Genes are specific segments of DNA that give our bodies the instructions for making the proteins our bodies are made of – everything from your muscles and bones to your skin and blood cells.
Genetics is the study of genes and their roles in inheritance – in other words, the way that certain traits or conditions are passed down in the genes from one generation to the next.
The genome is what makes us ‘us.’ It is found in every cell of the body and contains all the information that the body needs to build it, and to keep it healthy. It is written in a code called DNA which is a long sequence of chemical building blocks. Each building block is known by a particular letter. Each person’s genome contains around 20,000 genes.
Everyone’s genome is slightly different. These differences are called ‘variants.’ Most variants are harmless and have no impact on our health, but some variants may cause health conditions.
Genomics is the study of an organism’s genome. and how that information is applied. All living things, from single-celled bacteria, to multi-cellular plants, animals and humans, have a genome – and it is made up of DNA.
The words ‘genetics’ and ‘genomics’ are often used interchangeably.
Genetics is the study of genes, or a particular part of the genome, whereas genomics is the study of all the DNA needed to build an organism, including the genes.
A patient may have a genomic test, but if a variant is found in a single gene it could equally be called a genetic result.
One of the most exciting developments in genomics has been the development of a technology called ‘whole genome sequencing (WGS)’ that allows us to ‘read’ a person’s whole genome relatively easily.
You may be offered a genetic test because:
- Your healthcare professional thinks you might have a health condition caused by a change in one or more of your genes
- Someone in your family has a health condition that’s caused by a change in a particular gene
- Some of your close relatives have had a particular type of cancer that could be inherited
- You or your partner have a health condition that could be passed onto your children
You should consult your doctor with any questions about having a genomic test as you will need a referral by a specialist. Patients are not able to self-refer for genomic testing.
The National Genomic Test Directory specifies which genomic tests are commissioned by the NHS in England, the technology by which they are available, and the patients who are eligible to access a test. The National Genomic Test Directory is for rare and inherited disorders and cancer. For more information visit www.england.nhs.uk/publication/national-genomic-test-directories
All National Genomic Test Directory tests are available to North Thames patients who meet the clinical eligibility criteria.
The turn-around-times for genetic and genomic tests vary based on their complexity and the clinical urgency. Some urgent test results will be available within a few days, for example, some prenatal tests, while others will be available in a few months, or even a year.
A genomic test can:
- Help to diagnose a rare health condition in an individual
- Help you understand whether an inherited health condition may affect you, your child, or another family member, and help guide reproductive decisions
- Show if you are at higher chance of developing certain health conditions, including some types of cancer
- Guide healthcare professionals in deciding what treatment to give you
- Guide healthcare professionals on whether you are able to access a clinical trial
When your result is available, your healthcare professional will explain it to you.
There are several possible outcomes of a genomic test; these depend on what kind of test is done.
- The result may show a definite cause for the health condition in your family. The result may not show a cause for the health condition in your family
- The result may be uncertain. Occasionally, further testing may be needed
- Rarely, the result may show an unexpected finding that is relevant to your health
If the testing does not find the cause of your health condition, this doesn’t mean that your condition does not have a genetic cause, as we do not yet understand everything there is to know about the genome.
It’s possible that further testing will be available in the future as we learn more.
Only healthcare professionals and clinical scientists involved in your care can access your test results
You can discuss your results with your specialist healthcare professional who arranged the test You may also be referred to a genetic counsellor or clinical geneticist to discuss your test results.
The NHS genomic laboratory will store your sample securely. This means that if, in future, your healthcare professional recommends further testing, the laboratory will already have the DNA they need.
NHS laboratories may use your samples and data to help develop tests or as controls for testing other patients.
Research is a vital component of healthcare and it has benefited from the health data donated by millions of NHS patients. All the medicines and treatments that patients receive today were developed because of patient data.
As part of the Genomic Medicine Service, many patients will be given a choice about allowing approved researchers access to their genomic data with any personalised details removed and any excess samples. A patient’s ability to access a genomic test does not depend on their willingness to consent to the use of data for research purposes, but by contributing to research you will be helping to develop the service and improve care for patients.
The National Genomic Research Library (NGRL) is a national research database owned by Genomics England which securely holds the genomic, health and sample data of patients who have undergone whole genome sequencing (WGS). All rare disease and cancer patients who are offered WGS have the opportunity to share their anonymised data with this library.
Only approved researchers can access this data, and the process of approval is rigorous.
This anonymised data is vital for advancing research, helping us to improve our understanding of human disease and develop treatments that can benefit patients with many conditions. More information about the NGRL can be found on the Genomics England website.
Your NHS test data and results are stored in a secure database for the NHS Genomic Medicine Service. Only NHS staff involved in your healthcare will know the data that relates to you.
Your data be only available to researchers outside the NHS if you have specifically agreed to this.
Your data will never be shared with insurance companies.
Taking part in research projects or having genetic tests won’t affect insurance policies you already have.
However, when applying for new insurance, you do have to disclose any symptoms you experience or any diagnoses, screening, or treatments you receive, if this information is requested on the application form.
It is important that you answer all questions truthfully when applying for insurance. If you deliberately, recklessly or carelessly give incorrect or incomplete information when answering questions, there is a risk that the insurer will decline any future claim.
As the cost of genomic testing falls and ways to speed up the analysis and the evidence for its use in other situations improves, it is likely that testing will be available for more conditions and therefore more people.
Further information is available here:
- NHS England Whole Genome Sequencing patient information leaflets https://www.england.nhs.uk/publication/whole-genome-sequencing-patient-information-leaflets/
- Genomics Education Programme Whole Genome Sequencing https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/whole-genome-sequencing/
The Genomic Medicine Service covers England only. The devolved nations are responsible for the structure and delivery of healthcare for their populations.
Genomics England is a company wholly owned by the Department of Health & Social Care. Genomics England was set up to deliver the 100,000 Genomes Project.
In the Genomic Medicine Service, Genomics England works in partnership with NHS England to ensure Whole Genome Sequencing is available to NHS patients in England.
Your relatives will not have access to your genomic record unless you are willing to share this with them.
However, the results of genomic testing may have important health implications for family members. Patients agreeing to WGS are also asked to agree to share pertinent information with relatives if needed.
Your healthcare team will support you in sharing only the information that is relevant for your relatives’ health.