Genetic health
Genetics is the study of genes and variations in genes. It looks at how traits and characteristics pass from one generation to the next through DNA.
Genes are like recipes
It can be helpful to think of your genetic information as a cookbook. A cookbook provides instructions for making meals with recipes. Genes are like recipes that provide instructions for your body on how to grow and develop. Genes or the ‘recipes’ are made of DNA, which are like the words in the recipes.
A cookbook usually organises recipes into chapters, which are like chromosomes. Genes are organised into ‘chapters’ called chromosomes. The complete cookbook can be thought of as a genome. The genome includes all your DNA, genes, and chromosomes.
Every person has the same cookbook but has a slightly different edition. The small changes are what makes everyone unique, and why some people might have a recipe for blue eyes, while others will have a recipe for brown eyes. Sometimes, small changes in a recipe or a word in a recipe can change how a recipe (a gene) works. The change might affect how your body grows and develops, causing a genetic condition.
Watch Talking about our genes and our health: What is DNA and what stories does it hold? to learn more about DNA.
Genetics terms
Common genetic terms are described below. A longer list of terms and definitions is available on the Genomics Australia website.
DNA
Deoxyribonucleic acid (DNA) is found in all the cells in our bodies. DNA is made up of 4 building blocks, that can be thought of as the letters that make up the words in recipes. The scientific name for these chemical building blocks is nucleotide. Nucleotides are labelled with 4 letters – A, T, G, C – which join up to make long strands.
Genes
Genes are made up of sections of DNA. The bases, or letters, in the DNA are arranged into long sequences that contain instructions for your body. Each gene provides instructions that tell your body how to grow and develop. For example, some genes determine the colour of your eyes.
Humans have approximately 20,000 genes. Everyone has two copies of each gene: one comes from their genetic mother, and the other comes from their genetic father.
The study of genes is called genetics.
Chromosomes
Chromosomes are structures inside our cells that hold all our genetic information.
Because each gene is made up of long sections of DNA and people have thousands of genes, DNA is packaged into chromosomes. DNA strands are coiled up tightly so all the genetic information can fit inside each of our cells.
Humans have 23 pairs of chromosomes (46 in total). One pair of chromosomes comes from our genetic mother and one pair from our genetic father. One of the pairs of chromosomes are sex chromosomes and determine the sex of an individual. Most females have two X chromosomes and most males have one X chromosome and one Y chromosome. Chromosomes do not determine a person’s gender. A person’s gender is self-determined and is felt and expressed individually.
Genome
Genome is the word used to describe the complete set of genetic information inside cells. It includes all the DNA and genes a person has. The study of genomes is called genomics.
Glossary of terms
For more genetics terms, you can look at the following resources.
Genetic health care
Genetic health care aims to help you understand how genes can affect health. Genetic health care is usually provided by clinical geneticists (doctors) or genetic counsellors (allied health professionals). It can be provided by many health professionals for many different reasons.
Genetic health care is for anyone with:
- a genetic condition
- a family history of illness
- concerns about inherited conditions.
Genetic health care can help by providing:
- an earlier or more accurate diagnosis
- prevention or monitoring for health conditions
- more informed health care or family planning decisions.
Genetic health care usually starts with an appointment with a health professional. Clinical geneticists (doctors) and genetic counsellors (allied health professionals) are experts in genetics. They are trained to help you understand genetics and what it means to you.
What genetic health care may include
- Genetic counselling – a conversation to help you understand genetic information and what it means for your specific circumstances.
- Genetic testing – a tool to understand genetic information associated with health conditions.
- Screening and prevention – methods to identify risks early so health can be monitored or managed.
- Personalised (precision) medicine – treatment based on your DNA. For example, choosing certain cancer medications that work best for certain cancer genes.
Find genetic health care in WA
In WA, there are many ways you can access genetic health care, including:
- your GP, who can order some genetic tests or provide a referral to a specialist service if required
- ther medical specialists, such as an oncologist
- various medical clinics
- private clinical genetic clinics (for a list of services, visit the Human Genetics Society of Australasia website.
If you have any questions or concerns about your genetic health, a good place to start is to talk to your GP.
Your genetics appointment
A genetics appointment is usually with a genetic counsellor or clinical geneticist. In the appointment, you will often talk about your medical history. You might also discuss your family’s health history. It’s helpful to bring any family health information you have, but it’s okay if this isn’t available. Examples of family health information include a condition and when someone was diagnosed.
Clinical assessment
A health professional, usually a clinical geneticist, will talk with you about your health and family history. This helps to understand your chance of having or developing a genetic condition. They will explain your options and discuss whether any further tests may be helpful.
Sometimes a physical examination is done to help with diagnosis and care planning. Support is provided to help you understand the information and any emotional impacts.
Genetic counselling
Genetic counselling provides personalised information and support for individuals or families. It is useful for people affected by, or at increased chance of having, a genetic condition.
Genetic counselling helps you understand and adapt to the medical, emotional and family impacts of genetics. It can also support informed decision-making about your health care, like whether you go ahead with genetic testing. It is not a psychological or psychiatric assessment.
Genetic counselling is usually provided by genetic counsellors and clinical geneticists.
Genetic testing
Genetic or genomic testing may be offered to help confirm or clarify a genetic condition. Testing is optional. You can choose not to have testing or take time to decide.
Before any test, you will:
- be given clear information
- have time to ask questions
- be asked to provide informed consent.
Genetics and precision medicine
Precision medicine is a way to tailor health care to individuals. It is also called personalised medicine.
Precision medicine uses your genetic information and other health information to help prevent, diagnose and treat disease. Instead of a ‘one-size-fits-all’ approach to treatment, health professionals can provide more precise and targeted health care.
An example of precision medicine is finding the right cancer treatment. Somatic genetic testing can test DNA in a tumour. The test results can provide information about how the cancer is likely to respond to different treatment options. Different people with the same type of cancer might respond differently to certain treatments.