Complex disease and pharmacogenetics (23)

Question 1

What is a Mendelian trait?

monogenic

Answer 1

• controlled by a single gene
• inheritance follows Mendel’s principles
  (the one we use to draw punnet squares)
• e.g. earlobe attachment, ABO blood group, sickle cell anaemia

Question 2

What is a Complex trait?

Answer 2

• controlled by multiple genes + the effect of the environment
• e.g. hair, skin, eye colour, height, weight, personality, diabetes, mental health diseases

Question 3

What is a Single Nucleotide Polymorphism (SNP)?

READ AROUND_ WHAT

Answer 3

DNA sequence variations that occur when a single nucleotide is changed
- most common form of variation in the human genome

Question 4

What is a risk allele?

READ AROUND

Answer 4

the allele that is more frequent amongst disease patients

Question 5

What is the idea of missing heritability?

Answer 5

the gap between what is known about the heritability (determined by twin studies) of a disease and what is actually found by Genome Wide Association Studies (GWAS)
e.g. if a phenotype has a known heritability of 40%, the GWAS loci may still be less than 5-10%

Question 6

Reasons suggested for missing heritability

Answer 6

• rare variants
• low frequency variants with intermediate effects
• interactions
• miscalculated estimation of heritability
• diagnosis (bad accuracy and precision)

Question 7

What is pharmacogenetics?

Answer 7

the study of variability in drug response
- due to genetic differences
N.B. king’s essay- antidepressants

Question 8

What is heritability?

Answer 8

the proportion of variation in the population that is explained by genetics and inheritance rather than environmental factors

Question 9

What is personalised medicine?

Answer 9

tailoring treatment to patients depending on the specific characteristics of their disease