Citywide Rapid Whole-Genome Sequencing Achieves 53% Diagnostic Yield in Critically Ill Children, Reshaping PICU Standard of Care
核心洞察
The Dubai LITTLE FALCON program deployed citywide rapid whole-genome sequencing (rWGS) across NICUs and PICUs, enrolling 100 critically ill pediatric patients from 18 countries with a median turnaround of 3.4 days.
rWGS achieved a 53% diagnostic yield (95% CI 43.3–62.5%), significantly outperforming standard-of-care testing (30%) and driving clinical management changes in 53% of patients.
Diagnostic yield reached 80% among children of consanguineous parents, reflecting the high burden of autosomal recessive disease in this Middle Eastern and Asian population.
A citywide rapid whole-genome sequencing (rWGS) program implemented across Dubai's neonatal and pediatric intensive care units returned actionable molecular diagnoses in a median of 3.4 days, achieving a 53% diagnostic yield and prompting clinically meaningful changes in care for more than half of critically ill children, according to a study published in Nature Medicine. The LITTLE FALCON program, which enrolled 100 critically ill pediatric patients representing 18 Middle Eastern and Asian countries, demonstrates that rWGS has crossed the threshold from investigational tool to standard-of-care clinical infrastructure.
Program Design and Referral Workflow
The program established a cross-institutional referral network within Dubai Health (搜索), with neonatal referrals coordinated through the maternity center (Latifa Hospital) hosting the central NICU, and pediatric referrals beyond the neonatal period routed through the central PICU at Al Jalila Children's Hospital. A multidisciplinary team comprising neonatologists, pediatricians, and genetic counselors jointly identified eligible patients from the centralized NICU and PICU (approximately 110 beds).
Case selection followed predefined inclusion criteria focused on patients with suspected monogenic disorders where a rapid diagnosis was anticipated to inform acute clinical management. Patient enrollment rose steadily over time, from 40 patients in year 1 to 73 patients in year 3, accompanied by a reduction in median time from admission to referral (7 days in year 1 to 5 days in year 3), attributable to greater awareness and education about the program.
The end-to-end rWGS protocol operated within a genomic sequencing facility accredited by the College of American Pathologists (CAP), with variant interpretation conducted in accordance with American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology (AMP) guidelines. The program was initially co-sponsored by Dubai Health (搜索) and Illumina, and is transitioning to a sustainable funding model with government coverage for UAE nationals and support for non-nationals through insurance or philanthropic organizations including the Al Jalila Foundation (搜索).
Patient Demographics and Genetic Architecture
The median age at presentation was 17 days (interquartile range 0–151 days), with 53% being neonates and 87% under 1 year of age. Sixty-two patients were referred from the NICU and 38 from the PICU. Half of patients presented with single-system phenotypes, with metabolic (n = 15), neurologic (n = 10), and cardiovascular (n = 8) presentations most recurrent, while the remainder exhibited multiple congenital anomalies or complex multisystemic presentations.
Genomic analysis revealed that 52% of patients demonstrated evidence of parental relatedness, ranging from distant shared ancestries (16.3%) to close consanguineous unions (35.7%) such as double first cousins. Parental relatedness rates reached 52.5% among Middle Eastern families and 55.8% among Asian families, largely driven by Pakistani families sharing similar consanguineous marriage practices.
Diagnostic Performance and Turnaround Time
The median turnaround time from sample submission to reporting was 81.1 hours (IQR 69.9–108.6 hours), equivalent to 3.4 calendar days, with the fastest result achieved in 47.7 hours. Sequencing and bioinformatics analysis accounted for the largest proportion of total turnaround time (median 51.7 hours).
Out of 100 enrolled patients, 53 received at least one molecular diagnosis related to the primary presentation, yielding an overall diagnostic rate of 53% (95% CI 43.3–62.5%). The diagnostic yield was comparable between NICU (32/62; 51.6%) and PICU (21/38; 55.3%) groups. Five patients (5%) had dual molecular diagnoses involving two or more pathogenic variants affecting distinct loci.
Diagnostic yield varied by clinical indication, with the highest observed in metabolic disorders at 80%. Yield was significantly enriched among children born to consanguineous parents, with rWGS establishing a molecular diagnosis in 80% of those cases (28/35), more than double the 34% yield observed in children of unrelated parents (16/47) (Fisher's exact test, P < 0.001).
Most diagnoses (41/58 or 70.7%) were attributable to autosomal recessive conditions, driven predominantly by homozygous variants (62.1%). Autosomal dominant disorders represented 13.8%, X-linked conditions 3.4%, and chromosomal anomalies 12.1% of diagnoses.
Clinical Utility and Impact on Care
Beyond diagnostic clarification, rWGS was associated with clinically meaningful shifts in care trajectory in 53% of critically ill patients (53/100), including those with (45/53; 85%) or without (8/47; 17%) molecular diagnoses. Across the cohort, rWGS findings were associated with targeted pharmacologic or dietary intervention in 36% of patients, procedure- or surgery-defining decisions in 13%, consolidation of diagnostic pathways in 43%, subspecialty referrals in 37%, and redirection toward palliative care in 9%.
Using the adapted Clinician-reported Genetic testing Utility InDEx questionnaire in ICU (C-GUIDE ICU), cumulative scores ranged from 2 to 16 with a median of 9. Scores were consistently higher among genetically diagnosed patients relative to undiagnosed patients (median 12 versus 2, P < 0.00001). rWGS led to immediate changes in disease trajectories in 16% of patients, with favorable outcomes in 8% and end-of-life decisions in 8%.
Illustrative cases included a 2-week-old ventilator-dependent newborn in whom identification of a pathogenic PHOX2B (搜索) variant established congenital central hypoventilation syndrome (搜索) within 72.7 hours, and an 18-day-old infant with persistent severe hypoglycemia in whom genotype-directed classification of focal ABCC8 (搜索)-associated disease within 55 hours supported early definitive surgical intervention.
Comparison with Standard-of-Care Testing
A retrospective control cohort of 100 infants and children admitted to the NICU/PICU during 2018–2022, prior to rWGS implementation, served as a benchmark. Standard-of-care testing was associated with significantly prolonged diagnostic timelines (median 38 days, IQR 23–53 days, versus 3.4 days; Mann–Whitney U test, P < 0.001) and lower diagnostic yield (30%, 95% CI 21.3–40.2%, versus 53%; Fisher's exact test, P < 0.01). Changes in clinical management were also significantly lower in control cases (18% versus 53%, P < 0.001), and C-GUIDE ICU scores were significantly lower (median 9 versus 0, P < 0.00001).
The current cost of rWGS in this setting, benchmarked against commercial laboratories in the USA, is approximately US$3,500 per case, resulting in a cost per diagnosis of US$6,603—markedly lower than earlier reported median costs of US$9,239 per proband and US$23,602 per diagnosis.
Regulatory and Operational Implications
The program's scale carries regulatory significance for sponsors in rare disease and pediatric drug development. The FDA's 2022 final guidance on Clinical Decision Support Software distinguishes software qualifying as a medical device from software supporting a clinician's independent judgment, but AI-driven variant interpretation layers that convert genomic data into clinical action recommendations sit in an uncomfortable middle space.
This tension becomes a regulatory enforcement question as cities scale rWGS across multiple ICUs simultaneously. On August 24, 2026, GeneDx (搜索) announced findings from a study published in Genetics in Medicine detailing hospital-wide adoption of rapid genome sequencing at Seattle Children's (搜索), covering over 1,000 pediatric inpatients across the neonatal ICU, pediatric ICU, and cardiac ICU.
For sponsors running rare disease trials, this creates immediate protocol design challenges: eligibility windows shrink when rWGS returns results in 3.4 days rather than a 30-day diagnostic workup; randomization integrity may be affected when sites stratify patients on genomic data not accounted for in statistical analysis plans; and institutional review boards will question whether informed consent addresses incidental findings generated by hospital clinical workflows.
Study Limitations
Middle Eastern populations remain underrepresented in global genomic reference datasets, and widely used variant databases are disproportionately weighted toward European ancestry. This imbalance constrains pathogenicity evidence for region-specific alleles and may bias variant interpretation toward conservative classification, suggesting the reported diagnostic yield likely represents a lower bound of the true Mendelian disease burden. The eligibility criteria also exclude nonviable neonates, representing potentially missed opportunities to identify pathogenic variants associated with lethal genetic conditions that families could use to avoid future recurrence.
The study was approved by the Mohammed Bin Rashid University institutional review board (MBRU IRB no. DAHC-MBRU-IRB-2023-008) and the Dubai Scientific Research Ethics Committee (DSREC-08/2025_17), with written informed consent obtained from parents following genetic counseling.