Causes of disease overview

Question 1

What do intrinsic (within) causes of disease relate to?

Give examples.

Answer 1

Relates to changes in an individual’s genome. All typically alter function of gene/genes.

• can be nuclear or mitochondrial genome
• inherited mutations and other genetic variations
• de novo mutations
• epigenetic modifications e.g chemical methylation, phosphorylation, acetylation of histones (anything that doesn’t change DNA sequence but changes behaviour of DNA)

Question 2

What are some extrinsic (outside) causes of disease?

Answer 2

• Injury
• Infection
• Nutrition and diet
• Lifestyle e.g smoking, exposure to workplace, toxins
• Chemical poisoning (acute and chronic)
• Exposure to radiation

Question 3

Is age a cause of diseases?

Is it intrinsic or extrinsic?

Answer 3

Age is a synonym for time. Not a cause but a factor that allows mutations to accumulate.

Can be intrinsic when it describes the biological process of ageing e.g risk of oestroporosis in women with ageing due to menopause.

Question 4

What else are diseases grouped as?

Answer 4

Genetic (intrinsic) and environmental (extrinsic), more reflective of disease.

Question 5

Is the cause of down syndrome intrinsic or extrinsic?

Answer 5

Trisomy of chromosome 21, inherited at conception. Intrinsic.

Question 6

Is COVID-19 extrinsic or intrinsic?

Answer 6

Infection with SARS-Cov2 so extrinsic

Question 7

Is cause of lung cancer extrinsic or intrinsic?

Answer 7

Multiple causes and contributing factors e.g smoking, air pollution, chemicals, family history of lung cancer.

Involves extrinsic and intrinsic causes