Event Review: BSGM Lunch and Learn – Preconception carrier screening

Preconception carrier screening (PCS) – the subject of a recent British Society for Genetic Medicine (BSGM) 'Lunch and Learn' event – is a genetic test typically offered to couples planning a pregnancy. The purpose of PCS is to identify couples who are carriers of alleles for autosomal recessive conditions. If both parents are carriers then they are more likely to have a child with a genetic condition, such as spinal muscular atrophy. The test is performed prior to pregnancy, in order to help the couple make informed reproductive choices.

PCS can be controversial topic, because while it offers prospective parents an opportunity to make informed decisions about passing on potentially lethal mutations, it also raises concerns about the stigmatisation of certain genetic traits. Ethical studies have considered whether carriers' self-esteem will be affected, or whether certain births will be avoided due to negative stereotypes associated with genetic traits.

The event featured two talks by clinical experts on PCS, followed by an opportunity for questions.

Professor Yuval Yaron, head of the Prenatal Genetic Diagnosis Unit at Tel Aviv Medical Centre, Israel, described the PCS tests offered to Israeli citizens and residents with blue IDs. He detailed the history of this programme from the 1980s to 2024, when an expanded screening programme was launched to accommodate more conditions and greater diversity within the population.

Of the two talks, I found Professor Yaron's more accessible to a lay audience, and enjoyed the discussion of the logistical considerations involved in setting up a large-scale programme of this type. These considerations included how the benefits of different genetic profiling technology are weighed, and how screening is offered to a prospective mother first to determine whether further screening will be recommended for the prospective father.

The talk also addressed Professor Yaron's work on new digital tools, such as a digital genetic assistant, that can aid clinicians in providing screening for a large population. Some research indicates that information that is not directly communicated by clinicians can leave some patients feeling as though they are not sufficiently knowledgeable about genetic conditions and prenatal screening. I question whether a digital genetic assistant can help with this issue, but I was glad to see that patient comprehension assessments were used to test the efficacy of these tools.

Professor Martin Delatycki, a clinical geneticist and co-director of the Bruce Lefroy Centre at the Murdoch Children's Research Institute, Melbourne, Australia, followed. His talk, I felt, was more suited to people with a genetics background. Initially he focused on the complicated genetic inheritance of Fragile X syndrome (FXS). This is a condition associated with intellectual disability of varying severity, higher incidences of autism, and – in some cases – connective tissue dysplasia. It is caused by mutations within the FMR1 gene, which lead to large repeat sequences within the gene.

Professor Delatycki explained how interruptions to the repeat sequences can prevent the development of FXS. He linked this to PCS, explaining the importance of screening for such interruptions, and reflected on how clinicians should communicate low levels of inheritance risk to parents. While this was scientifically interesting, I found it slightly odd to place such emphasis on screening for a condition where those affected generally have a normal life expectancy.

The second half of Professor Delatycki's talk discussed his work on Mackenzie's Mission, a research initiative inspired by Mackenzie Casella, who died at seven months of age due to a severe case of spinal muscular atrophy. At the time of her birth, her parents were not aware that they were carriers. Subsequently, they lobbied the federal government in Australia to investigate the merits of a national PCS programme, leading to the initiative.

Professor Delatycki discussed how the variants screened for during PCS were selected, although he did not list the relevant conditions. He also explained that the aim was to recruit participants who were truly representative of the Australian population, as reflected in 2021 census data. It was a shame, then, to see that the actual participant pool was predominantly made up of graduates of European descent.

The study additionally analysed couples' reactions to the screening results, such as whether they chose to avoid having a child with a particular condition. While this is an important avenue of investigation, it was odd to see couples' complex decisions presented through such a strictly clinical lens. At the end of his talk, Professor Delatycki detailed a follow-up study concerning screening for genes that can lead to deafness in later life.

Unfortunately, I feel that the question-and-answer session that followed was a missed opportunity for thought-provoking debate among experts. There was no follow-up on questions, and so the nuance of answers was missed. Due to the mentions of FXS and deafness, I was curious about the researchers' thoughts on policy procedures surrounding disability, and the implications of their work from a less clinical angle. I believe that I was not the only attendee with this on my mind.

To this end, I asked whether the speakers had any comments on the intersection between carrier screening and disability rights, either globally or within the regions where they practice. I was disappointed to receive a politician's answer. Both researchers agreed that screening programmes should be constantly re-evaluated, but they suggested that PCS is no different to screening for Down's syndrome, which is something offered in many countries.

I think an argument can be made that there is an important distinction between screening for potentially fatal recessive disorders, and screening for conditions where most people affected live long and fulfilling lives. The speakers' views on the matter were valid, as far as they went, but I hoped that experts would have more to share.

Overall, the event was informative and engaging, yet I think it failed to address some important social aspects of this subject, leaving ethical considerations largely to the audience. I can understand why speakers might be hesitant to delve deeply into discussions of disability and ethics at a relatively brief event, but I would be keen to see this area given more detailed attention at a future event in this series.