Utility of genetics for risk stratification in pediatric hypertrophic cardiomyopathy.

Children with hypertrophic cardiomyopathy (HCM) experience sudden cardiac death (SCD) and other life-threatening events. We assessed if affected gene and variant burden predict outcomes. Patients <18 years old with primary HCM with a pathogenic variant or variant of uncertain significance in cardiomyopathy genes were included. Association of gene and variant number and type with freedom from major adverse cardiac events (MACE), that is, ICD insertion, myectomy, aborted SCD, transplantation or death, was assessed by Cox regression. A total of 98 of 155 gene-tested patients carried a non-benign variant. The primary affected gene was MYH7 in 35% (MYH7+) and MYBPC3 in 49% (MYBPC3+). MYH7+ patients had earlier disease onset and higher risk of MACE (hazard ratio 2.7, 95% CI 1.3-5.7). Risk of MACE was also higher in patients with multiple variants (n = 16) (HR 2.5, CI: 1.1-5.9) compared to a propensity score-matched single variant subset, after adjustment for primary gene, and in patients with de novo (n = 18) vs inherited variants (HR 5.7, CI: 2.6-12.7). Affected gene (eg, MYH7), higher variant burden and de novo variant status are independently associated with earlier onset and higher frequency of adverse outcomes in pediatric HCM, highlighting the importance of genetic risk stratification in HCM.

Clinical genetic testing in pediatric cardiomyopathy: Is bigger better?

BACKGROUND: For clinical genetic testing of cardiomyopathy (CMP), current guidelines do not address which gene panels to use: targeted panels specific to a CMP phenotype or expanded (panCMP) panels that include genes associated with multiple phenotypic subtypes. AIM: Our objective was to assess the clinical utility of targeted versus panCMP panel testing in pediatric CMPs. METHODS: 151 pediatric patients with primary hypertrophic (n = 66), dilated (n = 64), restrictive (n = 8), or left-ventricular non-compaction (n = 13) CMP who underwent clinical genetic panel testing at a single centre were included. PanCMP (n = 47) and targeted panel testing (n = 104) were compared for yield of pathogenic variants and variants of unknown significance (VUS). RESULTS: Pathogenic variants were identified in 26% of patients, 42% had indeterminate results (only VUS detected), and 32% had negative results. Yield was lower (15%) in panCMP vs. targeted panel testing (32%) (P = .03) in all CMP subtypes. VUS detection was higher with panCMP (87%) than targeted panel testing (30%) (P <.0001). PanCMP panel testing only identified pathogenic variants in genes that overlapped targeted panels. CONCLUSION: PanCMP testing did not increase diagnostic yield compared to targeted panel testing. Until accuracy of variant interpretation with panCMP panels improves, targeted panels may be suitable for clinical testing in pediatric CMP.

Parents perspectives on whole genome sequencing for their children: qualified enthusiasm?

OBJECTIVE: To better understand the consequences of returning whole genome sequencing (WGS) results in paediatrics and facilitate its evidence-based clinical implementation, we studied parents' experiences with WGS and their preferences for the return of adult-onset secondary variants (SVs)-medically actionable genomic variants unrelated to their child's current medical condition that predict adult-onset disease. METHODS: We conducted qualitative interviews with parents whose children were undergoing WGS as part of the SickKids Genome Clinic, a research project that studies the impact of clinical WGS on patients, families, and the healthcare system. Interviews probed parents' experience with and motivation for WGS as well as their preferences related to SVs. Interviews were analysed thematically. RESULTS: Of 83 invited, 23 parents from 18 families participated. These parents supported WGS as a diagnostic test, perceiving clear intrinsic and instrumental value. However, many parents were ambivalent about receiving SVs, conveying a sense of self-imposed obligation to take on the 'weight' of knowing their child's SVs, however unpleasant. Some parents chose to learn about adult-onset SVs for their child but not for themselves. CONCLUSIONS: Despite general enthusiasm for WGS as a diagnostic test, many parents felt a duty to learn adult-onset SVs. Analogous to 'inflicted insight', we call this phenomenon 'inflicted ought'. Importantly, not all parents of children undergoing WGS view the best interests of their child in relational terms, thereby challenging an underlying justification for current ACMG guidelines for reporting incidental secondary findings from whole exome and WGS.

The SickKids Genome Clinic: developing and evaluating a pediatric model for individualized genomic medicine.

Our increasing knowledge of how genomic variants affect human health and the falling costs of whole-genome sequencing are driving the development of individualized genomic medicine. This new clinical paradigm uses knowledge of an individual's genomic variants to anticipate, diagnose and manage disease. While individualized genetic medicine offers the promise of transformative change in health care, it forces us to reconsider existing ethical, scientific and clinical paradigms. The potential benefits of pre-symptomatic identification of at-risk individuals, improved diagnostics, individualized therapy, accurate prognosis and avoidance of adverse drug reactions coexist with the potential risks of uninterpretable results, psychological harm, outmoded counseling models and increased health care costs. Here we review the challenges, opportunities and limits of integrating genomic analysis into pediatric clinical practice and describe a model for implementing individualized genomic medicine. Our multidisciplinary team of bioinformaticians, health economists, health services and policy researchers, ethicists, geneticists, genetic counselors and clinicians has designed a 'Genome Clinic' research project that addresses multiple challenges in pediatric genomic medicine--ranging from development of bioinformatics tools for the clinical assessment of genomic variants and the discovery of disease genes to health policy inquiries, assessment of clinical care models, patient preference and the ethics of consent.

Predictive genetic testing for adult-onset disorders in minors: a critical analysis of the arguments for and against the 2013 ACMG guidelines.

The publication of the ACMG recommendations has reignited the debate over predictive testing for adult-onset disorders in minors. Response has been polarized. With this in mind, we review and critically analyze this debate. First, we identify long-standing inconsistencies between consensus guidelines and clinical practice regarding risk assessment for adult-onset genetic disorders in children using family history and molecular analysis. Second, we discuss the disparate assumptions regarding the nature of whole genome and exome sequencing underlying arguments of both supporters and critics, and the role these assumptions play in the arguments for and against reporting. Third, we suggest that implicit differences regarding the definition of best interests of the child underlie disparate conclusions as to the best interests of children in this context. We conclude by calling for clarity and consensus concerning the central foci of this debate.

Views from the clinic: Healthcare provider perspectives on whole genome sequencing in paediatrics.

Whole genome sequencing (WGS) is a transformative technology which promises improved diagnostic rates compared to conventional genetic testing strategies and tailored approaches to patient care. Due to the practical and ethical complexities associated with using WGS, particularly in the paediatric context, input from a broad spectrum of healthcare providers can guide implementation strategies. We recruited healthcare providers from the largest paediatric academic health science centre in Canada and conducted semi-structured qualitative interviews, exploring experiences with and perceptions of the opportunities and challenges associated with WGS. Interview transcripts were coded and analyzed thematically. Interviews were completed with 14 genetics professionals (geneticists and genetic counsellors) and 15 non-genetics professionals (physician sub-specialists and nurses). Genetics professionals ordered genetic tests more often and reported greater confidence on pre- and post-test genetic counselling compared to non-genetics professionals. Most healthcare providers endorsed WGS when a more specific test was either not available or not likely to yield a diagnosis. While genetics professionals raised concerns regarding the time demands associated with reviewing WGS variants, non-genetics professionals reflected concerns about knowledge and training. Providers' position on reporting secondary variants to parents drew upon but was not limited to the concept of best interests. Taken together, understanding practical and principled matters of WGS from healthcare providers' perspectives can guide ongoing efforts to implement WGS in paediatrics.

Pregnancy and perinatal outcomes after assisted reproduction: a comparative study.

BACKGROUND: Increasing use of fertility therapy has elicited concerns regarding adverse effects for expectant mothers and the health of children thus conceived. AIMS: To study the risk of adverse perinatal outcomes, birth defects and pregnancy complications following assisted reproductive technology (ART). METHODS: Questionnaire-based study involving 1,524 children and 1,182 pregnancies conceived following in vitro fertilisation (IVF) in two units. Outcomes were compared with the general population. RESULTS: In the study group versus the general population; multi-foetal gestations, 26 versus 2%; singleton preterm delivery and low birth weight, 8.7 and 6.4 versus 4.3 and 4%, respectively; non-lethal congenital malformation rate, 2.6 versus 2.1%; placenta praevia, 2.8 versus 0.5%. CONCLUSIONS: Multi-foetal gestations remain the principal cause of adverse perinatal outcomes after ART. Singleton ART pregnancies have an increased risk of preterm delivery and low birth weight at term. Non-lethal congenital malformation rates are not increased following ART. Placenta praevia is increased following ART.

Assisted reproductive therapies and imprinting disorders--a preliminary British survey.

BACKGROUND: Recent reports have suggested a higher risk of Beckwith-Wiedemann syndrome (BWS) and Angelman syndrome (AS) after assisted reproductive technologies (ARTs), but it is unclear whether this might also apply to other disorders of genomic imprinting. METHODS: We contacted families of children with BWS, AS, Prader-Willi syndrome (PWS) and transient neonatal diabetes mellitus (TNDM) to determine use of ART. RESULTS: A statistically significant increased frequency of ART in children with BWS was confirmed [2.9%, 95% confidence interval (CI) 1.4-6.3% vs 0.8% expected] but there was no significant association with PWS or TNDM. Consideration of the molecular subgroup of BWS and AS suggested the feasibility of association with ART. CONCLUSIONS: These differences may relate to variations in (i) the molecular mechanisms for disordered imprinting in the different disorders and (ii) the susceptibility of specific imprinting control regions to ART-associated methylation alterations (epimutations).