Causes of Disease Flashcards
What does Etiology mean?
- The study of the cause of disease.
- Diseases can have a single cause or be the product of multiple factors.
What does Idiopathic mean?
Conditions with no KNOWN causes
What are diseases usually classified as?
Intrinsic - From within
Extrinsic - From outside
List the Intrinsic causes of disease
Changes in an individual’s genome
- Nuclear or Mitochondrial
- Inherited mutations and other genetic variations
- de novo mutations
- Epigenetic modifications
How can changes in genes causes disease
Alter the function of a gene or a group of genes.
- More/less proteins or same amount but more/less activity of proteins
How can genetic variations manifest at a variety of levels
Cell Autonomously - Mutation affects the cell itself.
Cell X no longer expresses structural protein Y, so cell X is the wrong shape
Cell non-autonomously - Mutation affects other cells but not itself.
Cell X no longer secretes protein hormone Y, so cell Z no longer functions
List the extrinsic causes of disease
- Injury
- Infection
- Nutrition and diet
- Lifestyle, e.g. smoking, exposure to workplace toxins
- Chemical poisoning (acute and chronic)
- Exposure to radiation
- Physcosocial Stress
When can the classifications be ambiguous
Causes of disease are often a chain of events.
Are allergies caused by a sensitive immune system (intrinsic) or the preceding allergen (extrinsic)?
Intrinsic or extrinsic depends on viewpoint. Extrinsic to what: cell, tissue, organ, body
Explain multiple causes of disease
Many diseases are the product of multiple interacting factors.
“Risk factor” can be a more accurate term than cause.
Other “diseases” are umbrella terms for a variety of conditions with different causes, but similar signs/symptoms/ pathologies
Explain how age can be a cause for disease
Age is a contributing factor to many diseases, but is it a cause?
Age often just means ‘time’, in the context of causes that accumulate.
Give examples where age can be a cause of disease
Age can be an intrinsic cause when it describes the biological ageing process.
E.g.: Ageing => Menopause => decreased oestrogen => risk of osteoporosis.
Many diseases associated with chronic inflammation also have a biological ageing as a cause.
What are the alternative descriptions for disease classification
Genetic and Environmental
Parkinson’s disease risk factors are:
- Age
- Genetics
- Environment
What are some Intrinsic diseases
- Cancer (inc. Leukaemia, Lymphoma, Myeloma, Breast, Prostate)
- Developmental diseases(e.g. Neural tube defects)
- Inherited anaemia(e.g. Sickle cell disease, β-thalassaemia)
- Inherited metabolic diseases(e.g. phenylketonuria)
What is the cause of Down syndrome
Trisomy of chromosome 21, inherited at conception
Intrinsic
What is the cause of COVID-19
Infection with SARS-CoV-2
Extrinsic
