Genetic testing is one of the most rapidly evolving areas of modern medicine, but it is also often overlooked. In this episode of the Her Health™ Podcast, Frieda Loubser, a genetic counsellor with over two decades in the field, brought rare clarity to a space that generates as much anxiety as it does answers.
From cancer genetics and the BRCA gene to carrier screening, newborn testing, and the real limitations of direct-to-consumer genetic tests, Frieda simplified what genetic testing actually tells us – and where the science still has a long way to go.
Rapid Fire: What Matters in Genetic Health, Rated
We asked Frieda to rate common factors from zero to 10 based on their importance:
- Cancer screening – 10/10: Non-negotiable.
- Knowing your family history – 10/10: One of the most powerful tools available.
- Newborn screening – 10/10: Early detection before symptoms appear is crucial.
- Carrier screening – 9/10: Highly effective when done at the right time – ideally before pregnancy.
- Embryo testing – 10/10 context-specific: For families facing serious genetic conditions, it changes everything.
- Testing your genes for longevity – 0/10: The science simply isn’t there yet.
- Testing your exercise potential – 2/10.
- Testing your weight loss and dietary genetics – 3/10: More on why below.
- Living a healthy life and eating properly – 10/10: The foundation that no genetic test can replace.
Genetics – What It Actually Is
Frieda opened with an analogy that made the abstract immediately tangible. She described the body as a factory – thousands of functions happening simultaneously to build and maintain every system. Each gene is like a Lego booklet: a set of instructions for building a specific factory worker, one block at a time.
We have 20,000 of these booklets. One copy from each parent, for most genes. When the instructions are correct, everything is built as it should be. When there is a spelling error – a mutation – the effect depends on where in the booklet the error appears and whether the other copy can compensate.
She explained that in recessive conditions, one working copy is often enough. The backup covers the gap. In dominant conditions, a single faulty copy causes a problem by itself – as in achondroplasia, a form of dwarfism, where one change in the gene causes the shortening of the long bones regardless of what the other copy says.
“If there’s a spelling error on page one that introduces a stop instruction – you’re not building anything at all. If the error is on page 50, that traffic officer can’t do its job.”
Family History – Still the Most Powerful Tool
Frieda was emphatic that family history remains one of the most valuable and underutilised tools in genetic risk assessment. It suggests which genes to look for and provides essential context for interpreting results.
She addressed a common misconception directly: cancer risk can be inherited from the father’s side just as easily as the mother’s. A gene like BRCA1 is inherited from both parents. A spelling error can come from either side – and if the risk is travelling through men in a family, it might never be apparent from the family history because men have a significantly lower risk of developing breast cancer themselves.
She recommended looking at three generations: your own, your parents’, and your grandparents’ – including their siblings where possible. The structure of the family matters as much as the diagnoses within it.
The BRCA Gene – What a Negative Result Actually Means
Frieda addressed this through a real example from the conversation: a family with four generations of breast cancer, and a mother who has tested negative for BRCA1 and BRCA2.
She explained that breast cancer falls into three broad groups. Around 70% is sporadic – age-related, occurring without a strong genetic driver. Around 10% is linked to moderate or high-risk predisposing genes like BRCA1 and BRCA2. But between those two groups sits a third – families with multiple lower-risk genetic factors that accumulate over generations, for which testing doesn’t yet exist in a reliable or comprehensive form.
“We know some families don’t have one high-risk gene, but could potentially have multiple low-risk genetic factors that are accumulating.”
A negative BRCA result doesn’t mean no genetic risk. It means no identified high-risk variant in the genes tested. Research into polygenic risk scores – algorithms that account for the combined effect of many small genetic factors – is advancing rapidly, but isn’t yet at a point where it can be used clinically with confidence.
The practical implication: a significant family history of breast cancer still warrants careful monitoring and specialist involvement, regardless of a negative genetic test result.
Carrier Screening – Before the Pregnancy, Not During It
Carrier screening was one of Frieda’s clearest recommendations for couples planning a pregnancy. She explained that everyone carries variants in some of their 20,000 genes – but only around 1% of couples are carriers in the same gene. When that overlap occurs, there is a one in four chance with each pregnancy that the baby might be affected.
The critical point was that family history doesn’t flag this risk. Carrying one working copy of a gene is completely protective – it causes no symptoms and leaves no trace in the family picture. The risk only becomes visible when both partners happen to carry a variant in the same gene.
Carrier screening is most powerful when done before conception – when it creates options: testing embryos before transfer, testing the pregnancy, or making informed decisions about donors. Done during pregnancy, it provides information but fewer choices.
Newborn Screening – Why Timing Is Everything
Newborn screening is different from genetic testing. It is a biochemical test – a heel prick at around day three of life – checking whether specific enzymes are present and functioning. It screens for over 20 severe metabolic conditions where early detection, before symptoms appear, can prevent irreversible damage.
Frieda explained the mechanism: some conditions cause a specific molecule to build up in the body when the enzyme responsible for breaking it down is absent. That buildup, if it reaches the brain, can cause permanent damage. A simple dietary change – removing the problematic molecule from formula – can prevent that entirely if the condition is caught early enough.
She was candid that the timing and delivery of the information are often poorly handled. Day three of a newborn’s life is not the ideal moment to be making informed decisions about genetic screening. Her advice was to gather the information beforehand – to know what the test covers and why, before the moment of decision arrives.
Embryo Testing – Adding to the Options
Pre-implantation genetic testing (PGT-M) is a technology Frieda described as expanding choices rather than making decisions. It involves IVF – not necessarily because of a fertility problem, but to allow embryos to be tested in the laboratory before being transferred to the uterus.
Five to ten cells are biopsied from the outer layer of a five-day embryo – the cells that will become the placenta, not the foetus – and tested. Affected and unaffected embryos can then be identified before a pregnancy begins. For couples facing a high risk of passing on a serious, life-threatening condition, it offers a way to start a pregnancy with certainty that the baby won’t be affected.
Frieda acknowledged that people bring different ethical, religious, and personal frameworks to this decision – and that the goal of genetic counselling is always to support informed decision-making, not to direct it.
One Takeaway Everyone Should Know
“Family history remains really important in terms of giving us a clue of which genes to test for – but also when you have your genetic results, we would then interpret them in the context of the family history.”
Genetics is advancing faster than almost any other field in medicine – and as Dr Frieda Loubser reminded us on this episode, the most powerful thing most people can do right now isn’t to order a genetic test. It is to have the conversations in their own families that turn vague impressions of health history into a picture a specialist can actually use.
🎧 Interested to hear more about cancer risk and screening protocols? Listen to the episode with radiologist Dr Tamiya Nair – Know Your Risk: Cancer Screening & Early Detection – here.
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This content is for informational purposes only and does not constitute medical advice. Always consult with your healthcare provider or a qualified genetic counsellor before making any decisions based on genetic testing or family history. This unregistered medicine has not been evaluated by SAHPRA for its quality, safety or intended use. If symptoms persist, consult your healthcare provider.
