Biomedical subjects

Gregory Costain

Publications and source records attributed to Gregory Costain.

6 recordsLinked to original sources

PubMed2025

Screening rare genetic diagnoses for amenability to bespoke antisense oligonucleotide therapy development: A retrospective cohort study.

PURPOSE: To estimate the proportion of molecular genetic diagnoses in a real-world, phenotypically heterogeneous patient cohort that are amenable to antisense oligonucleotide (ASO) treatment. METHODS: We retrospectively applied the N=1 Collaborative's Variant Assessments toward Eligibility for Antisense Oligonucleotide Treatment guidelines to all diagnostic variants found by clinical genome-wide sequencing at a single pediatric hospital in 532 patients over a 6-year period. Variants were classified as either "eligible," "likely eligible," "unlikely eligible," or "not eligible" in relation to the different ASO approaches, or "unable to assess." RESULTS: In total, 25 unique variants across 26 patients (4.9% of 532 patients) were eligible or likely eligible for ASO treatment at a molecular genetic level, via canonical exon skipping (4), splice correction (3), or messenger RNA knockdown (19). Only 8 of these molecular genetic diagnoses were made within a year of symptom onset. After considering disease and delivery related factors, 11 diagnoses were still considered candidates for bespoke ASO development. CONCLUSION: A meaningful proportion of genetic diagnoses identified by genome-wide sequencing may be amenable to ASO treatment. These results underscore the importance of timely diagnosis, and the proactive identification and accelerated functional testing of genetic variants amenable to ASO treatments.

Humans↗

PubMed2025

Comparing the performance of exome and genome sequencing for rare disease diagnostics: A randomized implementation effectiveness trial.

PURPOSE: Exome sequencing (ES) and genome sequencing (GS) can improve rare disease diagnosis but are not routinely available in many jurisdictions. To inform implementation, we report on a randomized implementation effectiveness trial comparing ES and GS. METHODS: Eligible trios were randomized to receive ES or GS in the same clinically accredited laboratory. Patient-level data on diagnostic utility and turnaround times were collected. Outcomes were compared statistically between clinically important subgroups. RESULTS: Of 1048 patients, 68.5% had syndromic intellectual disability/developmental delay (ID/DD) and 20.5% had multisystem disorders without ID/DD. Most had prior genetic test(s) that were nondiagnostic (95.5%), and of these, 91.6% included chromosome microarray. Diagnostic yields were 33.8% and 33.6%, for ES (n = 526) and GS (n = 522), respectively. Within sequencing groups, diagnostic results were more frequent among those with ID/DD than those without (P < .005). For routine (ie, nonexpedited) patients (n = 1020), 87.0% were reported in <12 weeks, and the mean turnaround time was 55.5 days (SD: 24.0). Turnaround time for ES and GS did not differ; however, result type (P < .001) and age of onset (P < .005) significantly affected turnaround time. CONCLUSION: Findings provide robust evidence of diagnostic utility and timeliness of ES and GS and will inform policy related to the organization, delivery, and reimbursement of clinical-grade genome diagnostics for rare diseases.

Adolescent↗

PubMed2025

A microcosting and cost consequence analysis from a randomized controlled trial comparing genome sequencing with exome sequencing for genetic diagnosis.

PURPOSE: Diagnosing rare diseases is costly. The objectives were to microcost exome (ES) and genome sequencing (GS) trios and estimate the incremental costs of GS per additional diagnosis from an institutional payer perspective. METHODS: Trios (proband plus biological parents) that are referred for sequencing were randomly assigned to ES or GS. Laboratory workflow and sequencing were microcosted. Total and category cost per trio were estimated probabilistically. Effectiveness was expressed as diagnostic yield (rates of diagnostic or partially diagnostic variants detected). Incremental costs and effectiveness were calculated. RESULTS: The mean total cost per trio was CAD 2888.79 (95% CI 2567.72, 3492.72) for ES (n = 329) and 4364.02 (95% CI 3984.94, 5013.67) for GS (n = 324). Reagents accounted for 34% and 61% of total costs for ES and GS, respectively. The incremental cost of GS was 1475.23. The diagnostic yield was 35.9% for ES and 32.7% for GS with a difference of 0.032 (95% CI: -0.041, 0.104, P value .397). CONCLUSION: GS demonstrated higher costs and a similar diagnostic yield to ES but was limited by technical capabilities at the time of the study. The study provides comprehensive costs for the economic evaluation comparing alternative diagnostic pathways and impetus for further evaluating variants uniquely detectable by GS.

Humans↗

PubMed2025

Pathogenic XPO1 variants cause a dominant neurodevelopmental disorder.

PURPOSE: XPO1 functions in key cellular processes, including nucleo-cytoplasmic export and mitosis. The gene is deleted in a subset of patients with the 2p15p16.1 microdeletion syndrome; however, no monogenic XPO1-related disorder has been described to date. METHODS: We collected clinical data of individuals with de novo XPO1 variants through online matchmaking. We used Drosophila to study XPO1 function in development and habituation learning. RESULTS: A total of 22 individuals met the criteria to be included in the main study cohort. Of these, half have putative loss-of-function variants, and half have coding variants (10 missense and 1 in-frame deletion variant). We found an overlapping phenotype, consistent with a monogenic neurodevelopmental disorder. We demonstrate XPO1 functions in development by ubiquitous and neuron-specific knockdown in Drosophila. GABAergic neuron specific knockdown flies demonstrated impaired habituation. CONCLUSION: Our results establish XPO1 as a novel dominant monogenic neurodevelopmental disorder gene and demonstrate a central role for XPO1 in development.

Exportin 1 Protein↗

PubMed2025

The development and usability of 'The Genetics Navigator': a digital solution for adult and paediatric clinical genetics services.

Clinical genetic services address diverse genetic testing needs, but there is no comprehensive digital solution to meet this variety. We aimed to develop and test the usability of the Genetics Navigator (GN), a platform designed to enhance genetic services for paediatric and adult patients. The GN prototype was created with input from a patient and clinician advisory board, informed by prior research. Usability testing involved genetics patients (N = 14), parents of paediatric patients (N = 4), and the general public (N = 10). Participants provided feedback using the 'think aloud' method when using the platform. We used the System Usability Scale (SUS) for quantitative evaluation. Qualitative data were coded by platform section, item, and identified key areas for improvement. Building on the Genetics Adviser platform, we added video and written content for various genetic conditions and patient groups, including pre-test education, counselling, decision support, history collection, post-test result disclosure, and management. Key feedback during rounds of usability testing emphasized the need for a supportive design, seamless workflow, and engaging experience of the tool. The tool was modified to reflect the feedback, and the GN achieved an average SUS score of 87.7 ± 10.9 (N = 28), indicating above-average usability. Future research will evaluate its clinical and cost-effectiveness in a randomized trial.

Humans↗

PubMed2025

Mainstreaming of clinical genetic testing: A conceptual framework.

PURPOSE: Demand for genetic testing is increasing across medicine, whereas the genetics workforce remains stable. In response, mainstreaming models are being introduced, in which nongeneticist clinicians are increasingly involved in the genetic testing pathway. Because a standardized approach would facilitate evaluation and optimal patient care, a unified framework is warranted. METHODS: Through a focus group with clinical genetics experts, a conceptual framework for the mainstreaming of clinical genetic testing is proposed. Through a consensus process, experts elucidated the steps in the diagnostic care pathway and defined a set of variables that influence which mainstreaming model is best suited to specific patient care scenarios. RESULTS: A total of 35 individuals representing 20 distinct clinical genetics services and all Canadian provinces participated in the development of the framework. The framework describes 4 generalizable mainstreaming models of care, each with varying levels of involvement of the clinical genetics service in the diagnostic care pathway. CONCLUSION: This framework will help guide clinical teams in the design and evaluation of mainstreaming efforts. It is critical that these programs are evaluated and shared in a standardized way so that we can implement strategies that allow optimal utilization of genetics resources and improve patient care.

Humans↗