The Importance of Carrier Screening for Determining Genetic Compatibility and Reducing the Risk of Genetic Diseases

Discover how preconception carrier screening can help you make informed decisions about your fertility and your future baby’s health by minimising the risk of passing on a genetic condition. Learn about the benefits, clinical applications, and its impact on assisted reproduction.

What is Carrier Screening and Why is it Important?

Carrier screening has become an essential preconception tool for couples who want to assess the risk of passing recessive genetic diseases to their offspring. Approximately 1 in 100 people suffer from a genetic condition. Despite the common belief that these diseases only affect families with a history of genetic disorders, recent studies show that around 56.3% of couples have at least one partner carrying genes linked to recessive diseases (Abulí et al., 2016).

If both partners carry a mutation in the same gene:

• There is a 25% chance that their child will inherit the disease.
• A 50% chance that the child will be a healthy carrier.
• A 25% chance that the child will be completely free of the mutation (non-carrier).

Therefore, carrier screening provides crucial insight into the risk of passing on genetic diseases.

Types of Genetic Diseases

It is important to note that carriers typically do not experience symptoms of the disease but can pass the mutated gene to their children. Carrier screening analyses the DNA of both partners to detect the presence of genes associated with severe recessive diseases (where two copies of the mutated gene are needed for the disease to manifest) or X-linked conditions (where women can be carriers and men may be affected).

Following the recommendations of leading scientific societies such as the American College of Medical Genetics and Genomics, our Carrier Screening Test focuses on detecting serious genetic conditions that significantly impact quality of life.

The test prioritises conditions that:

• Pose a high risk of intellectual disability.
• Reduce life expectancy.
• Can be better managed with early diagnosis (including those screened for in neonatal testing).

On the other hand, the test excludes conditions such as:

• Late-onset inherited diseases (e.g. Huntington’s disease).
• Phenotypic traits with no clinical relevance (e.g. colour blindness).
• Complex diseases with low penetrance or variable expressivity (e.g. Type I Haemochromatosis).

Next-Generation Sequencing (NGS)

Next-generation sequencing (NGS) technology allows for the rapid and precise analysis of a large number of genes. This has enabled expanded carrier screening, which can analyse over 300 genes associated with 368 diseases, with a detection sensitivity of over 99% for genetic variants.

Additionally, implementing NGS in gamete donation programmes has identified that 3% of donations carry a high reproductive risk, leading to better donor selection and genetic compatibility matching.

Carrier Screening: Benefits of Genetic Testing in Reproductive Planning

The goal of this test is to provide crucial information for informed family planning and the prevention of severe genetic diseases.

Key Benefits:

✔ Understanding and reducing genetic risk – Identifies whether one or both partners carry recessive genetic mutations. In at-risk couples, Preimplantation Genetic Testing for Monogenic Disorders (PGT-M) can be used in assisted reproduction treatments to select healthy embryos, reducing the likelihood of genetic diseases.

✔ Personalised reproductive options – Couples can explore alternative options such as gamete donation or adoption, based on their test results.

✔ Gamete donation compatibility – Screening egg and sperm donors ensures that gametes used in fertility treatments are genetically compatible with the recipient couple (genetic matching), further reducing the risk of passing on genetic diseases.

✔ Greater peace of mind and preparation – For couples who choose to conceive naturally, carrier screening allows them to be aware of potential risks and prepare for any necessary medical care for their baby.

Conclusion

Carrier screening represents a significant advancement in reproductive planning, enabling couples to make informed decisions about their fertility and the health of their future children.

Its application in assisted reproduction not only improves treatment success rates but also provides reassurance to those looking to start a family—whether using their own gametes or assisted reproductive technologies.

Given its positive impact and increasing accessibility, all couples of reproductive age are encouraged to consider carrier screening as part of their family planning. Consulting a fertility specialist can be the first step in understanding more about this valuable tool and its benefits.