Contribution of malformations and genetic disorders to mortality in a children's hospital

Ethical challenges and justice concerns for infants and children with life-limiting conditions and significant disability, including trisomy 13 and 18

Some life-limiting conditions associated with significant neurodevelopmental impairment, such as trisomy 13/18, have historically been considered lethal, thus medical or surgical treatments would be inappropriate. Evolving literature has shown that early death is not universal, and though all who survive with trisomy 13/18 will have significant impairments, some experience a positive quality of life. The presence of bias impacts counseling as well as what interventions are offered and/or provided to families of a child with anticipated significant disability. Shared decision-making processes should include parents receiving all relevant information about comfort care as well as available, indicated, and ethically permissible medical/surgical interventions. Ethical frameworks can help clarify which options would be permissible to offer or withhold on an individualized basis. Clinicians are encouraged to be open to revisiting past and sometimes long-established practices regarding patients with disability. A willingness to change should not be perceived as an indictment of past practice.

Palliative Care Outcomes for Critically ill Children After Rapid Whole Genome Sequencing

Objectives: Clinical utility of rapid whole genome sequencing (rWGS) has been reported in 30-70% of pediatric ICU patients who receive a molecular diagnosis. Rapid molecular diagnostic techniques have been increasingly integrated into critical care, yet the influence of genetic test results on palliative care related decision making is largely unknown. This study evaluates palliative care related outcomes after rWGS. Design: Retrospective chart review Setting: Tertiary children's hospital Patients: Acutely ill children ≤ 18 years of age who received rWGS due to suspected genetic disease between July 2016 and November 2019 Interventions: rWGS with associated precision medicine Measurements and Main Results: 536 patients underwent rWGS, of whom 152 (28.4%) received a molecular diagnosis. Diagnostic rWGS was associated with more code status modifications, an increase in palliative care inpatient consultations, and greater enrollment in home-based palliative services. A comparison of diagnostic and nondiagnostic rWGS groups where palliative decisions were made prior to reporting of genomic testing results did not identify differences between the groups. In the subset of patients who had palliative care interventions (n = 57, 53% with diagnostic rWGS), time to palliative care consultation and time to compassionate extubation were shorter for patients with rWGS-based diagnoses (Kaplan-Meier method, P = .008; P = .015). Significantly more patients in this subgroup with diagnostic rWGS received home-based palliative care (Chi-squared, P = .025, 95% CI [-0.47, -0.05]). Univariate Poisson regression indicated that diagnostic rWGS is associated with significantly fewer emergency visits, PICU admissions, and unplanned intubations. Conclusions: Diagnostic rWGS correlates with more rapid engagement of pediatric palliative care services, higher enrollment rates in home-based palliative care, and shorter time to compassionate extubation. Further studies are needed with larger cohort sizes and validated pediatric palliative care outcome measurement tools to accurately determine if this change in care is driven by the underlying condition or knowledge of a molecular diagnosis.

Rapid Whole-Genome Sequencing as a First-Line Test Is Likely to Significantly Reduce the Cost of Acute Care in a Private Payer System

BACKGROUND

Genetic disorders are a leading contributor to morbidity and mortality in neonatal and pediatric intensive care units. Rapid whole-genome sequencing (rWGS) has demonstrated improved clinical outcomes and reduced costs of care. The objective of this study was to predict the effect of rWGS on healthcare spending if implemented as a first-line diagnostic test in the Blue Shield of California (BSC) private payer system.

METHODS

This study applied private payer reimbursement methods and rates to clinical outcomes of rWGS on pediatric inpatient care as determined by a previous study of publicly insured infants in Project Baby Bear. BSC patients who were clinically similar to the Project Baby Bear cohort were identified by matching on diagnosis-related group and severity of illness. Payment data from these BSC patients was used to estimate the financial impact of clinical outcomes resulting from rWGS testing in a commercially insured pediatric population.

RESULTS

The analysis estimated a reduction of $5.8 million to $7.8 million in inpatient payments due to an estimated 457 to 592 avoided inpatient days due to rWGS results. With an estimated cost of sequencing at $2.7 million for the entire cohort (n = 184), the financial impact of rWGS as a first-tier test in the intensive care unit resulted in estimated net savings to BSC of $16 730 to $28 061 per patient sequenced.

CONCLUSIONS

Implementation of rWGS using the protocols established in Project Baby Bear is likely to result in significant reductions in healthcare spending among privately insured patients.

Exome sequencing of 18,994 ethnically diverse patients with suspected rare Mendelian disorders

We investigated the effectiveness of exome sequencing (ES) in diagnosing ethnically diverse patients with rare genetic disorders. A total of 18,994 patients referred to a single reference laboratory for ES between 2020 and 2022 were studied for the diagnostic rate and factors influencing the diagnostic rate. The overall diagnostic rate was 31.8%. Dermatological disorders, skeletal disorders, and neurodevelopmental disorders disease categories, early age-of-onset, presence of consanguinity, and the presence of parental sequencing data were found to be correlated with a higher diagnostic rate. Nearly 68K variants were identified in our dataset at a higher frequency than that observed in gnomAD 4.0. Of these, 507 variants could be classified as likely benign, representing 0.04% of non-benign variants in ClinVar (507/1,433,904) and 0.20% of the non-benign ClinVar variants observed at least once in our cohort (507/276,777). The overall diagnostic rate is comparable to that observed in other large cohort studies with less diverse ethnic backgrounds.

Characteristics and management of pediatric patients with a genetic disorder and malformations in a pediatric emergency department

BACKGROUND

Genetic diseases are associated with a high mortality rate. Although numerous studies have examined this topic in pediatric patients in the pediatric intensive care setting, related data from the pediatric emergency care setting are scarce.

OBJECTIVES

The present study aimed to describe the characteristics and management of pediatric patients with a genetic disorder and malformations in a pediatric emergency department (ED).

METHODS

The present, retrospective study was conducted at a tertiary children's hospital in Japan. The medical records of patients with a previously diagnosed genetic disorder who presented to the ED of the study center between January 1 and June 30, 2019, were reviewed. Patients with an uncertain diagnosis who visited the ED for follow-up consultation were excluded.

RESULTS

During the study period, 17,856 patients had visited the ED. Of these, 2094 had a genetic disorder. Forty-three patients were excluded, and 2051 patients were included in the final analysis. The median age was 46 months (interquartile range [IQR]: 19-96 months). The most common genetic disorder was isolated malformation (56.4%), followed by chromosomal abnormalities, multiple malformations, and single-gene disorders at 11.7%, 10.4%, and 10.1%, respectively. Common diagnostic categories were infectious diseases (25.9%), GI diseases (14.1%), and trauma (11.2%). The admission rate was 19.5%, and the median length of hospitalization was 7 days (IQR: 4-11 days). The mortality rate was only 0.2%.

CONCLUSION

Pediatric patients with a genetic disorder had a high admission rate and a long period of hospitalization, but their mortality rate was relatively low.

Whole genome sequencing as a first-tier diagnostic test for infants in neonatal intensive care units: A pilot study in Brazil

In this pilot study, we aimed to evaluate the feasibility of whole genome sequencing (WGS) as a first-tier diagnostic test for infants hospitalized in neonatal intensive care units in the Brazilian healthcare system. The cohort presented here results from a joint collaboration between private and public hospitals in Brazil considering the initiative of a clinical laboratory to provide timely diagnosis for critically ill infants. We performed trio (proband and parents) WGS in 21 infants suspected of a genetic disease with an urgent need for diagnosis to guide medical care. Overall, the primary indication for genetic testing was dysmorphic syndromes (n = 14, 67%) followed by inborn errors of metabolism (n = 6, 29%) and skeletal dysplasias (n = 1, 5%). The diagnostic yield in our cohort was 57% (12/21) based on cases that received a definitive or likely definitive diagnostic result from WGS analysis. A total of 16 pathogenic/likely pathogenic variants and 10 variants of unknown significance were detected, and in most cases inherited from an unaffected parent. In addition, the reported variants were of different types, but mainly missense (58%) and associated with autosomal diseases (19/26); only three were associated with X-linked diseases, detected in hemizygosity in the proband an inherited from an unaffected mother. Notably, we identified 10 novel variants, absent from public genomic databases, in our cohort. Considering the entire diagnostic process, the average turnaround time from enrollment to medical report in our study was 53 days. Our findings demonstrate the remarkable utility of WGS as a diagnostic tool, elevating the potential of transformative impact since it outperforms conventional genetic tests. Here, we address the main challenges associated with implementing WGS in the medical care system in Brazil, as well as discuss the potential benefits and limitations of WGS as a diagnostic tool in the neonatal care setting.

Wales Infants' and childreN's Genome Service (WINGS): providing rapid genetic diagnoses for unwell children

INTRODUCTION

This study reviews the first 3 years of delivery of the first National Health Service (NHS)-commissioned trio rapid whole genome sequencing (rWGS) service for acutely unwell infants and children in Wales.

METHODS

Demographic and phenotypic data were prospectively collected as patients and their families were enrolled in the Wales Infants' and childreN's Genome Service (WINGS). These data were reviewed alongside trio rWGS results.

RESULTS

From April 2020 to March 2023, 82 families underwent WINGS, with a diagnostic yield of 34.1%. The highest diagnostic yields were noted in skeletal dysplasias, neurological or metabolic phenotypes. Mean time to reporting was 9 days.

CONCLUSION

This study demonstrates that trio rWGS is having a positive impact on the care of acutely unwell infants and children in an NHS setting. In particular, the study shows that rWGS can be applied in an NHS setting, achieving a diagnostic yield comparable with the previously published diagnostic yields achieved in research settings, while also helping to improve patient care and management.

Current situation and prospect for the diagnosis and treatment of pediatric critical rare diseases in China

The onset of critical rare diseases (RDs) in children is rapid and dangerous, accompanied by a high mortality rate, which brings a heavy burden to both families and society. Multiple malformations, neuromuscular diseases, metabolic diseases, and heart diseases are the most common types of RDs in children of China, often manifesting with multiple organ dysfunction. At present, the diagnosis and treatment of critical RDs in children face challenges such as prolonged diagnosis time, a high misdiagnosis rate, limited treatment modalities, and a significant disease burden. However, with the progress in genetic testing technology, the establishment of multidisciplinary diagnosis and treatment platforms, and the implementation of relevant RD policies in China, children with critical RDs will received enhanced medical services, experience improved prognoses, and reintegrate into social life.

A Rare Presentation of Edwards Syndrome in a Three-Month-Old Infant: A Case Report

Edwards syndrome, also known as trisomy 18, is a rare chromosomal disorder associated with multiple congenital anomalies and high morbidity. This report presents the case of a three-month-old female infant diagnosed with Edwards syndrome, presenting classic phenotypic features, including low-set ears, micrognathia, and a rocker bottom foot. The infant's condition was further complicated by cardiac abnormalities and respiratory distress, necessitating a comprehensive, multidisciplinary approach involving pediatricians, cardiologists, and orthopedic specialists. The diagnostic journey involved addressing challenges related to respiratory distress syndrome, bronchiolitis, and cardiac complications. The management approach underscored the significance of individualized care tailored to the patient's unique needs. Genetic counseling played a pivotal role in providing essential support to the family facing the complexities associated with Edwards syndrome. This case report highlights the intricacies of Edwards syndrome and contributes to the ongoing discourse on refining clinical strategies for enhanced care and compassionate support. Additionally, it emphasizes the need for further research to advance our understanding of this condition and guide future interventions.

Diagnostic genomic sequencing in critically ill children

Rare genetic diseases are a major cause of severe illnesses and deaths in new-borns and infants. Disease manifestation in critically ill children may be atypical or incomplete, making a monogenetic disease difficult to diagnose clinically. Rapid exome or genome ("genomic") sequencing in critically ill children demonstrated profound diagnostic and clinical value, and there is growing evidence that the faster a molecular diagnosis is established in such children, the more likely clinical management is influenced positively. An early molecular diagnosis enables treatment of critically ill children with precision medicine, has the potential to improve patient outcome and leads to healthcare cost savings. In this review, we outline the status quo of rapid genomic sequencing and possible future implications.

A holistic approach to maximise diagnostic output in trio exome sequencing

Introduction

Rare genetic diseases are a major cause for severe illness in children. Whole exome sequencing (WES) is a powerful tool for identifying genetic causes of rare diseases. For a better and faster assessment of the vast number of variants that are identified in the index patient in WES, parental sequencing can be applied ("trio WES").

Methods

We assessed the diagnostic rate of routine trio WES including analysis of copy number variants in 224 pediatric patients during an evaluation period of three years.

Results

Trio WES provided a diagnosis in 67 (30%) of all 224 analysed children. The turnaround time of trio WES analysis has been reduced significantly from 41 days in 2019 to 23 days in 2021. Copy number variants could be identified to be causative in 10 cases (4.5%), underlying the importance of copy number variant analysis. Variants in three genes which were previously not associated with a clinical condition (GAD1, TMEM222 and ZNFX1) were identified using the matching tool GeneMatcher and were part of the first description of a new syndrome.

Discussion

Trio WES has proven to have a high diagnostic yield and to shorten the process of identifying the correct diagnosis in paediatric patients. Re-evaluation of all 224 trio WES 1-3 years after initial analysis did not establish new diagnoses. Initiating (trio) WES as a first-tier diagnostics including copy number variant detection should be considered as early as possible, especially for children treated in ICU, if a monogenetic disease is suspected.

Combinatorial batching of DNA for ultralow-cost detection of pathogenic variants

BACKGROUND

Next-generation sequencing (NGS) based population screening holds great promise for disease prevention and earlier diagnosis, but the costs associated with screening millions of humans remain prohibitive. New methods for population genetic testing that lower the costs of NGS without compromising diagnostic power are needed.

METHODS

We developed double batched sequencing where DNA samples are batch-sequenced twice - directly pinpointing individuals with rare variants. We sequenced batches of at-birth blood spot DNA using a commercial 113-gene panel in an explorative (n = 100) and a validation (n = 100) cohort of children who went on to develop pediatric cancers. All results were benchmarked against individual whole genome sequencing data.

RESULTS

We demonstrated fully replicable detection of cancer-causing germline variants, with positive and negative predictive values of 100% (95% CI, 0.91-1.00 and 95% CI, 0.98-1.00, respectively). Pathogenic and clinically actionable variants were detected in RB1, TP53, BRCA2, APC, and 19 other genes. Analyses of larger batches indicated that our approach is highly scalable, yielding more than 95% cost reduction or less than 3 cents per gene screened for rare disease-causing mutations. We also show that double batched sequencing could cost-effectively prevent childhood cancer deaths through broad genomic testing.

CONCLUSIONS

Our ultracheap genetic diagnostic method, which uses existing sequencing hardware and standard newborn blood spots, should readily open up opportunities for population-wide risk stratification using genetic screening across many fields of clinical genetics and genomics.

Education and Training of Non-Genetics Providers on the Return of Genome Sequencing Results in a NICU Setting

To meet current and expected future demand for genome sequencing in the neonatal intensive care unit (NICU), adjustments to traditional service delivery models are necessary. Effective programs for the training of non-genetics providers (NGPs) may address the known barriers to providing genetic services including limited genetics knowledge and lack of confidence. The SouthSeq project aims to use genome sequencing to make genomic diagnoses in the neonatal period and evaluate a scalable approach to delivering genome sequencing results to populations with limited access to genetics professionals. Thirty-three SouthSeq NGPs participated in a live, interactive training intervention and completed surveys before and after participation. Here, we describe the protocol for the provider training intervention utilized in the SouthSeq study and the associated impact on NGP knowledge and confidence in reviewing, interpreting, and using genome sequencing results. Participation in the live training intervention led to an increased level of confidence in critical skills needed for real-world implementation of genome sequencing. Providers reported a significant increase in confidence level in their ability to review, understand, and use genome sequencing result reports to guide patient care. Reported barriers to implementation of genome sequencing in a NICU setting included test cost, lack of insurance coverage, and turn around time. As implementation of genome sequencing in this setting progresses, effective education of NGPs is critical to provide access to high-quality and timely genomic medicine care.

Exome and Whole Genome Sequencing in the Neonatal Intensive Care Unit

The role of genomic sequencing (exome and whole genome) in the neonatal intensive care unit (NICU) has changed with advances in technology and bioinformatics in the last decade. Evidence from 18 retrospective and prospective studies of exome and whole genome sequencing in pediatric intensive care settings has demonstrated an average diagnostic yield of close to 40% and an immediate impact on clinical management in more than 20% of patients tested, and the highest clinical utility was in the perinatal setting. Genomic sequencing, when indicated, should be the standard of care for patients in the NICU.

Expanded carrier screening in the United States: A systematic evidence review exploring client and provider experiences

The aim of carrier screening is to identify prospective parents at risk of having a pregnancy affected with an autosomal recessive or X-linked disorder. Though minimal guideline-based screening is available, expanded carrier screening (ECS) is quickly becoming a feasible option for the general population due to its growing availability and affordability. However, the impact of ECS on clients and providers remains relatively unexplored. We performed a systematic evidence review to identify publications describing client-, provider-, and test-related outcomes. We searched several biomedical databases for articles published between January 1, 2003 and May 31, 2021. Studies were eligible for inclusion if they described genetic counseling and/or genetic testing for carrier screening (minimal guideline-based or ECS) in a prenatal or preconception setting in the United States. Title and abstract screening were performed using the Raayan web application or customized Google Forms. Full-text review and data extraction of included articles were performed using custom Google Forms. Two researchers performed a multistep selection process independently for validation purposes. Of 5413 unique articles screened, 36 studies were included with several studies contributing to multiple outcomes. Twenty described outcomes relating to patients/clients, 10 described provider-based outcomes, and 16 described test-based outcomes. Findings suggest that client and provider perceptions of ECS and minimal guideline-based carrier screening are multifaceted. Though clients have expressed desire for ECS, clinical uptake and impact on reproductive decision-making varies. Additionally, though genetic counselors seem to be comfortable with ECS, most other reproductive care providers seem to prefer minimal guideline or ancestry-based screening due to perceived barriers, such as time needed for ECS results disclosure and follow-up, as well as the desire to have panels set by professional societies/recommendations. There are limitations within the gathered literature, leading to potential uncertainty in the generalizability of our review. We outline several recommendations for future studies, including the need to examine variant interpretation and use of next-generation sequencing.

Mid-Term Outcomes of Heart Transplantation in Children with Genetic Disorders

BACKGROUND

Many congenital heart diseases (CHD) are associated with genetic defects. Children with complex CHD often develop heart failure, requiring heart transplant. Given the broad spectrum of genetic pathologies and dearth of transplants performed in these children, little is known regarding their outcomes.

METHODS

We conducted a retrospective review of heart transplants performed at a high-volume center from 2007-2021. Patients were separated into pathogenic molecular and copy number variants, aneuploidies, and variants of uncertain significance, and compared to those without known genetic diagnoses. Variables included genetic diagnoses, bridge-to-transplant approach, preoperative comorbidities, operative characteristics, and postoperative complications. Outcomes included ICU-free days to 28 days, hospital mortality, survival, rejection, re-transplantation, and educational status at latest follow-up.

RESULTS

223 patients were transplanted over the study period: 9.9% (22/223) had pathogenic molecular variants, 4.5% (10/223) had copy number variants, 1.8% (4/223) had aneuploidies, and 9.0% (20/223) had variants of uncertain significance. The most common anomalies were Turner syndrome (n=3) and 22q11.2 deletion syndrome (n=2). Children with aneuploidies had higher rates of hepatic dysfunction and hypothyroidism, while those with pathogenic copy number variants had higher rates of preoperative gastrostomy and stroke. Children with aneuploidies were intubated longer post-transplant, with greater need for re-intubation, and had the fewest ICU-free days. Mortality and mean survival did not differ. At median follow-up of 4.4 (1.9-8.8) years, 89.7% (26/29) of survivors with pathogenic anomalies were attending or had graduated school.

CONCLUSIONS

Despite more preoperative comorbidities, mid-term outcomes following heart transplant in children with genetic syndromes and disorders are promising.

Congenital anomalies and genetic disorders in neonates and infants: a single-center observational cohort study

Neonates with genetic disorders or congenital anomalies (CA) contribute considerably to morbidity and mortality in neonatal intensive care units (NICUs). The objective of this study is to study the prevalence of genetic disorders in an academic level IV NICU. We retrospective collected and analyzed both clinical and genetic data of all 1444 infants admitted to the NICU of the Radboudumc (October 2013 to October 2015). Data were collected until infants reached at least 2 years of age. A total of 13% (194/1444) of the patients were genetically tested, and 32% (461/1444) had a CA. A total of 37% (72/194) had a laboratory-confirmed genetic diagnosis. In 53%, the diagnosis was made post-neonatally (median age = 209 days) using assays including exome sequencing. Exactly 63% (291/461) of the patients with CA, however, never received genetic testing, despite being clinically similar those who did.Conclusions: Genetic disorders were suspected in 13% of the cohort, but only confirmed in 5%. Most received their genetic diagnosis in the post-neonatal period. Extrapolation of the diagnostic yield suggests that up to 6% of our cohort may have remained genetically undiagnosed. Our data show the need to improve genetic care in the NICU for more inclusive, earlier, and faster genetic diagnosis to enable tailored management. What is Known: • Genetic disorders are suspected in many neonates but only genetically confirmed in a minority. • The presence of a genetic disorder can be easily missed and will often lead to a diagnostic odyssey requiring extensive evaluations, both clinically and genetically. What is New: • Different aspects of the clinical features and uptake of genetic test in a NICU cohort. • The need to improve genetic care in the NICU for more inclusive, earlier, and faster genetic diagnosis to enable tailored management.

Genetic neuromuscular disorders: what is the best that we can do?

The major advances in genetic neuromuscular disorders in the last 30 years have been: (a) identification of the genetic basis for hundreds of these disorders, (b) through knowing the genes, understanding their pathobiology and (c) subsequent implementation of evidence-based treatments for some of the disorders. New genomic technologies are providing precision diagnosis, mode of inheritance and likely prognosis for more patients than ever before. Parents of children with a genetic diagnosis can then use preimplantation or prenatal diagnosis to avoid having further affected children if they wish. But is this the best we can do for genetic neuromuscular disorders? Since the 1980s, it has been argued it would be better to identify Duchenne muscular dystrophy carrier mothers, rather than diagnose their affected sons. Carrier screening for recessive disorders can identify couples with a high chance of having affected children. It allows couples reproductive choice and can prevent infant morbidity and mortality and significant distress for families. Professional bodies in many countries now recommend prospective parents should be informed about carrier screening. Implementing and funding expensive therapies increases the cost-effectiveness of carrier screening, increasing its attractiveness to governments. Best practice for genetic neuromuscular disorders should include equitable access to carrier screening.

Clinical Utility of Rapid Exome Sequencing Combined With Mitochondrial DNA Sequencing in Critically Ill Pediatric Patients With Suspected Genetic Disorders

Genetic disorders are a frequent cause of hospitalization, morbidity and mortality in pediatric patients, especially in the neonatal or pediatric intensive care unit (NICU/PICU). In recent years, rapid genome-wide sequencing (exome or whole genome sequencing) has been applied in the NICU/PICU. However, mtDNA sequencing is not routinely available in rapid genetic diagnosis programs, which may fail to diagnose mtDNA mutation-associated diseases. Herein, we explored the clinical utility of rapid exome sequencing combined with mtDNA sequencing in critically ill pediatric patients with suspected genetic disorders. Rapid clinical exome sequencing (CES) was performed as a first-tier test in 40 critically ill pediatric patients (aged from 6 days to 15 years) with suspected genetic conditions. Blood samples were also collected from the parents for trio analysis. Twenty-six patients presented with neuromuscular abnormalities or other systemic abnormalities, suggestive of suspected mitochondrial diseases or the necessity for a differential diagnosis of other diseases, underwent rapid mtDNA sequencing concurrently. A diagnosis was made in 18 patients (45.0%, 18/40); three cases with de novo autosomal dominant variants, ten cases with homozygous or compound heterozygous variants, three cases with hemizygous variants inherited from mother, three cases with heterozygous variants inherited from either parent, and one case with a mtDNA mutation. The 18 patients were diagnosed with metabolic (n = 7), immunodeficiency (n = 4), cardiovascular (n = 2), neuromuscular (n = 2) disorders, and others. Genetic testing reports were generated with a median time of 5 days (range, 3–9 days). Thirteen patients that were diagnosed had an available medical treatment and resulted in a positive outcome. We propose that rapid exome sequencing combined with mitochondrial DNA sequencing should be available to patients with suspected mitochondrial diseases or undefined clinical features necessary for making a differential diagnosis of other diseases.

Project Baby Bear: Rapid precision care incorporating rWGS in 5 California children's hospitals demonstrates improved clinical outcomes and reduced costs of care

Genetic disorders are a leading contributor to mortality in neonatal and pediatric intensive care units (ICUs). Rapid whole-genome sequencing (rWGS)-based rapid precision medicine (RPM) is an intervention that has demonstrated improved clinical outcomes and reduced costs of care. However, the feasibility of broad clinical deployment has not been established. The objective of this study was to implement RPM based on rWGS and evaluate the clinical and economic impact of this implementation as a first line diagnostic test in the California Medicaid (Medi-Cal) program. Project Baby Bear was a payor funded, prospective, real-world quality improvement project in the regional ICUs of five tertiary care children's hospitals. Participation was limited to acutely ill Medi-Cal beneficiaries who were admitted November 2018 to May 2020, were <1 year old and within one week of hospitalization, or had just developed an abnormal response to therapy. The whole cohort received RPM. There were two prespecified primary outcomes-changes in medical care reported by physicians and changes in the cost of care. The majority of infants were from underserved populations. Of 184 infants enrolled, 74 (40%) received a diagnosis by rWGS that explained their admission in a median time of 3 days. In 58 (32%) affected individuals, rWGS led to changes in medical care. Testing and precision medicine cost $1.7 million and led to $2.2-2.9 million cost savings. rWGS-based RPM had clinical utility and reduced net health care expenditures for infants in regional ICUs. rWGS should be considered early in ICU admission when the underlying etiology is unclear.

Cost Efficacy of Rapid Whole Genome Sequencing in the Pediatric Intensive Care Unit

The diagnostic and clinical utility of rapid whole genome sequencing (rWGS) for critically ill children in the intensive care unit (ICU) has been substantiated by multiple studies, but comprehensive cost-effectiveness evaluation of rWGS in the ICU outside of the neonatal age group is lacking. In this study, we examined cost data retrospectively for a cohort of 38 children in a regional pediatric ICU (PICU) who received rWGS. We identified seven of 17 patients who received molecular diagnoses by rWGS and had resultant changes in clinical management with sufficient clarity to permit cost and quality adjusted life years (QALY) modeling. Cost of PICU care was estimated to be reduced by $184,846 and a total of 12.1 QALYs were gained among these seven patients. The total cost of rWGS for patients and families for the entire cohort (38 probands) was $239,400. Thus, the net cost of rWGS was $54,554, representing $4,509 per QALY gained. This quantitative, retrospective examination of healthcare utilization associated with rWGS-informed medicine interventions in the PICU revealed approximately one-third of a QALY gained per patient tested at a cost per QALY that was approximately one-tenth of that typically sought for cost-effective new medical interventions. This evidence suggests that performance of rWGS as a first-tier test in selected PICU children with diseases of unknown etiology is associated with acceptable cost-per-QALY gained.

An RCT of Rapid Genomic Sequencing among Seriously Ill Infants Results in High Clinical Utility, Changes in Management, and Low Perceived Harm

The second Newborn Sequencing in Genomic Medicine and Public Health (NSIGHT2) study was a randomized, controlled trial of rapid whole-genome sequencing (rWGS) or rapid whole-exome sequencing (rWES) in infants with diseases of unknown etiology in intensive care units (ICUs). Gravely ill infants were not randomized and received ultra-rapid whole-genome sequencing (urWGS). Herein we report results of clinician surveys of the clinical utility of rapid genomic sequencing (RGS). The primary end-point-clinician perception that RGS was useful- was met for 154 (77%) of 201 infants. Both positive and negative tests were rated as having clinical utility (42 of 45 [93%] and 112 of 156 [72%], respectively). Physicians reported that RGS changed clinical management in 57 (28%) infants, particularly in those receiving urWGS (p = 0.0001) and positive tests (p < 0.00001). Outcomes of 32 (15%) infants were perceived to be changed by RGS. Positive tests changed outcomes more frequently than negative tests (p < 0.00001). In logistic regression models, the likelihood that RGS was perceived as useful increased 6.7-fold when associated with changes in management (95% CI 1.8-43.3). Changes in management were 10.1-fold more likely when results were positive (95% CI 4.7-22.4) and turnaround time was shorter (odds ratio 0.92, 95% CI 0.85-0.99). RGS seldom led to clinician-perceived confusion or distress among families (6 of 207 [3%]). In summary, clinicians perceived high clinical utility and low likelihood of harm with first-tier RGS of infants in ICUs with diseases of unknown etiology. RGS was perceived as beneficial irrespective of whether results were positive or negative.

Genetics and pediatric hospital admissions, 1985 to 2017

PURPOSE

To determine the prevalence and sociodemographic and hospitalization history of genetic conditions in a sample of inpatients in a pediatric hospital in 2017, and to compare results with unpublished studies from 1985, 1995, and 2007.

METHODS

Two weeks of admissions were classified according to a pre-existing categorization, based on genetic etiology, encompassing chromosomal and monogenic conditions, multifactorial (MF) conditions, and no known genetic cause.

RESULTS

In 2017, 299 (16%) patients had chromosomal or monogenic conditions, 6-7% more than 2007 and 1995, but similar to 1985. Autosomal dominant (AD) conditions increased from <2% previously to 6% in 2017 (p < 0.001). MF conditions comprised the majority throughout, increasing from 45% to 54%. Age at admission was highest in autosomal recessive (AR) and X-linked categories in 1995, 2007, and 2017, reflected in their high number of previous admissions, while the AD, MF, and nongenetic categories were the youngest with similar lengths of stay and previous admissions.

CONCLUSION

Conditions with a genetic contribution account for over half of pediatric inpatients. Since 1985, there have been many changes in age at admission and length of stay, but it is the increasing prevalence of AR, AD, and MF conditions that is important when considering future service provision.

Clinical utility of 24-h rapid trio-exome sequencing for critically ill infants

Genetic diseases are a leading cause of death in infants in the intensive care setting; therefore, rapid and accurate genetic diagnosis is desired. To validate 24-h trio-exome sequencing (TES), samples from probands and their parents were processed by the AmpliSeq /Ion S5XL platform in a hospital clinical laboratory. Infants from the intensive care unit (ICU) suspected of having a genetic disease were enrolled. Regular and 24-h TES using the Agilent SureSelect capture kit/Illumina platform were performed on all samples in parallel. Of 33 enrolled infants, 23 received positive results with rapid TES, and an additional two diagnoses were achieved with regular TES. Among the 23 diagnosed patients, 10 experienced changes in medical management, such as hematopoietic stem cell transplant. Ten diagnosed cases were discharged prior to receiving the regular TES results; six received timely symptom control, and four withdrew medical support. Rapid TES enabled faster time to diagnosis, which resulted in an overall decrease in length of hospital stay. The 24-h TES can serve as a rapid response tool for patients with suspected monogenic disorders and can guide clinical decision-making in urgent cases.

Healthcare trajectory of children with rare bone disease attending pediatric emergency departments

BACKGROUND

Children with rare bone diseases (RBDs), whether medically complex or not, raise multiple issues in emergency situations. The healthcare burden of children with RBD in emergency structures remains unknown. The objective of this study was to describe the place of the pediatric emergency department (PED) in the healthcare of children with RBD.

METHODS

We performed a retrospective single-center cohort study at a French university hospital. We included all children under the age of 18 years with RBD who visited the PED in 2017. By cross-checking data from the hospital clinical data warehouse, we were able to trace the healthcare trajectories of the patients. The main outcome of interest was the incidence (IR) of a second healthcare visit (HCV) within 30 days of the index visit to the PED. The secondary outcomes were the IR of planned and unplanned second HCVs and the proportion of patients classified as having chronic medically complex (CMC) disease at the PED visit.

RESULTS

The 141 visits to the PED were followed by 84 s HCVs, giving an IR of 0.60 [95% CI: 0.48-0.74]. These second HCVs were planned in 60 cases (IR = 0.43 [95% CI: 0.33-0.55]) and unplanned in 24 (IR = 0.17 [95% CI: 0.11-0.25]). Patients with CMC diseases accounted for 59 index visits (42%) and 43 s HCVs (51%). Multivariate analysis including CMC status as an independent variable, with adjustment for age, yielded an incidence rate ratio (IRR) of second HCVs of 1.51 [95% CI: 0.98-2.32]. The IRR of planned second HCVs was 1.20 [95% CI: 0.76-1.90] and that of unplanned second HCVs was 2.81 [95% CI: 1.20-6.58].

CONCLUSION

An index PED visit is often associated with further HCVs in patients with RBD. The IRR of unplanned second HCVs was high, highlighting the major burden of HCVs for patients with chronic and severe disease.

Critical Trio Exome Benefits In-Time Decision-Making for Pediatric Patients With Severe Illnesses

OBJECTIVES

Critical illnesses caused by undiagnosed genetic conditions are challenging in PICUs. Whole-exome sequencing is a powerful diagnostic tool but usually costly and often fail to arrive at a final diagnosis in a short period. We assessed the feasibility of our whole-exome sequencing as a tool to improve the efficacy of rare diseases diagnosis for pediatric patients with severe illness.

DESIGN

Observational analysis.

METHOD

We employed a fast but standard whole-exome sequencing platform together with text mining-assisted variant prioritization in PICU setting over a 1-year period.

SETTING

A tertiary referral Children's Hospital in Taiwan.

PATIENTS

Critically ill PICU patients suspected of having a genetic disease and newborns who were suspected of having a serious genetic disease after newborn screening were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Around 50,000 to 100,000 variants were obtained for each of the 40 patients in 5 days after blood sampling. Eleven patients were immediately found be affected by previously reported mutations after searching mutation databases. Another seven patients had a diagnosis among the top five in a list ranked by text mining. As a whole, 21 patients (52.5%) obtained a diagnosis in 6.2 ± 1.1 working days (range, 4.3-9 d). Most of the diagnoses were first recognized in Taiwan. Specific medications were recommended for 10 patients (10/21, 47.6%), transplantation was advised for five, and hospice care was suggested for two patients. Overall, clinical management was altered in time for 81.0% of patients who had a molecular diagnosis.

CONCLUSIONS

The current whole-exome sequencing algorithm, balanced in cost and speed, uncovers genetic conditions in infants and children in PICU, which helps their managements in time and promotes better utilization of PICU resources.

Rapid Whole Genome Sequencing Has Clinical Utility in Children in the PICU

OBJECTIVES

Genetic disorders are a leading contributor to mortality in the neonatal ICU and PICU in the United States. Although individually rare, there are over 6,200 single-gene diseases, which may preclude a genetic diagnosis prior to ICU admission. Rapid whole genome sequencing is an emerging method of diagnosing genetic conditions in time to affect ICU management of neonates; however, its clinical utility has yet to be adequately demonstrated in critically ill children. This study evaluates next-generation sequencing in pediatric critical care.

DESIGN

Retrospective cohort study.

SETTING

Single-center PICU in a tertiary children's hospital.

PATIENTS

Children 4 months to 18 years admitted to the PICU who were nominated between July 2016 and May 2018.

INTERVENTIONS

Rapid whole genome sequencing with targeted phenotype-driven analysis was performed on patients and their parents, when parental samples were available.

MEASUREMENTS AND MAIN RESULTS

A molecular diagnosis was made by rapid whole genome sequencing in 17 of 38 children (45%). In four of the 17 patients (24%), the genetic diagnoses led to a change in management while in the PICU, including genome-informed changes in pharmacotherapy and transition to palliative care. Nine of the 17 diagnosed children (53%) had no dysmorphic features or developmental delay. Eighty-two percent of diagnoses affected the clinical management of the patient and/or family after PICU discharge, including avoidance of biopsy, administration of factor replacement, and surveillance for disorder-related sequelae.

CONCLUSIONS

This study demonstrates a retrospective evaluation for undiagnosed genetic disease in the PICU and clinical utility of rapid whole genome sequencing in a portion of critically ill children. Further studies are needed to identify PICU patients who will benefit from rapid whole genome sequencing early in PICU admission when the underlying etiology is unclear.

Genetic aetiology of early infant deaths in a neonatal intensive care unit

BACKGROUND

Congenital anomalies are the leading cause of early neonatal death in neonatal intensive care units (NICUs), but the genetic causes are unclear. This study aims to investigate the genetic causes of infant deaths in a NICU in China.

METHODS

Newborns who died in the hospital or died within 1 week of discharge were enrolled from Children's Hospital of Fudan University between January 1, 2015 and December 31, 2017. Whole exome sequencing was performed in all patients after death.

RESULTS

There were 223 deceased newborns with a median age at death of 13 days. In total, 44 (19.7%) infants were identified with a genetic finding, including 40 with single nucleotide variants (SNVs), two with CNVs and two with both SNVs and CNVs. Thirteen (31%, 13/42) patients with SNVs had medically actionable disorders based on genetic diagnosis, which included 10 genes. Multiple congenital malformation was identified as the leading genetic cause of death in NICUs with 13 newborns identified with variants in genes related to multiple congenital malformations. For newborns who died on the first day, the most common genetic cause of death was major heart defects, while metabolic disorders and respiratory failure were more common for newborns who died in the first 2 weeks.

CONCLUSION

Our study shows genetic findings among early infant deaths in NICUs and provides critical genetic information for precise genetic counselling for the families. Effective therapies enable the improvement of more than a quarter of newborns with molecular diagnoses if diagnosed in time.

The burden of rare diseases

The subject of rare disease numbers is rife with misconceptions, not just in websites and other layman's literature, but also in the medical literature. Various websites mention numbers that are not validated by any solid data, while in turn the medical literature cites the aforementioned websites as sources, thus perpetuating a number of myths about rare diseases and their burden. We review the existing literature on rare disease numbers, in an attempt to demystify the subject. Specifically, we summarize data pertaining to: (a) known number and cumulative prevalence of rare diseases; (b) rare disease-associated mortality; (c) rare disease-associated morbidity, including numbers on health care services related to rare diseases; and (d) orphan drug numbers.

Meta-analysis of the diagnostic and clinical utility of genome and exome sequencing and chromosomal microarray in children with suspected genetic diseases

Genetic diseases are leading causes of childhood mortality. Whole-genome sequencing (WGS) and whole-exome sequencing (WES) are relatively new methods for diagnosing genetic diseases, whereas chromosomal microarray (CMA) is well established. Here we compared the diagnostic utility (rate of causative, pathogenic, or likely pathogenic genotypes in known disease genes) and clinical utility (proportion in whom medical or surgical management was changed by diagnosis) of WGS, WES, and CMA in children with suspected genetic diseases by systematic review of the literature (January 2011–August 2017) and meta-analysis, following MOOSE/PRISMA guidelines. In 37 studies, comprising 20,068 children, diagnostic utility of WGS (0.41, 95% CI 0.34–0.48, I² = 44%) and WES (0.36, 95% CI 0.33–0.40, I² = 83%) were qualitatively greater than CMA (0.10, 95% CI 0.08–0.12, I² = 81%). Among studies published in 2017, the diagnostic utility of WGS was significantly greater than CMA (P < 0.0001, I² = 13% and I² = 40%, respectively). Among studies featuring within-cohort comparisons, the diagnostic utility of WES was significantly greater than CMA (P < 0.001, I² = 36%). The diagnostic utility of WGS and WES were not significantly different. In studies featuring within-cohort comparisons of WGS/WES, the likelihood of diagnosis was significantly greater for trios than singletons (odds ratio 2.04, 95% CI 1.62–2.56, I² = 12%; P < 0.0001). Diagnostic utility of WGS/WES with hospital-based interpretation (0.42, 95% CI 0.38–0.45, I² = 48%) was qualitatively higher than that of reference laboratories (0.29, 95% CI 0.27–0.31, I² = 49%); this difference was significant among studies published in 2017 (P < .0001, I² = 22% and I² = 26%, respectively). The clinical utility of WGS (0.27, 95% CI 0.17–0.40, I² = 54%) and WES (0.17, 95% CI 0.12–0.24, I² = 76%) were higher than CMA (0.06, 95% CI 0.05–0.07, I² = 42%); this difference was significant for WGS vs CMA (P < 0.0001). In conclusion, in children with suspected genetic diseases, the diagnostic and clinical utility of WGS/WES were greater than CMA. Subgroups with higher WGS/WES diagnostic utility were trios and those receiving hospital-based interpretation. WGS/WES should be considered a first-line genomic test for children with suspected genetic diseases.

Children with suspected genetic disease are more likely to receive a diagnosis when gene sequencing technologies are employed. At present, a microarray test for short pieces of missing or extra chromosomes (chromosomal microarray, CMA) is the recommended test for diagnosing genetic disease in children. The recent use of whole-genome sequencing (WGS) and whole-exome sequencing (WES) for diagnosing genetic disease prompted Stephen Kingsmore at Rady Children’s Institute for Genomic Medicine in San Diego, California, USA, and colleagues to examine the effectiveness of these methods compared with CMA. Analyses of studies comprising over 20,000 children showed that using WGS and WES increased the likelihood of diagnosis and led to a change in inpatient management to prevent or ameliorate adverse health outcomes. The authors advocate the use of WGS or WES as a first-line genomic test for genetic disease in children.

Genetic disorders and mortality in infancy and early childhood: delayed diagnoses and missed opportunities

PURPOSE

Infants admitted to a level IV neonatal intensive care unit (NICU) who do not survive early childhood are a population that is probably enriched for rare genetic disease; we therefore characterized their genetic diagnostic evaluation.

METHODS

This is a retrospective analysis of infants admitted to our NICU between 1 January 2011 and 31 December 2015 who were deceased at the time of records review, with age at death less than 5 years.

RESULTS

A total of 2,670 infants were admitted; 170 later died. One hundred six of 170 (62%) had an evaluation for a genetic or metabolic disorder. Forty-seven of 170 (28%) had laboratory-confirmed genetic diagnoses, although 14/47 (30%) diagnoses were made postmortem. Infants evaluated for a genetic disorder spent more time in the NICU (median 13.5 vs. 5.0 days; p = 0.003), were older at death (median 92.0 vs. 17.5 days; p < 0.001), and had similarly high rates of redirection of care (86% vs. 79%; p = 0.28).

CONCLUSION

Genetic disorders were suspected in many infants but found in a minority. Approximately one-third of diagnosed infants died before a laboratory-confirmed genetic diagnosis was made. This highlights the need to improve genetic diagnostic evaluation in the NICU, particularly to support end-of-life decision making.

The NSIGHT1-randomized controlled trial: rapid whole-genome sequencing for accelerated etiologic diagnosis in critically ill infants

Genetic disorders are a leading cause of morbidity and mortality in infants in neonatal and pediatric intensive care units (NICU/PICU). While genomic sequencing is useful for genetic disease diagnosis, results are usually reported too late to guide inpatient management. We performed an investigator-initiated, partially blinded, pragmatic, randomized, controlled trial to test the hypothesis that rapid whole-genome sequencing (rWGS) increased the proportion of NICU/PICU infants receiving a genetic diagnosis within 28 days. The participants were families with infants aged <4 months in a regional NICU and PICU, with illnesses of unknown etiology. The intervention was trio rWGS. Enrollment from October 2014 to June 2016, and follow-up until November 2016. Of all, 26 female infants, 37 male infants, and 2 infants of undetermined sex were randomized to receive rWGS plus standard genetic tests (n = 32, cases) or standard genetic tests alone (n = 33, controls). The study was terminated early due to loss of equipoise: 73% (24) controls received genomic sequencing as standard tests, and 15% (five) controls underwent compassionate cross-over to receive rWGS. Nevertheless, intention to treat analysis showed the rate of genetic diagnosis within 28 days of enrollment (the primary end-point) to be higher in cases (31%, 10 of 32) than controls (3%, 1 of 33; difference, 28% [95% CI, 10-46%]; p = 0.003). Among infants enrolled in the first 25 days of life, the rate of neonatal diagnosis was higher in cases (32%, 7 of 22) than controls (0%, 0 of 23; difference, 32% [95% CI, 11-53%];p = 0.004). Median age at diagnosis (25 days [range 14-90] in cases vs. 130 days [range 37-451] in controls) and median time to diagnosis (13 days [range 1-84] in cases, vs. 107 days [range 21-429] in controls) were significantly less in cases than controls (p = 0.04). In conclusion, rWGS increased the proportion of NICU/PICU infants who received timely diagnoses of genetic diseases.

Meta-analysis of the diagnostic and clinical utility of genome and exome sequencing and chromosomal microarray in children with suspected genetic diseases

Genetic diseases are leading causes of childhood mortality. Whole-genome sequencing (WGS) and whole-exome sequencing (WES) are relatively new methods for diagnosing genetic diseases, whereas chromosomal microarray (CMA) is well established. Here we compared the diagnostic utility (rate of causative, pathogenic, or likely pathogenic genotypes in known disease genes) and clinical utility (proportion in whom medical or surgical management was changed by diagnosis) of WGS, WES, and CMA in children with suspected genetic diseases by systematic review of the literature (January 2011-August 2017) and meta-analysis, following MOOSE/PRISMA guidelines. In 37 studies, comprising 20,068 children, diagnostic utility of WGS (0.41, 95% CI 0.34-0.48, I² = 44%) and WES (0.36, 95% CI 0.33-0.40, I² = 83%) were qualitatively greater than CMA (0.10, 95% CI 0.08-0.12, I² = 81%). Among studies published in 2017, the diagnostic utility of WGS was significantly greater than CMA (P < 0.0001, I² = 13% and I² = 40%, respectively). Among studies featuring within-cohort comparisons, the diagnostic utility of WES was significantly greater than CMA (P < 0.001, I² = 36%). The diagnostic utility of WGS and WES were not significantly different. In studies featuring within-cohort comparisons of WGS/WES, the likelihood of diagnosis was significantly greater for trios than singletons (odds ratio 2.04, 95% CI 1.62-2.56, I² = 12%; P < 0.0001). Diagnostic utility of WGS/WES with hospital-based interpretation (0.42, 95% CI 0.38-0.45, I² = 48%) was qualitatively higher than that of reference laboratories (0.29, 95% CI 0.27-0.31, I² = 49%); this difference was significant among studies published in 2017 (P < .0001, I² = 22% and I² = 26%, respectively). The clinical utility of WGS (0.27, 95% CI 0.17-0.40, I² = 54%) and WES (0.17, 95% CI 0.12-0.24, I² = 76%) were higher than CMA (0.06, 95% CI 0.05-0.07, I² = 42%); this difference was significant for WGS vs CMA (P < 0.0001). In conclusion, in children with suspected genetic diseases, the diagnostic and clinical utility of WGS/WES were greater than CMA. Subgroups with higher WGS/WES diagnostic utility were trios and those receiving hospital-based interpretation. WGS/WES should be considered a first-line genomic test for children with suspected genetic diseases.

Use of Exome Sequencing for Infants in Intensive Care Units: Ascertainment of Severe Single-Gene Disorders and Effect on Medical Management

Importance

While congenital malformations and genetic diseases are a leading cause of early infant death, to our knowledge, the contribution of single-gene disorders in this group is undetermined.

Objective

To determine the diagnostic yield and use of clinical exome sequencing in critically ill infants.

Design, Setting, and Participants

Clinical exome sequencing was performed for 278 unrelated infants within the first 100 days of life who were admitted to Texas Children's Hospital in Houston, Texas, during a 5-year period 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 effect on medical management among a group of critically ill infants who were suspected to have genetic disorders.

Results

The mean (SEM) age for infants participating in the study was 28.5 (1.7) days; of these, the mean (SEM) age was 29.0 (2.2) days for infants undergoing proband exome sequencing, 31.5 (3.9) days for trio exome, and 22.7 (3.9) days for critical trio exome. Clinical indications for exome sequencing included a range of medical concerns. Overall, a molecular diagnosis was achieved in 102 infants (36.7%) by clinical exome sequencing, with relatively low yield for cardiovascular abnormalities. The diagnosis affected medical management for 53 infants (52.0%) and had a substantial effect on informed redirection of care, initiation of new subspecialist care, medication/dietary modifications, and furthering life-saving procedures in select patients. Critical trio exome sequencing revealed a molecular diagnosis in 32 of 63 infants (50.8%) at a mean (SEM) of 33.1 (5.6) days of life with a mean (SEM) turnaround time of 13.0 (0.4) days. Clinical care was altered by the diagnosis in 23 of 32 patients (71.9%). The diagnostic yield, patient age at diagnosis, and medical effect in the group that underwent critical trio exome sequencing were significantly different compared with the group who underwent regular exome testing. For deceased infants (n = 81), genetic disorders were molecularly 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 intensive care units and its use has a notable effect on clinical decision making.

Putting the Pieces Together: Clinically Relevant Genetic and Genomic Resources for Hospitalists and Neonatologists

Genetic conditions are individually rare but are common in aggregate, and they often present in the neonatal and early pediatric periods. These conditions are often severe, can be difficult to diagnose and manage, and may heavily affect patients, families, health care systems, and society. Because of recent technological advances, the availability and uptake of genetic and genomic testing are increasing rapidly. However, there is a dearth of trained geneticists and genetic counselors to help guide and explain these conditions and relevant tests. To help hospitalists, neonatologists, and related practitioners navigate this complex and evolving field, we have compiled a list of free (mostly Web-based) resources relevant to the diagnosis and management of genetic conditions and related disorders. These resources, which we describe individually, can be useful for nongeneticist clinicians, and some also include material that can be used to explain concepts and conditions to patients or families. The resources presented are divided into the following categories (which overlap): general information, databases of genetic conditions, resources that can help generate differential diagnoses, databases of genetic testing laboratories (to help with logistics of ordering tests), information on newborn screening, and other resources. We also include a separate list of helpful textbooks and manuals. We conclude with 2 examples describing how some of these resources would be used by a pediatric hospitalist or neonatologist during the inpatient management of a child with a suspected genetic condition.

MIPEP recessive variants cause a syndrome of left ventricular non-compaction, hypotonia, and infantile death

BACKGROUND

Mitochondrial presequence proteases perform fundamental functions as they process about 70 % of all mitochondrial preproteins that are encoded in the nucleus and imported posttranslationally. The mitochondrial intermediate presequence protease MIP/Oct1, which carries out precursor processing, has not yet been established to have a role in human disease.

METHODS

Whole exome sequencing was performed on four unrelated probands with left ventricular non-compaction (LVNC), developmental delay (DD), seizures, and severe hypotonia. Proposed pathogenic variants were confirmed by Sanger sequencing or array comparative genomic hybridization. Functional analysis of the identified MIP variants was performed using the model organism Saccharomyces cerevisiae as the protein and its functions are highly conserved from yeast to human.

RESULTS

Biallelic single nucleotide variants (SNVs) or copy number variants (CNVs) in MIPEP, which encodes MIP, were present in all four probands, three of whom had infantile/childhood death. Two patients had compound heterozygous SNVs (p.L582R/p.L71Q and p.E602*/p.L306F) and one patient from a consanguineous family had a homozygous SNV (p.K343E). The fourth patient, identified through the GeneMatcher tool, a part of the Matchmaker Exchange Project, was found to have inherited a paternal SNV (p.H512D) and a maternal CNV (1.4-Mb deletion of 13q12.12) that includes MIPEP. All amino acids affected in the patients' missense variants are highly conserved from yeast to human and therefore S. cerevisiae was employed for functional analysis (for p.L71Q, p.L306F, and p.K343E). The mutations p.L339F (human p.L306F) and p.K376E (human p.K343E) resulted in a severe decrease of Oct1 protease activity and accumulation of non-processed Oct1 substrates and consequently impaired viability under respiratory growth conditions. The p.L83Q (human p.L71Q) failed to localize to the mitochondria.

CONCLUSIONS

Our findings reveal for the first time the role of the mitochondrial intermediate peptidase in human disease. Loss of MIP function results in a syndrome which consists of LVNC, DD, seizures, hypotonia, and cataracts. Our approach highlights the power of data exchange and the importance of an interrelationship between clinical and research efforts for disease gene discovery.

Whole-genome sequencing for identification of Mendelian disorders in critically ill infants: a retrospective analysis of diagnostic and clinical findings

BACKGROUND

Genetic disorders and congenital anomalies are the leading causes of infant mortality. Diagnosis of most genetic diseases in neonatal and paediatric intensive care units (NICU and PICU) is not sufficiently timely to guide acute clinical management. We used rapid whole-genome sequencing (STATseq) in a level 4 NICU and PICU to assess the rate and types of molecular diagnoses, and the prevalence, types, and effect of diagnoses that are likely to change medical management in critically ill infants.

METHODS

We did a retrospective comparison of STATseq and standard genetic testing in a case series from the NICU and PICU of a large children's hospital between Nov 11, 2011, and Oct 1, 2014. The participants were families with an infant younger than 4 months with an acute illness of suspected genetic cause. The intervention was STATseq of trios (both parents and their affected infant). The main measures were the diagnostic rate, time to diagnosis, and rate of change in management after standard genetic testing and STATseq.

FINDINGS

20 (57%) of 35 infants were diagnosed with a genetic disease by use of STATseq and three (9%) of 32 by use of standard genetic testing (p=0·0002). Median time to genome analysis was 5 days (range 3-153) and median time to STATseq report was 23 days (5-912). 13 (65%) of 20 STATseq diagnoses were associated with de-novo mutations. Acute clinical usefulness was noted in 13 (65%) of 20 infants with a STATseq diagnosis, four (20%) had diagnoses with strongly favourable effects on management, and six (30%) were started on palliative care. 120-day mortality was 57% (12 of 21) in infants with a genetic diagnosis.

INTERPRETATION

In selected acutely ill infants, STATseq had a high rate of diagnosis of genetic disorders. Most diagnoses altered the management of infants in the NICU or PICU. The very high infant mortality rate indicates a substantial need for rapid genomic diagnoses to be allied with a novel framework for precision medicine for infants in NICU and PICU who are diagnosed with genetic diseases to improve outcomes.

FUNDING

Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Human Genome Research Institute, and National Center for Advancing Translational Sciences.

[Results of clinical and genetic diagnosis of rare diseases in the Eastern region of Hungary (2007-2013)]

INTRODUCTION

80% of rare diseases have a genetic origin, and 50% manifest themselves as congenital anomalies. Their adequate health care includes early recognition of genetic anomalies and prevention of recurrence.

AIM

The aims of the authors were to provide correct diagnoses to patients with multiple congenital anomalies with or without mental retardation attending to the outpatient clinic of the Clinical Genetics Center at the University of Debrecen in the time interval between August 1, 2007 and March 31, 2013, establish the possibility of prenatal diagnosis, assess the distribution of different genetic mechanisms in the background of rare genetic diseases, compare them with international data, and develop an algorithm for the diagnostic approach of rare genetic diseases applicable in Hungary.

METHOD

Clinical data and genetic results of patients were evaluated, and patients were categorized into one of the ten proposed etiological groups, based on which the distribution of genetic causes was defined.

RESULTS

Clinical diagnosis was achieved in 64.3% of patients, confirmed genetic diagnosis in 37.8%, while 35.7% of patients remained undiagnosed. Several dysmorphic syndromes and metabolic disorders were first diagnosed in Hungary, two of which unique in the literature.

CONCLUSIONS

In the centre of the authors the diagnostic effectiveness of chromosome aberrations exceeds the international standards, that of known microdeletions and dysmorphic syndromes meets international data, and the genetic diagnosis of mendelian disorders and submicroscopic copy number changes remain below international figures.

Monogenic diseases that can be cured by liver transplantation

While the prevalence of most diseases caused by single-gene mutations is low and defines them as rare conditions, all together, monogenic diseases account for approximately 10 in every 1000 births according to the World Health Organisation. Orthotopic liver transplantation (LT) could offer a therapeutic option in monogenic diseases in two ways: by substituting for an injured liver or by supplying a tissue that can replace a mutant protein. In this respect, LT may be regarded as the correction of a disease at the level of the dysfunctional protein. Monogenic diseases that involve the liver represent a heterogeneous group of disorders. In conditions associated with predominant liver parenchymal damage (i.e., genetic cholestatic disorders, Wilson's disease, hereditary hemochromatosis, tyrosinemia, α1 antitrypsin deficiency), hepatic complications are the major source of morbidity and LT not only replaces a dysfunctional liver but also corrects the genetic defect and effectively cures the disease. A second group includes liver-based genetic disorders characterised by an architecturally near-normal liver (urea cycle disorders, Crigler-Najjar syndrome, familial amyloid polyneuropathy, primary hyperoxaluria type 1, atypical haemolytic uremic syndrome-1). In these defects, extrahepatic complications are the main source of morbidity and mortality while liver function is relatively preserved. Combined transplantation of other organs may be required, and other surgical techniques, such as domino and auxiliary liver transplantation, have been attempted. In a third group of monogenic diseases, the underlying genetic defect is expressed at a systemic level and liver involvement is just one of the clinical manifestations. In these conditions, LT might only be partially curative since the abnormal phenotype is maintained by extrahepatic synthesis of the toxic metabolites (i.e., methylmalonic acidemia, propionic acidemia). This review focuses on principles of diagnosis, management and LT results in both paediatric and adult populations of selected liver-based monogenic diseases, which represent examples of different transplantation strategies, driven by the understanding of the expression of the underlying genetic defect.

High-throughput sequencing and rare genetic diseases

High-throughput sequencing has drastically changed the research of genes responsible for genetic disorders and is now gradually introduced as an additional genetic diagnostic testing in clinical practice. The current debates on the emerging technical, medical and ethical issues as well as the potential optimum use of the available technology are discussed.

Proportion of malformations and genetic disorders among cases encountered at a high-care unit in a children's hospital

Genetic disorders and birth defects account for a high percentage of the admissions in children's hospitals. Congenital malformations and chromosomal abnormalities are the most common causes of infant mortality. So their effects pose serious problems for perinatal health care in Japan, where the infant mortality is very low. This paper describes the reasons for admissions and hospitalization at the high-care unit (HCU) of a major tertiary children's referral center in Japan. We retrospectively reviewed 900 admission charts for the period 2007-2008 and found that genetic disorders and malformations accounted for a significant proportion of the cases requiring admission to the HCU. Further, the rate of recurrent admission was higher for patients with genetic disorders and malformations than for those with acquired, non-genetic conditions. Over the past 30 years, admissions attributed to genetic disorders and malformations has consistently impacted on children's hospital and patients with genetic disorders and malformations form a large part of this facility. These results reflect improvements in medical care for patients with genetic disorders and malformations and further highlight the large proportion of cases with genetic disorders, for which highly specialized management is required. Moreover, this study emphasizes the need for involvement of clinical geneticists in HCUs at children's hospitals.

Birth defects in newborns and stillborns: an example of the Brazilian reality

BACKGROUND

This study constitutes a clinical and genetic study of all newborn and stillborn infants with birth defects seen in a period of one year in a medical school hospital located in Brazil. The aims of this study were to estimate the incidence, causes and consequences of the defects.

METHODS

For all infants we carried out physical assessment, photographic records, analysis of medical records and collection of additional information with the family, besides the karyotypic analysis or molecular tests in indicated cases.

RESULT

The incidence of birth defects was 2.8%. Among them, the etiology was identified in 73.6% (ci95%: 64.4-81.6%). Etiology involving the participation of genetic factors single or associated with environmental factors) was more frequent 94.5%, ci95%: 88.5-98.0%) than those caused exclusively by environmental factors (alcohol in and gestational diabetes mellitus). The conclusive or presumed diagnosis was possible in 85% of the cases. Among them, the isolated congenital heart disease (9.5%) and Down syndrome (9.5%) were the most common, followed by gastroschisis (8.4%), neural tube defects (7.4%) and clubfoot (5.3%). Maternal age, parental consanguinity, exposure to teratogenic agents and family susceptibility were some of the identified risk factors. The most common observed consequences were prolonged hospital stays and death.

CONCLUSIONS

The current incidence of birth defects among newborns and stillbirths of in our population is similar to those obtained by other studies performed in Brazil and in other underdeveloped countries. Birth defects are one of the major causes leading to lost years of potential life. The study of birth defects in underdeveloped countries should continue. The identification of incidence, risk factors and consequences are essential for planning preventive measures and effective treatments.

Frequency of genetic diseases and health coverage of children requiring admission in a general pediatric clinic of northern Greece

BACKGROUND

In order to estimate the causes of pediatric morbidity in our area, with particular emphasis on diseases with a genetic background, we retrospectively categorized the admissions of all children hospitalized in the Department of Pediatrics of the University General Hospital of Alexandroupolis, in the area of Evros, Thrace, Greece over the three year period 2005-2007. Finally, in order to guide health care administrators to improve the delivery of pediatric health care services, we estimated the percentage of hospitalized children who were uninsured and the type of health insurance of those who had medical coverage.

PATIENTS AND METHODS

The causes of admission, as recorded in the medical records were categorized in terms of the major organ and/or system involved and/or the underlying pathology, with emphasis on diseases with a genetic background. Duplicate admissions, i.e., admissions of the same child for the same underlying disease were excluded. Additional information recorded was age, sex, and type of health insurance of all admitted children. Distribution of the causes of admission by study year was compared by chi-square. A p value < 0.05 was considered significant.

RESULTS

Over the study period, there were 4,947 admissions in 2,818 boys and 2,129 girls. Respiratory diseases were the most common accounting for 30%, while infectious diseases followed with 26.4%. The frequency of chromosomal abnormalities among the hospitalized children was only 0.06%. However, if we consider diseases with an underlying genetic background, this percentage rises to 5%. Approximately 10.3% of the admitted children had no health insurance.

CONCLUSIONS

The percentage of children hospitalized in our area due to a disease with an underlying genetic background was 5%. This percentage pertains to a Department of Pediatrics that has no inpatient subspecialty units and which is located within a General hospital, because hospitalizations for genetic diseases are more frequent in specialized pediatric hospitals, with competence in clinical genetics. The double figure of uninsured children is worrisome and dictates the need for governmental efforts for universal pediatric health coverage in our country.

Racial differences in infant mortality attributable to birth defects in the United States, 1989-2002

BACKGROUND

The objective is to study racial differences in infant mortality attributable to birth defects (IMBD) in the United States.

METHODS

We analyzed 1989-1991 and 1995-2002 linked birth/death files for trends and racial differences in IMBD by selected categories of birth defects for infants of non-Hispanic white, non-Hispanic black, and Hispanic mothers.

RESULTS

In 1989-2002, the IMBD rates declined. However, the decline in postneonatal mortality attributable to birth defects (PMBD) rate was significantly slower than that of overall postneonatal mortality. The adjusted rate ratio for non-Hispanic black and Hispanic versus non-Hispanic white for neonatal mortality attributable to birth defects (NMBD) remained unchanged from 1989-1991 through 2000-2002. For PMBD, it increased from 0.97 (95% confidence interval [CI], 0.90-1.13) in 1989-1991 to 1.12 (95% CI, 1.04-1.21) in 2001-2002 and from 1.08 (95% CI, 1.00-1.16) to 1.18 (95% CI, 1.10-1.27) for non-Hispanic black and Hispanic, respectively. Infant mortality due to cardiovascular and central nervous system defects were the main contributors to the increased racial disparities in PMBD rates.

CONCLUSIONS

The disparity in PMBD between infants of non-Hispanic black and Hispanic mothers and infants of non-Hispanic white mothers increased significantly from 1989-1991 to 2000-2002. Further studies are needed to assess the extent to which delays in care or lack of access to care for infants with birth defects might be contributing to the disparity in IMBD.

A population-based study of birth defects in Malaysia

Birth defects are one of the leading causes of paediatric disability and mortality in developed and developing countries. Data on birth defects from population-based studies originating from developing countries are lacking. One of the objectives of this study was to determine the epidemiology of major birth defects in births during the perinatal period in Kinta district, Perak, Malaysia over a 14-month period, using a population-based birth defect register. There were 253 babies with major birth defects in 17,720 births, giving an incidence of 14.3/1000 births, a birth prevalence of 1 in 70. There were 80 babies with multiple birth defects and 173 with isolated birth defects. The exact syndromic diagnosis of the babies with multiple birth defects could not be identified in 18 (22.5%) babies. The main organ systems involved in the isolated birth defects were cardiovascular (13.8%), cleft lip and palate (11.9%), clubfeet (9.1%), central nervous system (CNS) (including neural tube defects) (7.9%), musculoskeletal (5.5%) and gastrointestinal systems (4.7%), and hydrops fetalis (4.3%). The babies with major birth defects were associated with lower birth weights, premature deliveries, higher Caesarean section rates, prolonged hospitalization and increased specialist care. Among the cohort of babies with major birth defects, the mortality rate was 25.2% during the perinatal period. Mothers with affected babies were associated with advanced maternal age, birth defects themselves or their relatives but not in their other offspring, and significantly higher rates of previous abortions. The consanguinity rate of 2.4% was twice that of the control population. It is concluded that a birth defects register is needed to monitor these developments and future interventional trials are needed to reduce birth defects in Malaysia.