Genetic Risks

Question 1

What are the aims of using genetics to assist population health?

Answer 1

• Genetic screening can detect individuals at increased risk of disease.
• Genetic information will promote a healthy lifestyle (increases life longevity and quality of life)
• Establish clear diagnostic boundaries
• Knowing genetic risk will prevent disease onset
• Develop new and more ‘targeted’ medications
• Personalised treatment plans that will work for your genes

Question 2

What is DNA composed of?

Answer 2

• a deoxyribose sugar
• a base

Question 3

What is a chromosome?

Answer 3

A continuous piece of DNA.

Question 4

How many genes do humans have?

Answer 4

20,000 - 30,000

Question 5

What are genes’ purposes?

Answer 5

To code for specific proteins

Question 6

List a few types of genetic mutation.

Answer 6

• Duplication of a gene
• Deletion of a gene
• Inversion of a gene

Question 7

What is a single-gene disease?

Answer 7

Inherited diseases that are caused by a mutation in a single gene

Question 8

Give an example of a single gene disease and describe it.

Answer 8

Cystic Fibrosis.
A genetic disease that causes long-term lung infections and limits the ability to breathe over time, is caused by variants in the cystic fibrosis transmembrane conductance regulator(CFTR)gene on chromosome 7.

Question 9

What is a complex (polygenic) disease?

Answer 9

Diseases that occur as a result of many genomic variants, paired with environmental influences such as diet and smoking.

Question 10

Give an example of a complex disease.

Answer 10

Coronary artery disease.

Question 11

Define ‘genetic predisposition’.

Answer 11

An increased likelihood of developing a particular disease based on a person’s genetic makeup.

Question 12

List four types of methods used to measure population health using genetics.

Answer 12

• Family based studies
• Linkage studies
• Expression
• Association analyses

Question 13

What is the purpose of family based studies?

Answer 13

To identify how heritable an outcome is.

Question 14

How do researchers carry out family based studies?

Answer 14

• Twin studies which are conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders.
• Adoption studies are used to estimate the degree to which variation in a trait is due to environmental and genetic influences.

Question 15

What is linkage analysis?

Answer 15

A statistical method for mapping the genes for heritable traits to their chromosome locations.

Question 16

What is the candidate-gene approach?

Answer 16

Depends on a set of genetic markers based on a prior hypothesis about the role of a selected gene, or a group of pathway-related genes, on a phenotype.

Question 17

List a few difficulties with succeeding in candidate-gene approaches.

Answer 17

1) small sample sizes
2) inadequate or loose statistical thresholds
3) inefficient number of genetic markers tested
4) people dropping out of the study

Question 18

List the issues with the Genome-Wide Association Studies (GWAS).

Answer 18

Not representative of those who are not of European ancestry.

Question 19

What is a polygenic score (PGS)?

Answer 19

PSG condenses condenses information from many of a person’s genetic variants into a score that measures the individual’s genetic predisposition to specific diseases or complex traits.

Question 20

What does SNP stand for?

Answer 20

Single-nucleotide polymorphisms

Question 21

How are SNPs used to predict disease risk?

Answer 21

Merging information across thousands or even millions of SNPs can be useful in predicting disease risk.