The rapid accrual of knowledge in genomic medicine has prompted the reanalysis of preexisting data. 1,2 We clinically reanalyzed data from two patient series that had undergone diagnostic proband-only exome sequencing.

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Importance: While congenital malformations and genetic diseases are a leading cause of early infant death, the contribution of single-gene disorders in this group is undetermined. Objective: To determine the diagnostic yield and utility of clinical exome sequencing in critically ill infants. Design, setting, participants: Clinical exome sequencing was performed on 278 unrelated infants within the first 100 days of life, admitted to Texas Children’s Hospital in Houston, over a period of five years, between December 2011 and January 2017. Exome sequencing types included proband exome, trio exome, and critical trio exome, a rapid genomic assay for seriously-ill infants. Main outcomes and measures: Indications for testing, diagnostic yield of clinical exome sequencing, turnaround time, molecular findings, patient age at diagnosis, and impact on medical management in a group of critically ill infants suspected to have genetic disorders. Results: Clinical indications for exome sequencing included a wide range of medical concerns. Overall, molecular diagnosis was achieved in 102/278 infants by clinical exome sequencing with a diagnostic yield of 36.7%. The diagnosis affected medical management in 53/102 (52.0%) of infants, with substantial impact on informed redirection of care, initiation of new subspecialist care, medication/dietary modifications, and furthering life-saving procedures in select patients. Critical trio exome revealed a molecular diagnosis in 32/63 infants (50.8%) at 33.1±5.6 days of life with turnaround time (TAT) of 13.0 ± 0.4 days. Clinical care was altered by the diagnosis in 23/32 (71.9%) patients. The diagnostic yield, patient age at diagnosis, and medical impact in the group that underwent critical trio exome is significantly different comparing to regular exome testing. For deceased infants (n=81), genetic disorders were molecular diagnosed in 39 (48.1%) by exome sequencing with implications for recurrence risk counseling. Conclusions and relevance: Exome sequencing is a powerful tool for the diagnostic evaluation of critically ill infants with suspected monogenic disorders in the neonatal and pediatric ICUs, leading to notable impact on clinical decision-making.

BackgroundExome sequencing is now being incorporated into clinical care for pediatric and adult populations, but its integration into prenatal diagnosis has been more limited. One reason for this is the paucity of information about the clinical utility of exome sequencing in the prenatal setting.MethodsWe retrospectively reviewed indications, results, time to results (turnaround time, TAT), and impact of exome results for 146 consecutive “fetal exomes” performed in a clinical diagnostic laboratory between March 2012 and November 2017. We define a fetal exome as one performed on a sample obtained from a fetus or a product of conception with at least one structural anomaly detected by prenatal imaging or autopsy. Statistical comparisons were performed using Fisher’s exact test.ResultsPrenatal exome yielded an overall molecular diagnostic rate of 32% (n = 46/146). Of the 46 molecular diagnoses, 50% were autosomal dominant disorders (n = 23/46), 41% were autosomal recessive disorders (n = 19/46), and 9% were X-linked disorders (n = 4/46). The molecular diagnostic rate was highest for fetuses with anomalies affecting multiple organ systems and for fetuses with craniofacial anomalies. Out of 146 cases, a prenatal trio exome option designed for ongoing pregnancies was performed on 62 fetal specimens, resulting in a diagnostic yield of 35% with an average TAT of 14 days for initial reporting (excluding tissue culture time). The molecular diagnoses led to refined recurrence risk estimates, altered medical management, and informed reproductive planning for families.ConclusionExome sequencing is a useful diagnostic tool when fetal structural anomalies suggest a genetic etiology, but other standard prenatal genetic tests did not provide a diagnosis.Electronic supplementary materialThe online version of this article (10.1186/s13073-018-0582-x) contains supplementary material, which is available to authorized users.

BACKGROUND. Transcriptome sequencing (RNA-seq) improves diagnostic rates in individuals with suspected Mendelian conditions to varying degrees, primarily by directing the prioritization of candidate DNA variants identified on exome or genome sequencing (ES/GS). Here we implemented an RNA-seq guided method to diagnose individuals across a wide range of ages and clinical phenotypes. METHODS. One hundred fifteen undiagnosed adult and pediatric patients with diverse phenotypes and 67 family members (182 total individuals) underwent RNA-seq from whole blood and fibroblasts at the Baylor College of Medicine (BCM) Undiagnosed Diseases Network (UDN) clinical site from 2014-2020. We implemented a workflow to detect outliers in gene expression and splicing for cases that remained undiagnosed despite standard genomic and transcriptomic analysis. RESULTS. The transcriptome-directed approach resulted in a diagnostic rate of 12% across the entire cohort, or 17% after excluding cases solved on ES/GS alone. Newly diagnosed conditions included Koolen-de Vries syndrome (KANSL1), Renpenning syndrome (PQBP1), TBCKassociated encephalopathy, NSD2and CLTC-related intellectual disability, and others, all with negative conventional genomic testing, including ES and chromosomal microarray (CMA). Fibroblasts exhibited higher and more consistent expression of clinically relevant genes than whole blood. In solved cases with RNA-seq from both tissues, the causative defect was missed in blood in half the cases but none from fibroblasts. CONCLUSION. For our cohort of undiagnosed individuals with suspected Mendelian conditions, transcriptome-directed genomic analysis facilitated diagnoses, primarily through the identification of variants missed on ES and CMA. 4 TRIAL REGISTRATION. Not applicable.