Lauren Chad

Introduction: Genomic testing allows for the identification of disease-causing genetic variants and may also reveal secondary findings (SF) unrelated to the reason for testing. As the list of medically actionable genes continues to grow, it is important to understand the impact of these findings on clinical care and patient experience, particularly in paediatric settings. This work will generate novel evidence on the clinical, patient, family and system impacts of medically actionable SF generated from genomic testing. Methods and analysis: This mixed-methods, prospective, observational study will describe the impacts of SF on clinical care and the patient and family experience. Participants include probands and/or parents of probands who receive SF (ie, cases), clinicians involved in managing their care and controls matched 2:1 to cases based on age group, phenotype and primary genomic testing result. We aim to enrol 50 cases and 100 controls among those who receive genomic testing through Genome-wide Sequencing Ontario or other local sequencing initiatives in Ontario, Canada. Clinicians involved in follow-up care will complete questionnaires related to risk assessment, medical recommendations and clinical utility of SF post-result disclosure and one year later. Patient questionnaires will record health service use and psychological outcomes (ie, personal utility, empowerment) every 6 months for 2 years. These data will be compared between cases and controls using parametric tests. Cases will be invited to a qualitative interview to learn about their experiences. Data will be analysed using quantitative and qualitative techniques, triangulating datasets to enhance the validity and depth of the findings. Ethics and dissemination: This study is approved by the Clinical Trials Ontario (CTO) Research Ethics Review System (REB# CTO 3655). We plan to present our results to academic, patient, clinician and decision-maker audiences through articles and presentations at provincial, national and international meetings.

Rapid genomic sequencing (rGS) is increasingly used in neonatal and paediatric intensive care units (ICUs) to inform diagnosis and guide management of critically ill infants and children. Although rGS has a high diagnostic yield and potential to influence treatment and care planning decisions, little is known about how families experience rGS in the ICU and the emotional and contextual factors influencing their testing-related decisions. We conducted semi-structured interviews with twenty-three parents of infants who consented to rGS in an ICU at two tertiary hospitals in Toronto, Ontario, Canada; all interviews took place in close proximity to the decision to pursue rGS. Parents’ experiences with rGS and the related genetics consultation demonstrated a complex interplay of emotional, pragmatic, relational, and temporal ‘sense-making’ to grasp what was happening. Overall, parents felt overwhelmed in the ICU. Some de-prioritized genetic testing compared to other aspects of care while others reflected negatively or ambivalently on rGS or felt that it was implicitly expected that they pursue it. We conclude that an rGS approach tailored to the ICU setting is needed. Consideration should be given to distributing complex decisions (such as those relating to primary vs. secondary findings) across multiple briefer visits, and alleviating decisional burden by reframing rGS as one of the many shared decisions made with families in this setting.

Disorders of GABRA3 , the only epilepsy-associated GABA _A receptor subunit gene on the X chromosome, have eluded clinical clarity due to ambiguous inheritance patterns and variable phenotypes. The long-standing assumption that all pathogenic variants cause loss of function further obscured genotype–phenotype relationships and hindered progress. Here, we curated a cohort of individuals with a GABRA3 variant, integrating deep phenotyping, genotyping, family history, and electrophysiology with a targeted mouse model. Among 43 individuals with 19 GABRA3 variants, functional analyses revealed gain- and loss-of-function effects, each linked to distinct clinical profiles. Gain-of-function variants were associated with severe, treatment-resistant epilepsy and profound intellectual disability, disproportionately affecting males, who were often nonambulant and had cortical visual impairment. Loss-of-function variants produced milder phenotypes, with epilepsy rarely observed; affected males showed behavioral issues and language delay, while females were unaffected carriers. Our gain-of-function ( Gabra3 ^Q242L/+ ) mouse model mirrored these sex-specific differences, showing increased seizure susceptibility, early death, and marked cortical hyperexcitability. These insights resolve longstanding uncertainties surrounding GABRA3 and redefine how X-linked disorders are interpreted. They demonstrate that it is the functional impact of a variant, not its mere presence, that determines whether a condition manifests dominantly or recessively. This distinction carries important implications for genetic counseling, precision medicine, and the broader interpretation of X-linked neurodevelopmental disorders.

Genetic disorders commonly share features such as developmental delays, cognitive impairment, and behavioral challenges, yet many conditions also present unique dysmorphic features that distinguish them. Performing a thorough medical and family history and a detailed physical exam with attention to dysmorphic features is often the first step toward arriving at a genetic diagnosis. Synthesizing a differential diagnosis from the information gathered helps to guide the genetic testing strategy. Challenges to recognizing a disorder include the breadth of the clinician's prior experience, the lack of distinctive dysmorphology or overlapping dysmorphology in some conditions, atypical presentations, and difficulties identifying phenotypes across different ancestries. In cases where such challenges exist, advanced facial recognition technology can help the consulting expert by directing a more efficient test strategy. We present 17 cases involving 19 patients, including one pair of affected siblings and one case involving a child and her affected mother, for which DeepGestalt, the technology powering Face2Gene, changed medical geneticists' testing decisions. These cases illustrate how this form of artificial intelligence can provide clinical utility through influencing providers' genetic testing recommendations in real time.

The aim of this document is to provide an updated statement from the Canadian College of Medical Geneticists (CCMG) regarding the current state and some future considerations on the collection, distribution, and storage of genomic information within electronic health records (EHRs), including which aspects of genomic data might warrant special attention. The original version of this document was written by the CCMG Ethics and Public Policy committee in 2010 based on data collected via an online survey of the CCMG membership at the time. It is updated here to reflect the current state of healthcare in 2024, where EHRs are almost ubiquitously used, and genomic medicine has expanded in its breadth and scope. The document was circulated to the general membership for review and feedback and has been approved by the CCMG Board of Directors.

We describe the unexpected challenges pediatricians may experience when children conceived with assisted reproduction are diagnosed with a rare genetic condition. A local case series triggered a dialogue between many stakeholders with varied expertise. Indeed, diagnosing a genetic disease in a child conceived by embryo, egg, or sperm donation is becoming more common now that genetic testing and in vitro fertilization (IVF) are readily accessible. However, how and whether to share that information with other stakeholders in the gamete donation process has not been fully explored, and the clinical responsibilities of the treating clinician remain ill-defined. This work centers on a patient with a confirmed diagnosis of X-linked nephrogenic diabetes insipidus. Ultimately, we found the same AVPR2 mutation in two children from two families conceived by egg donation. It led to multigenerational cascade diagnoses in the family of the shared, anonymous egg donor. First, we review current genetic testing practices in gamete donation and third-party reproduction. Then, we provide an overview of relevant genomic, ethical, legal, and psychosocial considerations for sharing relevant genomic information. Finally, and to maximize the best interests of genetic relatives, we discuss how a pediatrician can play a role in the early disclosure of relevant clinical information to all stakeholders in the gamete donation process, starting with the fertility clinic. While these clinical cases are cast in a Canadian context, we submit that its important lessons generally apply to medical systems of nearly all developed countries, broadly defined.

Background Advances in technology and knowledge have facilitated both an increase in the number of patient variants reported and variants reclassified. While there is currently no duty to recontact for reclassified genetic variants, there may be a responsibility. The purpose of this clinical practice advisory document is to provide healthcare practitioners guidance for recontact of previously identified and classified variants, suggest methods for recontact, and principles to consider, taking account patient safety, feasibility, ethical considerations, health service capacity and resource constraints. The target audience are practitioners who order genetic testing, follow patients who have undergone genetic testing and those analysing and reporting genetic testing. Methods A multidisciplinary group of laboratory and ordering clinicians, patient representatives, ethics and legal researchers and a genetic counsellor from the Canadian Association of Genetic Counsellors reviewed the existing literature and guidelines on responsibility to recontact in a clinical context to make recommendations. Comments were collected from the Canadian College of Medical Geneticists (CCMG) Education, Ethics, and Public Policy, Clinical Practice and Laboratory Practice committees, and the membership at large. Results Following incorporation of feedback, and external review by the Canadian Association of Genetic Counsellors and patient groups, the document was approved by the CCMG Board of Directors. The CCMG is the Canadian organisation responsible for certifying laboratory and medical geneticists who provide medical genetics services, and for establishing professional and ethical standards for clinical genetics services in Canada. Conclusion The document describes the ethical and practical factors and suggests a shared responsibility between patients, ordering clinician and laboratory practitioners.

SATB2 -associated syndrome (SAS) is caused by pathogenic variants in SATB2 , which encodes an evolutionarily conserved transcription factor. Despite the broad range of phenotypic manifestations and variable severity related to this syndrome, haploinsufficiency has been assumed to be the primary molecular explanation. In this study, we describe eight individuals with SATB2 variants that affect p.Gly392 (four women, age range 2–16 years; p.Gly392Arg, p.Gly392Glu and p.Gly392Val). Of these, individuals with p.Gly392Arg substitutions were found to have more severe neurodevelopmental phenotypes based on an established rubric scoring system when compared with individuals with p.Gly392Glu, p.Gly392Val and other previously reported causative SATB2 missense variants. Consistent with the observations at the phenotypic level, using human cell-based and model organism functional data, we documented that while all three described p.Gly392 variants affect the same residue and seem to all have a partial loss-of-function effect, some effects on SATB2 protein function appear to be variant-specific. Our results indicate that genotype–phenotype correlations in SAS are more complex than originally thought, and variant-specific genotype–phenotype correlations are needed.

Introduction Genetic testing is used across medical disciplines leading to unprecedented demand for genetic services. This has resulted in excessive waitlists and unsustainable pressure on the standard model of genetic healthcare. Alternative models are needed; e-health tools represent scalable and evidence-based solution. We aim to evaluate the effectiveness of the Genetics Navigator, an interactive patient-centred digital platform that supports the collection of medical and family history, provision of pregenetic and postgenetic counselling and return of genetic testing results across paediatric and adult settings. Methods and analysis We will evaluate the effectiveness of the Genetics Navigator combined with usual care by a genetics clinician (physician or counsellor) to usual care alone in a randomised controlled trial. One hundred and thirty participants (adults patients or parents of paediatric patients) eligible for genetic testing through standard of care will be recruited across Ontario genetics clinics. Participants randomised into the intervention arm will use the Genetics Navigator for pretest and post-test genetic counselling and results disclosure in conjunction with their clinician. Participants randomised into the control arm will receive usual care, that is, clinician-delivered pretest and post-test genetic counselling, and results disclosure. The primary outcome is participant distress 2 weeks after test results disclosure. Secondary outcomes include knowledge, decisional conflict, anxiety, empowerment, quality of life, satisfaction, acceptability, digital health literacy and health resource use. Quantitative data will be analysed using statistical hypothesis tests and regression models. A subset of participants will be interviewed to explore user experience; data will be analysed using interpretive description. A cost-effectiveness analysis will examine the incremental cost of the Navigator compared with usual care per unit reduction in distress or unit improvement in quality of life from public payer and societal perspectives. Ethics and dissemination This study was approved by Clinical Trials Ontario. Results will be shared through stakeholder workshops, national and international conferences and peer-reviewed journals. Trial registration number NCT06455384.

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.