Pharmacogenetics

Question 1

How many chromosome does a human have?

Answer 1

46 in total
2 sex chromosome
22 pairs of autosomal chromosomes

Question 2

How many haploid DNA base pairs does a human have?

Answer 2

3 billion

Question 3

How many diploid DNA base pairs does a human have?

Answer 3

6 billion

Question 4

Explain genotype vs phenotype

Answer 4

Genotype = organism's genetic makeup that includes all alleles situated on homologous chromosomes
Phenotype = observable characteristics of an organism resulting from the interaction of its genotype with the environment

Question 5

Define pharmacogenetics

Answer 5

The study of variability in drug response due to heredity

Question 6

Name the steps in phase I metabolism

Answer 6

Oxidation
Hydroxylation
Reduction
Hydrolysis

Question 7

What is phase II metabolism?

Answer 7

Conjugation

Question 8

Which drugs are metabolised by n-acetyltransferase?

Answer 8

Isoniazid
Sulfonamids
Procainamide
Hydralazine
Caffeine

Question 9

Name the two functions of the CYP250 system

Answer 9

1. Formation of cholesterol, steroids and arachidonic acid metabolites
2. Metabolism and detoxification of xenobiotics

Question 10

Which CYP450 gene metabolizes the majority of drugs?

Answer 10

CYP3A4/5 > CYP2D6 > CYP2C8/9

Question 11

Which CYP450 gene metabolizes TCAs, SSRIs and antipsychotics?

Answer 11

CYP2D6

Question 12

Which CYP450 gene metabolizes codeine?

Answer 12

CYP2D6 -> morphine

Question 13

Which CYP450 gene metabolizes tramadol?

Answer 13

CYP2D6 -> O-desmethyltramadol (higher affinity for u opioid receptor)

Question 14

Which CYP450 gene metabolizes proton pump inhibitors?

Answer 14

CYP2C19

Question 15

Which CYP450 gene metabolizes proguanil?

Answer 15

CYP2C19 -> cycloguanil

Question 16

Which CYP450 gene metabolizes clopidogrel?

Answer 16

CYP2C19

Question 17

Which drugs inhibit CYP2C9?

Answer 17

INH

Question 18

Which drugs induce CYP2C9?

Answer 18

Ritonavir

Nelfinavir

Question 19

Which CYP450 gene metabolizes wafarin?

Answer 19

CYP2C19

Question 20

What does high expression of HER2 indicated?

Answer 20

Better response to herceptin therapy

Question 21

What is the result of a thiopurine s-methyltransferase deficiency?

Answer 21

Haematopoetic toxicity with 6-mercaptopurine

Question 22

What is the result of a dihydropyrimidine dehydrogenase deficiency?

Answer 22

Neurotoxicity with 5-fluorouracil

Question 23

What is the result of a thymidylate synthase overexpression?

Answer 23

Cancer resistance

Question 24

Which ARV has severe side effects in some white males?

Answer 24

Abacavir

Question 25

Which CYP450 gene metabolizses ARVs?

Answer 25

CYP3A4