Genetic diseases arise because of variations in our DNA. These variations can be single gene mutations, involve multiple genes (polygenic diseases), or come from big changes to our chromosomes. They can be passed down by your parents or they can occur randomly because of things like cell replication errors or environmental damage. Some well known genetic diseases are cystic fibrosis, breast cancer, diabetes, and autism.
So far, scientists have found over 7,500 genetic diseases linked to about 5,000 genes. Single gene mutations occur in about 1 in 50 people. Polygenic diseases are more difficult to diagnose. This is because polygenic genes interact to heighten susceptibility to the environment, and correspondingly, the environment influences the expression of genes through epigenetics.
What are the benefits of genetic testing?
- Provide clarity: genetic tests can confirm or rule out what’s wrong when symptoms are confusing or similar to other conditions, or predict the risk of getting polygenic diseases.
- Evoke action: positive genetic test results can point people towards preventative measures, early interventions, appropriate medical monitoring and management plans, and treatments.
- Bring certainty: positive genetic test results can help people make more informed decisions about their future, such as family planning, work arrangements, and lifestyle choices.
- Use time wisely: negative genetic test results can help people avoid unnecessary check-ups and screenings and focus on finding the real diagnosis.
What types of genetic tests are there?
Genetic tests analyse a person’s DNA to detect variations that are associated with certain diseases. Genetic tests can check genes, chromosomes, or proteins.
- Gene tests study the sequence of DNA to look for variations in one or more genes, or across all of a person’s genes.
- Chromosomal tests analyse the structure of DNA. They look for large-scale changes, like extra copies or missing chromosomes, rearrangements, or large segments added or missing.
- Biochemical tests measure the activity of proteins and can give us clues about changes in particular genes.
There are currently tens of thousands of genetic tests in use, with more being developed.
What are the limitations of genetic testing?
Genetic tests are useful if you’re experiencing unexplained symptoms and they might be genetic. Genetic tests can’t tell you when symptoms will show up, or how bad they’ll be, but they can help give you an explanation if you are experiencing symptoms.
It is important to remember:
Genetic testing can give you important information about your health and empower you to make informed decisions. But they only work for diseases with a known genetic cause. For polygenic diseases, genetic testing may not provide conclusive answers but can help you understand your level of risk.
It all comes down to the condition and its genetic components when determining the usefulness of genetic tests. That’s where we can help!
