Principals of Multifactorial Disease

Question 1

What is a multifactorial disease?

Answer 1

A disease which occurs in families more frequently than by chance alone, but show no clear pattern of inheritence

Question 2

What are some examples of multifactorial disease?

Answer 2

Hypertension
Stroke
Parkinson's
Alzheimer's
Diabetes

Question 3

What are polygenic traits and how do these relate to modifier genes?

Answer 3

Polygenic genes have a greater phenotypic impact when combined than they do separately which may be caused by modifier genes

Question 4

What are modifier genes?

Answer 4

Not associated with disease origin but once disease susceptibility is present, these genes modify the severity of the disease phenotype

Question 5

What is the threshold for a polygenic trait?

Answer 5

All individuals have a susceptibility to develop the trait, but a threshold must be reached before it is expressed. The normal distribution curve for families that have demonstrated the trait is further to the right the more family members are affected

Question 6

What are some rules for identifying a multifactorial disease?

Answer 6

Recurrence risk is proportional to the number of family members already affected
Recurrence risk is proportional to the severity of the condition of the proband
Frequency of disease in second degree relatives much lower than 1st degree but declines less rapidly for more distant relatives

Question 7

What is linkage analysis?

Answer 7

Looks for co-transmission of disease with polymorphisms of possible linked genetic markers

Question 8

What are genome-wide association studies?

Answer 8

Examines many common genetic variants in different individuals to see if any variant is associated with a trait (most commonly used)

Question 9

What are some of the advantages of identifying the genes involved with multifactorial disease?

Answer 9

Allows for risk prediction
Disease prevention strategies
Examine gene environment interactions
Understand disease pathophysiology

Question 10

What is personalised medicine?

Answer 10

The utilisation of individual genetic information and DNA based technologies to maintain health

Question 11

What is precision medicine?

Answer 11

Patient’s health information accessible to scientists so discoveries made in a lab could inform patient care