question 4

DNA facts

Answer 4

23 Pairs of chromosomes (number 1 is the biggest)
DNA tightly wrapped around proteins for efficient packing
3 billion base pairs
20,000 -25,000 genes
We are all 99.9% genetically identical
23rd pair are the sex chromosomes, X+Y

Question 5

What are the main classes of genetic diseases

Answer 5

Dominant: Huntington’s disease
Recessive: cystic fibrosis
X linked disease: haemophillia
Chromosomal diseases: Down’s syndrome has an extra copy of chromosome 21
Susceptibility to many diseases has a genetic component but is less obvious from patterns of inheritance
Multiple genes may interact with the environment to play apart

Question 6

State some genes which can cause disease

Answer 6

app-E4 (variant of alipoprotein E gene) linked to late onset Alzheimer’s disease

Factor V Leiden- mutation in coagulation factor V, increased risk of VTE

Question 7

Human genome project (HGP)

Answer 7

The human genome project commended in 1990
1st sequence completed in 2003
Aim of the project is to characterise genes and establish their function in health and disease

Question 8

What is the international HapMap project

Answer 8

Haplotype Map project is creating a database of common human genetic polymorphisms
Taken from a range of individuals from different populations

Facilities discovery of genetic variation involved in more common diseases and responses to drugs

Question 9

What is the goal of pharmacogenomics

Answer 9

Individuals respond differently to drugs
The genetic differences contribute to the variation in drug responses observed amongst individuals (environment, age, diet, lifestyle and health effect response)

Drugs may one day be tailor- made to an individuals genetic make up

Question 10

What are SNPs

Answer 10

Single nucleotide polymorphism (SNP) are substitutional is an individual base along a chromosome
SNPs occur on average somewhere between every 1/100 - 1/1000 base pairs m
Over 1.4 mil SNPs were identified in the HGP, 60,000 of which were in coding regions
SNPs are most likely to make a difference if they are in a coding region or gene regulating region such as promoter or transcription factor binding site

Question 11

What can SNPs effect

Answer 11

Drug metabolism enzymes
Drug transporters which regulated the absorption distributing and excretion of drugs
Drug targets
Disease or treatment modifying genes (such as genetic variation in risk of side effects)

Question 12

State some drug metabolising enzymes

Answer 12

CYP2C9- anticoagulation effects of warfarin
CYP2C19- peptic ulcers response to omeprazole
CYP2D6- antidepressant toxicity, codine analgesia
Dihydropyrimidine dehydrogenase- neurotoxicity to flurouracil

Question 13

State some drug targets

Answer 13

ACE- BP reduction, lipid changes
B2- adrenergic receptor- bronchodilators
Dopamine receptor- antipsychotic response
Serotonin transporter- antidepressant

Question 14

State some genetic polymorphism that effect drug effects

Answer 14

Disease or treatment modifying agents:
APOE- response to statin in atherosclorosis progression, also Alzheimer’s disease
HLA- increase risk of hypersensitivity in response to abacavir
Prothrombin and factor V- risk of deep vein thrombosis in response to oral contraceptives

Question 15

What is TPMT

Answer 15

Thiopurine-S-Methyl Transferase

A monogenic trait that effects drug metabolism
It is the most important inactivation pathway for mercaptopurine and azathiopurine in haematopoietic tissue
These drugs are used as immunosuppressants and treatment of neoplasia

Question 16

TPMT facts and figures

Answer 16

TMPT is highly variable
90% of people= high activity
10% of people= intermediate activity

0.3% of people= Low or no activity

TMPT deficiency can lead to haematological toxicity in normal doses

Question 17

How do we identify relevant SNPs

Answer 17

PCR 
qPCR 
FISH(fluorescent in soft hybridisation) 
Immunohistochemistry 
Array comparative hybridisation 
PCR followed by sequencing

Question 18

Describe immunohistochemistry

Answer 18

Design an antibody that will have a receptor site complementary to the protein of interest
We are limited to proteins on the outside of the cells because to look inside we have to kill them
1) produce a primary antibody which will bind to the target protein 2) then add a secondary antibody which will bind to the primary 3) we then place a tag onto the secondary antibody so when it binds it lights up

Question 19

Describe FISH

FLORESCENT IN SITU HYBRIDSATION

Answer 19

used more for identifying areas on chromosomes
Instead of placing a probe onto a protein it is placed on a DNA, with a florescent marker
This allows us to recognise how much of a gene is present in a chromosome or if there is any at all and the implication of that

Question 20

Describe PCR

polymerase chain reaction

Answer 20

2 strands of DNA double helix physically seperated
2 DNA strands become templates for DNA polymerase to selectively amplify target DNA
1) denature stage 94-95’C
2) annealing stage 50-56’C (primer is added)
3) extending stage 72’C

This multiplies exponentially the amount of DNA

Question 21

Describe qPCR

Quantative PCR

Answer 21

Real time PCR
Amplifies and simaltaneously quantifies target DNA molecules
Target DNA strands is hybridised with probe
Measure the amplification of the DNA

We basically no how much

Question 22

Describe micro-array

Answer 22

DNA strands are immobalised on a probe
Go through PCR and apply to micro-array
Genes of interest will stick
Add florescent probe and scan

+ve: we can apply it to the entire genome
-ve: computing power to process this is huge and time taken to process this

Question 23

Ethnic drugs the case of BiDil

Answer 23

Some drugs only work in people from certain ethnic backgrounds
BiDil is a fixed dose combination of isosorbide dinitrate and salazine

Treatment of congestive HF
Originally reflected by the FDA in 1997, when trials of Caucasian showed no effect
Approved in 2005 for African Americans only
Mortality reduced by 43%
African Americans respond less well to ACEI