Carrier testing in children and adolescents

Parental request for familial carrier testing in early childhood: The genetic counseling perspective

Professional guidelines generally caution against carrier testing in minors, though prior research indicates parents request and providers sometimes facilitate testing for unaffected siblings of a child affected by a genetic disorder. We investigated the perspectives of genetic counselors in North America regarding carrier testing prior to adolescence. Practicing genetic counselors (n = 177) responded to an electronic survey assessing their willingness to facilitate testing in four hypothetical scenarios and their evaluation of parental motivations. Participants did not find parental arguments for testing persuasive, and most were unwilling to facilitate carrier testing in children. A significant interaction effect indicated the presence of nonactionable carrier-associated health risks in adulthood made participants significantly less hesitant when the mode of inheritance was X-linked. Participants considered parental motivations that center the child's interests as significantly more persuasive. This study suggests genetic counselors are resistant to carrier testing for familial disorders in young children and tend to align with current guidelines, yet they recognize nuance in various cases. Further investigation into this topic is warranted to support genetic counselors facing these requests as the ethics of pediatric carrier testing continues to be debated.

Adolescents' experiences and views of the national school-based thalassaemia screening programme in Malaysia: a qualitative study

In 2016, a national school-based thalassemia screening programme was implemented in Malaysia. This study aimed to explore the experiences and views of adolescents from an urban school who had undergone the screening programme. We carried out in-depth interviews with 18 participants aged between 18 and 19 years old, with 12 of them identified as carriers during the school screening. Interviews were transcribed verbatim and analysed using thematic analysis. Three main themes emerged from this study: (1) issues encountered at various levels of the school screening programme: appropriate age for screening, thalassaemia education in school, parental consent and follow-up visit and post-test counselling; (2) experiencing emotional rollercoaster: worry, anxiety, shame, stigma; (3) choosing future partners after carrier status was known-prepared or unprepared? Various issues and screening-related challenges were encountered before, during and after the screening test. Recommendations include improving thalassaemia screening education for both school-going adolescents and parents, and better follow-up care and support for those identified as carriers. These will help stakeholders to be well informed and supportive of thalassaemia screening in schools.

Human Genetics Society of Australasia Position Statement: Genetic Carrier Testing for Recessive Conditions

This Position Statement provides guidelines to assist all health professionals who receive requests for carrier testing and laboratory staff conducting the tests.In this Statement, the term 'carrier testing' refers to genetic testing in an individual to determine whether they have inherited a pathogenic variant associated with an autosomal or X-linked recessive condition previously identified in a blood relative. Carrier testing recommendations: (1) Carrier testing should only be performed with the individual's knowledge and consent; (2) An individual considering (for themselves, or on behalf of another) whether to have a carrier test should be supported to make an informed decision; (3) The mode of inheritance, the individual's personal experience with the condition, and the healthcare setting in which the test is being performed should be considered when determining whether carrier testing should be offered by a genetic health professional. Regarding children and young people: Unless there is direct medical benefit in the immediate future, the default position should be to postpone carrier testing until the child or young person can be supported to make an informed decision. There may be some specific situations where it is appropriate to facilitate carrier testing in children and young people (see section in this article). In such cases, testing should only be offered with pre- and post-test genetic counseling in which genetic health professionals and parents/guardians should explore the rationale for testing and the interests of the child and the family.

Experiences of adolescents and their parents after receiving adolescents' genomic screening results

There has been considerable debate over whether adolescents should have the opportunity to learn genetic information about adult-onset disease risk and carrier status without a clinical indication. Adolescents face increasing opportunities to learn more about such genetic risks through the return of secondary findings from clinical genomic testing, direct-to-consumer genetic testing, and research opportunities. However, little is known about the perspectives of adolescents who have received genomic screening results. We conducted separate qualitative interviews with 15 adolescents and their parents who enrolled in a research protocol where they decided which genomic screening results to receive for the adolescent for up to 32 conditions informed by 84 genes. The goal of these interviews was to explore the impact of adolescents learning genomic results without a clinical indication for screening. Of the participating dyads, four received positive results for a pathogenic/likely pathogenic (P/LP) variant for an autosomal dominant (AD) condition, five received carrier results for a heterozygous P/LP variant for an autosomal recessive (AR) condition, and six received negative results. An interpretive descriptive qualitative approach was used. Interview transcripts were coded using a guide developed by the study team based on themes that emerged from the interviews. Degree of recall and description of results, actionability, and emotional responses differed according to the types of results received. However, all participants were satisfied with their decision to learn results, and most did not report any lasting psychological harms. Participants adapted to genomic information about themselves, even after learning about unexpected increased risk for future health problems. Our findings support the position that, whenever possible, perspectives and wishes of adolescents should be strongly considered and respected in the decision-making process regarding genetic testing.

Expanded universal carrier screening and its implementation within a publicly funded healthcare service

Carrier screening, a well-established clinical initiative, has been slow to take advantage of the new possibilities offered by high-throughput next generation sequencing technologies. There is evidence of significant benefit in expanding carrier screening to include multiple autosomal recessive conditions and offering a ‘universal’ carrier screen that could be used for a pan-ethnic population. However, the challenges of implementing such a programme and the difficulties of demonstrating efficacy worthy of public health investment are significant barriers. In order for such a programme to be successful, it would need to be applicable and acceptable to the population, which may be ethnically and culturally diverse. There are significant practical and ethical implications associated with determining which variants, genes and conditions to include whilst maintaining adequate sensitivity and accuracy. Although preconception screening would maximise the potential benefits from universal carrier screening, the resource implications of different modes of delivery need to be carefully evaluated and balanced against maximising reproductive autonomy and ensuring equity of access. Currently, although a number of existing initiatives are increasing access to carrier screening, there is insufficient evidence to inform the development of a publicly funded, expanded, universal carrier screening programme that would justify investment over other healthcare interventions.

Ethics in genetic counselling

Difficult ethical issues arise for patients and professionals in medical genetics, and often relate to the patient's family or their social context. Tackling these issues requires sensitivity to nuances of communication and a commitment to clarity and consistency. It also benefits from an awareness of different approaches to ethical theory. Many of the ethical problems encountered in genetics relate to tensions between the wishes or interests of different people, sometimes even people who do not (yet) exist or exist as embryos, either in an established pregnancy or in vitro. Concern for the long-term welfare of a child or young person, or possible future children, or for other members of the family, may lead to tensions felt by the patient (client) in genetic counselling. Differences in perspective may also arise between the patient and professional when the latter recommends disclosure of information to relatives and the patient finds that too difficult, or when the professional considers the genetic testing of a child, sought by parents, to be inappropriate. The expectations of a patient's community may also lead to the differences in perspective between patient and counsellor. Recent developments of genetic technology permit genome-wide investigations. These have generated additional and more complex data that amplify and exacerbate some pre-existing ethical problems, including those presented by incidental (additional sought and secondary) findings and the recognition of variants currently of uncertain significance, so that reports of genomic investigations may often be provisional rather than definitive. Experience is being gained with these problems but substantial challenges are likely to persist in the long term.

"They Just Want to Know" - Genetic Health Professionals' Beliefs About Why Parents Want to Know their Child's Carrier Status

In the context of a child being diagnosed with a genetic condition, reports from both parents and health professionals suggest many genetic health professionals are reluctant to provide carrier testing for unaffected siblings, despite the lack of evidence of harm. We propose that genetic health professionals' understandings of why parents want to have their children tested may contribute to their reluctance to test. We draw on interviews with 17 genetic health professionals, reporting their beliefs about parents' motivations for testing and their intentions to communicate results to their children. Data were analyzed using inductive content analysis. Genetic health professionals reported attributions that contrasted with reasons parents actually report. These disparities fall into two categories: 1) attributing reasons that parents do not themselves report (i.e. for reassurance about their child's health), and 2) not recognizing the reasons that parents actually do report for wanting testing (i.e. to communicate the information to their child). By identifying that genetic health professionals may be misattributing reasons to parents for desiring their child"s carrier status, they may be missing an opportunity to assist parents to make decisions that are in line with their values and the best interests of the family.