Multifactorial diseases

Question 1

Examples of Multifactorial Diseases

Answer 1

diabetes, cardiovascular diseases, dementia, and other quite commonly occurring diseases

Question 2

What is a multifactorial disease?

Answer 2

diseases that arise due to a combination of genetic and environmental factors. They have complex etiology (=caused by multiple factors working together rather than a single gene or environmental factor).

Question 3

Some characteristic of multifactorial diseases

Answer 3

These diseases are more common than single-gene disorders, and they can be challenging to diagnose and treat due to their complex nature.

Question 4

How do multifactorial diseases work? Give an example.

Answer 4

A person may have a genetic predisposition to heart disease, but environmental factors such as smoking, a high-fat diet, and lack of exercise can also increase their risk of developing the disease

Question 5

How can you treat multifactorial diseases?

Answer 5

Management of these diseases may involve lifestyle modifications, medication, and other interventions aimed at minimizing the impact of genetic and environmental risk factors.

Question 6

Liability

Answer 6

individual’s genetic predisposition or susceptibility to a particular disease or condition

Question 7

Additive effects

Answer 7

combined influence of multiple genetic and environmental factors that contribute to the overall risk or susceptibility of developing a particular disease or condition

Question 8

Define syndromic disorder and give an example

Answer 8

It is a genetic disorder in which the affected individual experiences a combination of symptoms that occur together and are characteristic of a specific syndrome.
Example: you are not only deaf, but you also have other symptoms/problems (Usher syndrome: + visual problems)

Question 9

Define nonsyndromic disorder and give an example

Answer 9

It is a genetic disorder in which the affected individual experiences a specific trait or condition, such as deafness, without any other associated features or symptoms.
It typically involves a single gene. In nonsyndromic hearing loss, for instance, the affected individual experiences hearing impairment without any other associated abnormalities. These disorders are characterized by the absence of additional features or abnormalities beyond the primary trait or condition.

Question 10

Gaussian (normal) distribution

Answer 10

If we look at a large population and how different traits are distributed in that population (IQ, heights, body mass etc), we will get ….

Question 11

Mendelian genetics

Answer 11

(Gregor Mendel - 19th century) - It describes how genetic traits are inherited from one generation to the next.

Question 12

What are the principles of Mendelian genetics?

Answer 12

Law of Segregation, Law of Dominance, Law of Independent Assortment

Question 13

Law of Segregation

Answer 13

This law states that during the formation of gametes (sperm and egg), the two alleles (versions of a gene) for a trait separate from each other so that each gamete receives only one allele.

Question 14

Law of Independent Assortment

Answer 14

This law states that the inheritance of one trait is not influenced by the inheritance of another trait. This is because the genes for different traits are located on different chromosomes, and they are randomly assorted during meiosis.

Question 15

Law of Dominance

Answer 15

This law states that when two different alleles are present in an individual, one allele (the dominant allele) will be expressed, while the other allele (the recessive allele) will be masked.
These principles explain why some traits are inherited in a predictable manner, such as eye color or blood type. They also form the basis for genetic counseling and the study of genetic disorders.

Question 16

Shortcomings of Mendelian Genetics

Answer 16

• do not explain all aspects of genetic inheritance (e.g., some traits are not determined by a single gene but rather by multiple genes)
• genetic traits are influenced by environmental factors
• does not account for other forms of inheritance (e.g., mitochondrial inheritance)

Question 17

Relative risk

Answer 17

When talking about multifactorial diseases, we can only talk about the relative risk to develop a disease. Genetic predisposition expressed in terms of a relative risk.

Question 18

Explain threshold model

Answer 18

Gaussian distribution shifts (to the right) depending on your genetic constitution. As it shifts more people in that subpopulation/group will get a disorder. When a threshold is reached - you are affected - getting a disorder.

Question 19

Reccurence risk

Answer 19

Risk of getting a disease (passing the threshold). More people have the risk of surpassing that threshold, as the Gaussian distribution shift to the right. So if we all belong to one family, or if we all smoke, or if we all live in a certain area (also environmental factors), we all shift to the right in our liability to lung cancer. One could even say that the threshold is moving down.