Epigenetics & Disease
Biology: AQA A Level, topic 8.2.7
Causing Disease
Epigenetics can cause disease if they are not controlled properly.
Abnormal methylation
- Epigenetic changes can cause diseases (e.g. cancer).
- Methyl groups are epigenetic markers that bind to DNA to inhibit transcription.
- Methyl groups are important in regulating processes like cell division.
- If methylation is not regulated properly, this can affect the regulation of these important processes. This is called abnormal methylation.
Increased methylation
- If methylation is increased too much, it can decrease the gene expression of tumour suppressor genes more than normal.
- Tumour suppressor genes prevent cell division from taking place.
- If the genes are underexpressed, the cells divide uncontrollably and tumours are produced.
Decreased methylation
- If methylation is decreased too much, it can increase the gene expression of proto-oncogenes more than normal.
- Proto-oncogenes promote cell division.
- If the genes are overexpressed, the cells divide uncontrollably and tumours are produced.
Treating Disease
Epigenetics can also be used to treat disease because epigenetic markers can easily be removed.
Epigenetic change
- Epigenetic changes that cause disease (e.g methylation leading to cancer) are temporary and can be reversed.
- E.g. The action of the methyl transferase enzyme can be inhibited. Methyl transferase adds methyl groups (a type of epigenetic marker) to DNA to alter gene expression. If methylation is the cause of disease, inhibiting the enzyme can help treat the disease.
Drugs and therapies
- The ability to reverse epigenetic change is important for designing new drugs and therapies.
- Researchers are investigating how drugs can reverse the silencing or overexpression of genes.
- Drugs that can reverse epigenetics can help return gene expression to its normal level.
Future of epigenetics
- The understanding of epigenetics is increasing.
- It is now understood that epigenetic change could play a role in conditions like allergies and autism.
- In the future, using drugs that reverse epigenetic change could be used to treat many different conditions.
Test yourself on Epigenetics & Disease
What is the effect of increased methylation on tumour suppressor genes?
Which of the following statements about abnormal methylation are true?
Which of the following statements about treating disease are true?
How do drugs and therapies return abnormal gene expression to its normal level?