A protocol for whole-exome sequencing in newborns with congenital deafness: a prospective population-based cohort

Prospective cohort study of genomic newborn screening: BabyScreen+ pilot study protocol

INTRODUCTION

Newborn bloodspot screening (NBS) is a highly successful public health programme that uses biochemical and other assays to screen for severe but treatable childhood-onset conditions. Introducing genomic sequencing into NBS programmes increases the range of detectable conditions but raises practical and ethical issues. Evidence from prospectively ascertained cohorts is required to guide policy and future implementation. This study aims to develop, implement and evaluate a genomic NBS (gNBS) pilot programme.

METHODS AND ANALYSIS

The BabyScreen+ study will pilot gNBS in three phases. In the preimplementation phase, study materials, including education resources, decision support and data collection tools, will be designed. Focus groups and key informant interviews will also be undertaken to inform delivery of the study and future gNBS programmes. During the implementation phase, we will prospectively recruit birth parents in Victoria, Australia, to screen 1000 newborns for over 600 severe, treatable, childhood-onset conditions. Clinically accredited whole genome sequencing will be performed following standard NBS using the same sample. High chance results will be returned by genetic healthcare professionals, with follow-on genetic and other confirmatory testing and referral to specialist services as required. The postimplementation phase will evaluate the feasibility of gNBS as the primary aim, and assess ethical, implementation, psychosocial and health economic factors to inform future service delivery.

ETHICS AND DISSEMINATION

This project received ethics approval from the Royal Children's Hospital Melbourne Research Ethics Committee: HREC/91500/RCHM-2023, HREC/90929/RCHM-2022 and HREC/91392/RCHM-2022. Findings will be disseminated to policy-makers, and through peer-reviewed journals and conferences.

Offering and Returning Secondary Findings in the Context of Exome Sequencing for Hearing Loss: Clinicians' Views and Experiences

BACKGROUND

There is ongoing debate regarding whether and under which circumstances secondary findings (SF) should be offered in the pediatric context. Although studies have examined patient perspectives on receiving SF, little research has been conducted examining the experiences of clinicians offering SF to parents of newborns receiving genomic sequencing for a recently diagnosed medical condition.

METHODS

To address this, we conducted qualitative interviews exploring the views and experiences of 12 clinicians who offered SF to parents of infants who had diagnostic exome sequencing (ES) to identify the cause of their hearing loss. Interviews explored clinicians' accounts of parents' choices and decision-making about receiving SF, their views on whether and when to offer SF, their experiences returning SF, and any ethical challenges they encountered. Interviews were audio-recorded, transcribed and analyzed using inductive content analysis.

RESULTS

Clinicians reported parents who declined all SF often felt finding out about future conditions unrelated to their child's hearing loss may be unhelpful, or even harmful, or were overwhelmed by their child's diagnosis. Clinicians also reported that some parents chose SF because they felt obliged to, even if they did not want to receive them. They explained that while some parents experienced decision-making regarding SF as positive, for others, this process was challenging or distressing. While clinicians generally agreed SF should be offered, mainly to promote parental choice, most felt SF should be offered after disclosing diagnostic results, primarily to avoid overwhelming parents. Clinicians encountered several ethical challenges, including balancing parental autonomy with non-maleficence, wanting to report or not report certain SF, and questioning whether parents can make an autonomous choice regarding SF.

CONCLUSIONS

Our findings, which are novel as they relate to parents of young infants with a recent diagnosis of hearing loss, add new insights into clinicians' and parents' decision-making regarding SF in pediatrics.

Analysis of Serum Inflammatory Markers in Infants Under 6 Months of Age with Non-Syndromic Moderate and Severe Hearing Loss Associated with GJB2 Gene Mutations

BACKGROUND The GJB2 gene is reported to be the main hereditary factor responsible for non-syndromic hearing impairment in infants. Several kinds of hearing loss have been linked to elevated inflammatory markers. This study aimed to evaluate serum levels of IL-2, IL-4, IL-6, IL-10, IL-17, alpha-TNF, and γ-IFN and the severity of hearing loss. MATERIAL AND METHODS Ninety newborns were divided into 3 groups: severe hearing impairment (31 infants), moderate hearing impairment (30 infants), and normal hearing (29 infants). Hearing screening was performed using otoacoustic emissions test. Mutations of the GJB2 gene were detected with Sanger sequencing. The patients had DNFB1 mutation. Seven blood inflammatory markers were tested using Cytometric Bead Array. We performed the t test to examine differences in expression of 7 inflammatory markers between sexes in the groups. The correlation between indicators within groups was studied using the Pearson correlation test. Correlation of different indicators among groups was studied using the Spearman correlation test. RESULTS When compared among the 3 groups (severe, moderate hearing impairment, and normal hearing group), we found that IL-10 had a positive correlation with the severity of GJB2-associated hearing loss, which was statistically significant (P<0.05). CONCLUSIONS This research aimed to assess the relationship of 7 serum inflammatory markers with GJB2-associated hearing loss in infants. Inflammatory marker IL-10 had a positive correlation with the severity of GJB2-associated infant hearing loss, and it might have the potential to become a future therapeutic target.

A framework for reporting secondary and incidental findings in prenatal sequencing: When and for whom?

As the use of genomic sequencing (GS) in the prenatal setting becomes more widespread, laboratories and clinicians will be tasked with making decisions about whether to offer incidental and secondary findings to expectant parents and, if so, which ones. Unfortunately, few guidelines or position statements issued by professional bodies address the return of secondary findings specifically in the context of prenatal GS, nor do they offer clear guidance on whether, and which types of incidental findings should be reported. Laboratories and clinicians will also need to navigate other challenges, such as how to obtain sufficiently informed consent, workload burdens for both laboratories and clinicians, and funding. Here we discuss these, and other challenges associated with offering incidental and secondary findings in the context of prenatal GS. We outline existing guidelines for return of these findings, prenatally and in children. We review the existing literature on stakeholder perspectives on return of incidental and secondary findings and discuss the main practical and ethical challenges that require consideration. We then propose a framework to help guide decision-making, suggesting a baseline routine analysis, with additional layers of analysis that could be offered, according to local laboratory policy, with additional opt-in consent from the parents.

Clinicians' Views and Experiences with Offering and Returning Results from Exome Sequencing to Parents of Infants with Hearing Loss

Exome sequencing (ES) is an effective method for identifying the genetic cause of hearing loss in infants diagnosed through newborn hearing screening programs. ES has the potential to be integrated into routine clinical care, yet little is known about the experiences of clinicians offering this test to families. To address this gap, clinicians involved in a clinical study using ES to identify the cause of infants' hearing loss were interviewed to explore their experiences with offering and returning results to parents. Interview transcripts were analysed using inductive content analysis. Twelve clinicians participated: seven genetic counsellors, four clinical geneticists, and one paediatrician. Most clinicians were supportive of offering ES to infants with hearing loss, primarily because results may inform the child's clinical management. However, some expressed concerns, questioning the utility of this information, particularly for isolated hearing loss. Clinicians had differing views regarding the optimal time to offer ES to families; while some felt that families can manage everything at once, others recommended delaying testing until parents have come to terms with their child's diagnosis. These findings show the complexity involved in determining how ES should be offered to families following the diagnosis of a child with hearing loss, particularly with regards to when testing is suggested.

Prenatal Diagnosis by Array Comparative Genomic Hybridization in Fetuses with Cardiac Abnormalities

Congenital heart defects (CHDs) appear in 8–10 out of 1000 live born newborns and are one of the most common causes of deaths. In fetuses, the congenital heart defects are found even 3–5 times more often. Currently, microarray comparative genomic hybridization (array CGH) is recommended by worldwide scientific organizations as a first-line test in the prenatal diagnosis of fetuses with sonographic abnormalities, especially cardiac defects. We present the results of the application of array CGH in 484 cases with prenatally diagnosed congenital heart diseases by fetal ultrasound scanning (256 isolated CHD and 228 CHD coexisting with other malformations). We identified pathogenic aberrations and likely pathogenic genetic loci for CHD in 165 fetuses and 9 copy number variants (CNVs) of unknown clinical significance. Prenatal array-CGH is a useful method allowing the identification of all unbalanced aberrations (number and structure) with a much higher resolution than the currently applied traditional assessment techniques karyotype. Due to this ability, we identified the etiology of heart defects in 37% of cases.

Genetics of Childhood Hearing Loss

Compelling evidence indicates that some newborns harboring genetic variants associated with hearing loss might not be identified by current physiologic newborn hearing screening (NBHS) rendering current NBHS protocols suboptimal. Incorporating genomic sequencing into NBHS would improve clinical diagnosis and decrease time to early intervention efforts.

New-born Hearing Screening Programmes in 2020: CODEPEH Recommendations

Programmes for early detection of congenital hearing loss have been successfully implemented mainly in developed countries, after overcoming some conceptual errors argued against their implementation and some criticism of their efficacy. However, some difficulties and weaknesses are still identified in these programmes: the detection of late-onset hearing loss and the percentage of children who did not pass the screening and did not complete the process of diagnosis and treatment, these being cases that are lost in the process. The purpose of this Document is to analyse these problems to determine areas for improvement and to emphasize one of the basic principles for the success of the programmes: continuous training for the interdisciplinary team. The result of the review process carried out by CODEPEH has been drafted as Recommendations for updating the Programmes with the evidence of the last decade, including advances in screening technology, the impact of the present knowledge on congenital infection by cytomegalovirus, genetic hearing loss research and control systems of lost to follow-up cases, treatment and follow up.

Personal utility of genomic sequencing for infants with congenital deafness

Decisions about genetic testing have traditionally been based on clinical utility and cost, but personal utility is increasingly recognized when assessing the value of testing. Whole exome sequencing (WES) was offered to a population cohort of 106 infants diagnosed with congenital hearing loss. Parents could choose to receive results relating to hearing loss only or also learn additional information about childhood-onset conditions (medically nonactionable and/or actionable). This study aimed to quantify the personal utility of WES for parents after a diagnosis of hearing loss in their child. Parents completed surveys pretest (63/106), after hearing loss results (52/106) and after receiving additional information (47/72). Open-ended responses from all three surveys (N = 67) were analyzed using inductive content analysis. Answers to questions regarding the value of sequencing to parents were analyzed and collated. Parents placed high value on diagnostic WES for hearing loss but had different perspectives on the personal utility of additional information. Diagnostic results provided certainty while the choice to learn additional information about childhood-onset disorders was associated with empowerment. WES also represented an opportunity to promote their child's best interests. Results provide insights into the utility of WES for the indication of congenital deafness and for genomic newborn screening broadly.

Exome Sequencing for Isolated Congenital Hearing Loss: A Cost-Effectiveness Analysis

OBJECTIVES/HYPOTHESIS

To assess the relative cost-effectiveness of exome sequencing for isolated congenital deafness compared with standard care.

STUDY DESIGN

Incremental cost-effectiveness and cost-benefit analyses were undertaken from the perspective of the Australian healthcare system using an 18-year time horizon.

METHODS

A decision tree was used to model the costs and outcomes associated with exome sequencing and standard care for infants presenting with isolated congenital deafness.

RESULTS

Exome sequencing resulted in an incremental cost of AU$1,000 per child and an additional 30 diagnoses per 100 children tested. The incremental cost-effectiveness ratio was AU$3,333 per additional diagnosis. The mean societal willingness to pay for exome sequencing was estimated at AU$4,600 per child tested relative to standard care, resulting in a positive net benefit of AU$3,600. Deterministic and probabilistic sensitivity analyses confirmed the cost-effectiveness of exome sequencing.

CONCLUSIONS

Our findings demonstrate the cost-effectiveness of exome sequencing in congenital hearing loss, through increased diagnostic rate and consequent improved process of care by reducing or ceasing diagnostic investigation or facilitating targeted further investigation. We recommend equitable funding for exome sequencing in infants presenting with isolated congenital hearing loss.

LEVEL OF EVIDENCE

N/A. Laryngoscope, 131:E2371-E2377, 2021.

Exome sequencing in newborns with congenital deafness as a model for genomic newborn screening: the Baby Beyond Hearing project

PURPOSE

Genomic newborn screening raises practical and ethical issues. Evidence is required to build a framework to introduce this technology safely and effectively. We investigated the choices made by a diverse group of parents with newborns when offered tiered genomic information from exome sequencing.

METHODS

This population-derived cohort comprised infants with congenital deafness. Parents were offered exome sequencing and choice regarding the scope of analysis. Options were choice A, diagnostic analysis only; choice B, diagnostic analysis plus childhood-onset diseases with medical actionability; or choice C, diagnostic analysis plus childhood-onset diseases with or without medical actionability.

RESULTS

Of the 106 participants, 72 (68%) consented to receive additional findings with 29 (27.4%) selecting choice B and 43 (40.6%) opting for choice C. Family size, ethnicity, and age of infant at time of recruitment were the significant predictors of choice. Parents who opted to have additional findings analysis demonstrated less anxiety and decisional conflict.

CONCLUSIONS

These data provide evidence from a culturally diverse population that choice around additional findings is important and the age of the infant when this choice is offered impacts on their decision. We found no evidence that offering different levels of genomic information to parents of newborns has a negative psychological impact.

Exome sequencing in infants with congenital hearing impairment: a population-based cohort study

Congenital hearing impairment (HI) is the most common sensory impairment and can be isolated or part of a syndrome. Diagnosis through newborn hearing screening and management through early intervention, hearing aids and cochlear implantation is well established in the Australian setting; however understanding the genetic basis of congenital HI has been missing. This population-derived cohort comprised infants with moderate-profound bilateral HI born in the 2016-2017 calendar years, detected through newborn hearing screening. Participants were recruited through an integrated paediatric, otolaryngology and genetics HI clinic and offered whole exome sequencing (WES) on a HiSeq4000 or NextSeq500 (Illumina) platform with a targeted average sequencing depth of 100x and chromosome microarray on the Illumina Infinium core exome-24v1.2 platform. Of those approached, 68% (106/156) consented to participate. The rate of genetic diagnosis was 56% (59/106), significantly higher than standard of care (GJB2/6 sequencing only), 21% (22/106). There were clinical implications for the 106 participants: 36% required no further screening, 9% had tailored screening initiated, 2% were offered treatment and 4% had informed care for a complex neurodevelopmental syndrome. WES in this cohort demonstrates the range of diagnoses associated with congenital HI and confirms the genetic heterogeneity of congenital HI. The high diagnostic yield and clinical implications emphasises the need for genomic sequencing to become standard of care.