The Increasing Demand of Prenatal Genomic Testing
May 13, 2024
Access to Genomic Testing
A powerful tool in modern medicine, genomic testing offers profound insights. For expecting parents, genomic testing can illuminate potential genetic conditions that could affect their unborn child, providing crucial information that can guide decision-making about their pregnancy and the child’s future healthcare.
The roots of genomic testing date back to the completion of the Human Genome Project in 2003, an international research effort that first mapped all the genes in the human genome. This monumental achievement laid the groundwork for the development of genomic testing technologies, which have since revolutionised the fields of genetics and prenatal care. These technologies allow clinicians and researchers to understand not only single-gene disorders but also more complex genetic interactions that contribute to health and disease.
What Value Does Genomic Testing Carry
Genomic testing during pregnancy offers critical insights into the foetal genome, enabling the identification of a variety of genetic anomalies and conditions. This testing facilitates the detection of chromosomal abnormalities, such as trisomies including Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18), as well as monosomies like Turner syndrome (monosomy X). Additionally, it can diagnose single-gene disorders, such as cystic fibrosis, sickle cell anaemia, Tay-Sachs disease, and various hemoglobinopathies, which may be inherited based on parental genotypes. Genomic assays are capable of identifying minuscule genetic mutations that may lead to significant pathological conditions, particularly those resulting from de novo mutations that appear spontaneously without a family history. These tests also accurately determine foetal sex early in gestation through the detection of Y chromosome sequences.
Beyond pathological conditions, genomic testing can also discern inherited genetic traits, including blood type and potential phenotypic characteristics. More sophisticated genomic analyses can detect microdeletions and microduplications—subtle alterations in the DNA that may be linked to specific syndromes or developmental abnormalities not detectable by conventional chromosomal testing. But is there a point of knowing too much?
The Clinician Crisis
There is a rapidly growing demand for prenatal genomic testing in Australia, highlighted by recent advancements in paediatric neurology. These advancements encompass a range of tests now covered under the Medical Benefits Schedule, sponsored by both industry and research, for identifying monogenic causes of conditions like epilepsy, neuromuscular disorders, and syndromic intellectual disabilities. Ethical and legal standards require that patients receive pre-test counselling to ensure informed consent for genomic testing.
To address this need, the field of professional genetic counselling has evolved. Genetic counsellors are highly trained professionals with a Master of Science degree covering clinical genetics and genomics, counselling, research, and health communication. They follow rigorous standards set by the National Alliance of Self-Regulating Health Professions under the Human Genetics Society of Australasia. Employing a psychotherapeutic approach, genetic counsellors assist patients and their families in making informed decisions about genetic testing and the interpretation of results. The counselling process is patient-centred, aiming to build strong rapport and enhance genetic literacy among clients.
The counselling covers a broad array of topics to tailor decisions to personal values and needs, including specific genes involved, inheritance patterns, gene penetrance, possible phenotypes, and the testing process and timeframe, including how results will be communicated. It also addresses the clinical implications for the patient and their family members regarding potential outcomes of the test, such as pathogenic results, negative results, variants of uncertain significance, and incidental findings. Discussions may also explore recurrence risks, options for future pregnancies, associated costs, insurance issues, and concerns regarding privacy and confidentiality. It is obvious that psychotherapeutic approach to prenatal genomic testing is paramount to the outcome of the delivered information.
The Ethical Landscape
Ethical dilemmas such as the decision to disclose or withhold genetic results are well-known in genomic testing. For many expectants, these dilemmas are compounded by the challenges of managing a new potentially devastating diagnosis and navigating the options of our healthcare system. Effective psychological adaptation to genetic test results is heavily dependent on thorough pre-test counselling, which should educate and foster a trust-based relationship between patients and healthcare providers, facilitating better navigation of post-test realities.
Genetic counsellors operate under the fundamental ethical principles of veracity, dignity, and accountability, which are crucial in how risks and options are communicated to patients. These professionals must delicately balance the principles of non-maleficence and beneficence, considering the multifaceted risks to the patient’s physical, emotional, social, and financial health. This approach is aligned with the Human Genetics Society of Australasia’s best practice standards, which dictate a comprehensive disclosure of all aspects of testing, including potential outcomes as part of the informed consent process.
Support At All Touchpoints
The role of clinicians in supporting families during the genomic testing process is pivotal and extends beyond the specialist genetic counsellors to encompass a broader range of healthcare professionals. These clinicians, including obstetricians, paediatricians, family physicians, and nurses, play crucial roles in the multidisciplinary team that supports families through the complexities of genomic testing.
From the initial stages, broader clinicians are often the first point of contact for expectant parents considering genomic testing. They are responsible for identifying families who might benefit from such testing based on medical history and presenting concerns. Their role involves providing initial information about the availability and implications of genomic testing, helping to set realistic expectations and preparing families for the potential outcomes.
Once a family decides to proceed with genomic testing, these clinicians collaborate closely with genetic counsellors to ensure a seamless continuum of care. They assist in the interpretation of test results, contextualising medical information to the family’s specific situation, discussing the clinical implications of test findings, potential treatment or management options, and the broader impact on family planning and future healthcare decisions. Broader clinicians offer a compassionate presence, lending an empathetic ear to fears and hopes, and providing encouragement and psychological comfort.
Moreover, clinicians play a key role in advocating for the family’s needs within the healthcare system. This includes facilitating referrals to specialist care, coordinating with multidisciplinary teams, and sometimes liaising with support organisations or patient advocacy groups. They ensure that families receive comprehensive support, addressing not just the medical but also the emotional, social, and practical needs that arise during this challenging time.
In all cases, it is imperative that such testing be preceded by comprehensive genetic counselling to discuss the potential outcomes and their implications, addressing the ethical, emotional, and medical complexities that may arise from the genomic findings.
Cormack, M. et al. (2024) Mainstreaming genomic testing: Pre‐test counselling and informed consent, The Medical Journal of Australia. Available at: https://www.mja.com.au/journal/2024/220/8/mainstreaming-genomic-testing-pre-test-counselling-and-informed-consent
McKinn, S., Javid, N., Newson, A.J., Freeman, L., Bonner, C., Shand, A.W., Nassar, N. and Bell, K.J.L. (2022), Clinician views and experiences of non-invasive prenatal genetic screening tests in Australia. Aust N Z J Obstet Gynaecol, 62: 830-837. https://doi.org/10.1111/ajo.13533
