Diagnostic Utility of Whole Genome Sequencing After Negative Karyotyping/Chromosomal Microarray in Infants Born With Multiple Congenital Anomalies.

BACKGROUND: Achieving a definitive genetic diagnosis of unexplained multiple congenital anomalies (MCAs) in neonatal intensive care units (NICUs) infants is challenging because of the limited diagnostic capabilities of conventional genetic tests. Although the implementation of whole genome sequencing (WGS) has commenced for diagnosing MCAs, due to constraints in resources and faculty, many NICUs continue to utilize chromosomal microarray (CMA) and/or karyotyping as the initial diagnostic approach. We aimed to evaluate the diagnostic efficacy of WGS in infants with MCAs who have received negative results from karyotyping and/or CMA. METHODS: In this prospective study, we enrolled 80 infants with MCAs who were admitted to a NICU at a single center and had received negative results from CMA and/or karyotyping. The phenotypic characteristics were classified according to the International Classification of Diseases and the Human Phenotype Ontology. We assessed the diagnostic yield of trio-WGS in infants with normal chromosomal result and explored the process of diagnosing by analyzing both phenotype and genotype. Also, we compared the phenotype and clinical outcomes between the groups diagnosed with WGS and the undiagnosed group. RESULTS: The diagnostic yield of WGS was 26% (21/80), of which 76% were novel variants. There was a higher diagnostic yield in cases of craniofacial abnormalities, including those of the eye and ear, and a lower diagnostic yield in cases of gastrointestinal and genitourinary abnormalities. In addition, higher rates of rehabilitation therapy and gastrostomy were observed in WGS-diagnosed infants than in undiagnosed infants. CONCLUSION: This prospective cohort study assessed the usefulness of trio-WGS following chromosomal analysis for diagnosing MCAs in the NICU and revealed improvements in the diagnostic yield and clinical utility of WGS.

Mortality and Morbidities according to Time of Birth in Extremely Low Birth Weight Infants.

BACKGROUND: Although the overall quality of high-risk neonatal care has improved recently, there is still concern about a difference in the quality of care when comparing off-hour births and regular-hour births. Moreover, there are no data in Korea regarding the impact of time of birth on mortality and morbidities in preterm infants. METHODS: A total of 3,220 infants weighing < 1,000 g and born at 23-34 weeks in 2013-2017 were analyzed based on the Korean Neonatal Network data. Mortality and major morbidities were analyzed using logistic regression according to time of birth during off-hours (nighttime, weekend, and holiday) and regular hours. The institutes were sub-grouped into hospital group I and hospital group II based on the neonatal intensive care unit (NICU) care level defined by the mortality rates of < 50% and ≥ 50%, respectively, in infants born at 23-24 weeks' gestation. RESULTS: The number of births during regular hours and off-hours was similar. In the total population and hospital group I, off-hour births were not associated with increased neonatal mortality and morbidities. However, in hospital group II, increased early mortality was found in the off-hour births when compared to regular-hour births. CONCLUSION: Efforts to improve the overall quality of NICU are required to lower the early mortality rate in off-hour births. Also, other sensitive indexes for the evaluation of quality of NICU care should be further studied.

Epidemiology of Macrosomia in Korea: Growth and Development.

BACKGROUND: Macrosomia, as an infant with birth weight over 4 kg, can have several perinatal, and neonatal complications. This study aimed to estimate the incidence of macrosomia in Korea and to identify the growth and developmental outcomes and other neonatal complications. METHODS: In total, 397,203 infants who were born in 2013 with birth weight ≥ 2.5 kg and who underwent infant health check-up between their 1st and 7th visit were included from the National Health Insurance Service database. The information was obtained by the International Classification of Diseases-10 codes or self-reported questionnaires in the National Health Screening Program. RESULTS: The distribution of infants by birth weight was as follows: 384,181 (97%) infants in the 2.5-3.99 kg (reference) group, 12,016 (3%) infants in the 4.0-4.49 kg group, 772 (0.2%) infants in the 4.5-4.99 kg group, and 78 (0.02%) infants in the ≥ 5 kg group. Macrosomia showed significantly higher incidence of sepsis, male sex, and mothers with GDM and birth injury. There was a significant difference in weight, height, and head circumference according to age, birth weight group, and combination of age and birth weight, respectively (P < 0.001). The number of infants with the weight above the 90th percentile in macrosomia at each health check-up showed higher incidence than in reference group. The mean body mass index significantly differed among the groups, as 50.6 in infants with 2.5-3.99 kg of birth weight, 63.5 with 4.0-4.49 kg, 71.0 with 4.5-4.99 kg, and 73.1 with ≥ 5 kg. There was a significant difference in the incidence of poor developmental results between infants with macrosomia and the reference group at 24, 36 and 48 month of age. CONCLUSION: Macrosomia was significantly associated with the risk of sepsis, birth injury, obesity and developmental problem especially in a boy born from mothers with gestational diabetes mellitus. Careful monitoring and proper strategies for monitoring growth and development are needed.

Recent Changes in the Incidence of Bronchopulmonary Dysplasia among Very-Low-Birth-Weight Infants in Korea.

We investigated the incidence of bronchopulmonary dysplasia (BPD) in very-low-birth-weight (VLBW) infants in Korea using the Korean Neonatal Network (KNN) data. In total, 2,386 VLBW infants born from January 2013 to June 2014 were prospectively registered. BPD was defined as supplemental oxygen or positive pressure support at 36 weeks postmenstrual age (PMA). The overall incidence of BPD was 28.9%, and the overall mortality rate in the neonatal intensive care units (NICUs) was 11.9%. To investigate recent changes in the incidence of BPD among VLBW infants, we compared the BPD rate in the present study with the latest nationwide retrospective survey conducted between 2007 and 2008. For comparison, we selected infants (23-31 weeks of gestation) (n=1,990) to adjust for the same conditions with the previous survey in 2007-2008 (n=3,841). Among the limited data on VLBW infants (23-31 weeks of gestation), the incidence of BPD increased by 85% (from 17.8% to 33.0%) and the mortality rate in the NICU decreased by 31.4% (from 18.8% to 12.9%) compared to those in the study conducted in 2007-2008. The current trend of increase in the incidence of BPD among infants can be attributed to the increase in the survival rate of VLBW infants.

Double exposure to intra-amniotic lipopolysaccharide and maternal betamethasone induces sustained increase of neutrophils in the lungs and disrupts alveolarization in newborn rats.

AIM: We investigated the combined effects of intra-amniotic lipopolysaccharide (LPS) and maternal betamethasone (BMZ) on alveolarization using a newborn rat model. METHODS: LPS (1.0 µg/sac) or vehicle was injected into the amniotic sacs of pregnant rats and BMZ (170 µg/kg) or vehicle was injected intramuscularly into the pregnant rats twice at 8-h intervals on gestation day 20. The rat pups were delivered spontaneously after 2-2.5 days and raised until the measurements were taken. Bronchoalveolar lavage was performed on days 2 and 5, and morphometric analyses of the lungs were performed on days 5 and 14. RESULTS: Intra-amniotic LPS significantly increased the neutrophils in the bronchoalveolar lavage fluid (BALF) on day 2, but double exposure to LPS and BMZ significantly alleviated the neutrophil increase in the BALF. On day 5, while the neutrophils in the BALF decreased in the animals exposed to LPS alone, the neutrophil numbers in the BALF were steady in the animals exposed to both LPS and BMZ. Morphometric analyses on days 5 and 14 revealed a significant disruption of alveolarization only in the animals exposed to both LPS and BMZ. CONCLUSIONS: Our results suggested that double exposure to maternal BMZ and intra-amniotic LPS induces sustained increase of neutrophils in the lungs and disrupts alveolarization.

Required biological time for lung maturation and duration of invasive ventilation: a Korean cohort study of very low birth weight infants.

Background: We investigated the duration of invasive ventilation among very low birth weight (VLBW) infants to evaluate the current minimum time required for lung maturation to breathe without ventilator assistance after preterm birth. Methods: A total of 14,658 VLBW infants born at ≤32+6 weeks between 2013 and 2020 were enrolled. Clinical data were collected from the Korean Neonatal Network, a national prospective cohort registry of VLBW infants from 70 neonatal intensive care units. Differences in the duration of invasive ventilation according to gestational age and birth weight were investigated. Recent trends and changes in assisted ventilation duration and associated perinatal factors between 2017-20 and 2013-16 were compared. Risk factors related to the duration of assisted ventilation were also identified. Results: The overall duration of invasive ventilation was 16.3 days and the estimated minimum time required corresponded to 30+4 weeks of gestation. The median duration of invasive ventilation was 28.0, 13.0, 3.0, and 1.0 days at <26, 26-27, 28-29, and 30-32 weeks of gestation, respectively. In each gestational age group, the estimated minimum weaning points from the assisted ventilator were 29+5, 30+2, 30+2, and 31+5 weeks of gestation. The duration of non-invasive ventilation (17.9 vs. 22.5 days) and the incidence of bronchopulmonary dysplasia (28.1% vs. 31.9%) increased in 2017-20 (n = 7,221) than in 2013-16 (n = 7,437). In contrast, the duration of invasive ventilation and overall survival rate did not change during the periods 2017-20 and 2013-16. Surfactant treatment and air leaks were associated with increased duration of invasive ventilation (inverse hazard ratio 1.50, 95% CI, 1.04-2.15; inverse hazard ratio 1.62, 95% CI, 1.29-2.04). We expressed the incidence proportion of ventilator weaning according to the invasive ventilation duration using Kaplan-Meier survival curves. The slope of the curve slowly decreased as gestational age and birth weight were low and risk factors were present. Conclusions: This population-based data on invasive ventilation duration among VLBW infants suggest the present limitation of postnatal lung maturation under specific perinatal conditions after preterm birth. Furthermore, this study provides detailed references for designing and/or assessing earlier ventilator weaning protocols and lung protection strategies by comparing populations or neonatal networks.

Comparative effectiveness of explainable machine learning approaches for extrauterine growth restriction classification in preterm infants using longitudinal data.

Introduction: Preterm birth is a leading cause of infant mortality and morbidity. Despite the improvement in the overall mortality in premature infants, the intact survival of these infants remains a significant challenge. Screening the physical growth of infants is fundamental to potentially reducing the escalation of this disorder. Recently, machine learning models have been used to predict the growth restrictions of infants; however, they frequently rely on conventional risk factors and cross-sectional data and do not leverage the longitudinal database associated with medical data from laboratory tests. Methods: This study aimed to present an automated interpretable ML-based approach for the prediction and classification of short-term growth outcomes in preterm infants. We prepared four datasets based on weight and length including weight baseline, length baseline, weight follow-up, and length follow-up. The CHA Bundang Medical Center Neonatal Intensive Care Unit dataset was classified using two well-known supervised machine learning algorithms, namely support vector machine (SVM) and logistic regression (LR). A five-fold cross-validation, and several performance measures, including accuracy, precision, recall and F1-score were used to compare classifier performances. We further illustrated the models' trustworthiness using calibration and cumulative curves. The visualized global interpretations using Shapley additive explanation (SHAP) is provided for analyzing variables' contribution to final prediction. Results: Based on the experimental results with area under the curve, the discrimination ability of the SVM algorithm was found to better than that of the LR model on three of the four datasets with 81%, 76% and 72% in weight follow-up, length baseline and length follow-up dataset respectively. The LR classifier achieved a better ROC score only on the weight baseline dataset with 83%. The global interpretability results revealed that pregnancy-induced hypertension, gestational age, twin birth, birth weight, antenatal corticosteroid use, premature rupture of membranes, sex, and birth length were consistently ranked as important variables in both the baseline and follow-up datasets. Discussion: The application of machine learning models to the early detection and automated classification of short-term growth outcomes in preterm infants achieved high accuracy and may provide an efficient framework for clinical decision systems enabling more effective monitoring and facilitating timely intervention.

Optimal Protocols and Management of Clinical and Genomic Data Collection to Assist in the Early Diagnosis and Treatment of Multiple Congenital Anomalies.

Standardized protocols have been designed and developed specifically for clinical information collection and obtaining trio genomic information from infants affected with congenital anomalies (CA) and their parents, as well as securing human biological resources. The protocols include clinical and genomic information collection on multiple CA that were difficult to diagnose using pre-existing screening methods. We obtained human-derived resources and genomic information from 138 cases, including 45 families of infants with CA and their parent trios. For the clinical information collection protocol, criteria for target patient selection and a consent system for collecting and utilizing research resources are crucial. Whole genome sequencing data were generated for all participants, and standardized protocols were developed for resource collection and manufacturing. We recorded the phenotype information according to the Human Phenotype Ontology term, and epidemiological information was collected through an environmental factor questionnaire. Updating and recording of clinical symptoms and genetic information that have been newly added or changed over time are significant. The protocols enabled long-term tracking by including the growth and development status that reflect the important characteristics of newborns. Using these clinical and genetic information collection protocols for CA, an essential platform for early genetic diagnosis and diagnostic research can be established, and new genetic diagnostic guidelines can be presented in the near future.

Prognostic factors for treatment outcomes in transient tachypnea of the newborn.

BACKGROUND: Transient tachypnea of the newborn (TTN) is a clinical syndrome associated with respiratory distress usually seen shortly after delivery in infants. This study aims to determine the risk factors predicting treatment outcomes in infants with TTN. METHODS: Data from 236 infants diagnosed with TTN during the study period were evaluated retrospectively. Logistic regression analyses were performed to select significant risk factor for prognosis (prolonged oxygen therapy, application of mechanical ventilator, and prolonged hospital stay) of TTN among components of clinical variables. RESULTS: Of the 236 TTN infants, 111 (47.0%) infants were delivered via cesarean section (CS) without labor, 29 (12.3%) infants were delivered via CS with labor, and 96 (40.7%) were delivered via vaginal birth. Lower Apgar score at 1 min (OR: 3.03; 95%CI: 1.25-7.36) and lower umbilical artery pH (OR: 4.00; 95%CI 1.55-10.49) were associated with a significantly increased risk for mechanical ventilator care. Also, late-preterm delivery (OR: 4.70; 95%CI: 2.11-10.49) was independently associated with risk of prolonged duration of hospital stay. CONCLUSIONS: Late-preterm delivery, lower initial umbilical artery pH (<7.25), and lower Apgar score at 1 min were independently associated with poor prognostic treatment outcomes in infants with TTN.

A Preterm Infant with Feeding Aspiration Diagnosed with BOR Syndrome, Confirmed Case by Whole-Genome Sequencing and Structural Variant Calling.

Branchiootorenal (BOR) syndrome is a rare autosomal dominant inherited disease with a prevalence of approximately 1 in 40,000 newborns. This disease is characterized by hearing loss, preauricular pits, branchial fistulas or cysts, and renal dysplasia. We discovered a case of BOR syndrome in a premature 2-week-old female infant with a gestational age of 32 weeks and two days. She and her family had major symptoms and a family history of BOR. BOR syndrome was confirmed by whole-genome sequencing and structural variant calling, which revealed an EYA1 exon 5-6 deletion. The infant had recurrent sleep and feeding cyanosis with second branchial anomalies. Via videofluoroscopic swallowing study and a modified barium swallow test, penetration into the vocal cords was observed before and during swallowing when bottle feeding. This is the first report of a preterm infant early diagnosed with BOR syndrome in which deletion margin was accurately identified by whole-genome sequencing and structural variant calling in Republic of Korea.

Conservative Management of Patent Ductus Arteriosus Is Feasible in the Peri-Viable Infants at 22-25 Gestational Weeks.

The purpose of this study was to determine the natural course of hemodynamically significant (HS) patent ductus arteriosus (PDA) with conservative management and whether the presence or prolonged duration of HS PDA affected mortality/morbidities in infants at 22-25 weeks estimated gestational age (EGA). We retrospectively reviewed the medical records of 77 infants born at 22-25 weeks EGA, stratified into 22-23 weeks (n = 21) and 24-25 weeks EGA (n = 56). HS PDA was present in 77%, 76%, and 77%, and open ductus at discharge was 12%, 13%, and 12% in the total and at 22-23 and 24-25 weeks EGA infants, respectively. For backup rescue treatment, 7% and 5% of the infants received oral ibuprofen and device closure, respectively. A mortality rate of 9% was found in the HS PDA (+) infants, significantly lower than the 28% in HS PDA (-) infants. There are no significant differences in morbidities. In multivariate analyses, the presence and/or prolonged duration of HS PDA was not associated with increased mortality or morbidity. Spontaneous closure of HS PDA was achieved through conservative management in the peri-viable infants at 22-25 weeks EGA.

Conservative Non-intervention Approach for Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants.

While persistent patent ductus arteriosus (PDA) in preterm infants has been known to be associated with increased mortality and morbidities including bronchopulmonary dysplasia, and necrotizing enterocolitis, there is minimal evidence supporting their causal relationships, and most traditional medical and/or surgical treatments have failed to show improvements in these outcomes. As such, the pendulum has swung toward the conservative non-intervention approach for the management of persistent PDA during the last decade; however, the benefits and risks of this approach are unclear. In this mini review, we focused on whom, when, and how to apply the conservative non-intervention approach for persistent PDA, especially in extremely preterm infants.

Sleep-wake cycle on amplitude-integrated EEG and neuroimage outcomes in newborns.

BACKGROUND: The aim of this study was to evaluate the results of sleep-wake cycle monitoring using amplitude-integrated EEG (aEEG) and neuroimaging in newborn infants with a possible perinatal hypoxic insult, investigate the correlation between the findings, and determine the relevance of the findings to reasonably predict neurological outcome. METHODS: aEEG was recorded among newborn infants suspected of perinatal asphyxia between November, 2014 and June, 2015 in one neonatal intensive care unit facility. Brain imaging with serial ultrasonography and MRI when available were performed, and the infants were divided into two groups according to findings and potential neurological outcome: Group I (favorable findings) and Group II (severe findings such as high grade intraventricular hemorrhage, cerebral infarction or white matter injury). Established sleep-wake cycle times after birth was compared between the two groups. RESULTS: Among 107 newborn infants, 85 subjects were classified as Group I and the remaining 22 subjects as Group II. The total number of aEEG sessions was 207 and recording time was 2,796 h with a mean of 14.43 ± 13.40 h per study. Estimated times of cyclicity were earlier in Group I (113.34 h, 95 % CI 82.31-144.37) as compared to Group II (504.39 h, 95 % CI 319.91-688.88; p < 0.001). CONCLUSIONS: Delayed cyclicity on aEEG has a strong correlation with unfavorable brain neuroimages in newborns with possible perinatal asphyxia. If sleep-wake cycles do not appear during initial period after birth, follow-up aEEG studies are recommended. TRIAL REGISTRATION: Retrospectively registered Registration number: BD 2015-148 Name of registry: amplitude integrated EEG in neonate Date of registration: September 9, 2015.

Neonatal vitelline vein aneurysm with thrombosis: prompt treatment should be needed.

Vitelline veins are a pair of embryonic structures. The veins develop the portal vein system. Serious problems occur if the vitelline vein does not regress and becomes an aneurysm. Thrombus formation in the vitelline vein aneurysm could lead to portal vein thrombosis and portal hypertension unless promptly and correctly treated. Though vitelline vein aneurysm is an extremely rare anomaly, it rapidly progresses to portal vein thrombosis that requires prompt diagnosis and treatment. We reported a case of neonatal vitelline vein aneurysm and thrombosis that was cured by prompt operation.

Genetic risk factors associated with respiratory distress syndrome.

Respiratory distress syndrome (RDS) among preterm infants is typically due to a quantitative deficiency of pulmonary surfactant. Aside from the degree of prematurity, diverse environmental and genetic factors can affect the development of RDS. The variance of the risk of RDS in various races/ethnicities or monozygotic/dizygotic twins has suggested genetic influences on this disorder. So far, several specific mutations in genes encoding surfactant-associated molecules have confirmed this. Specific genetic variants contributing to the regulation of pulmonary development, its structure and function, or the inflammatory response could be candidate risk factors for the development of RDS. This review summarizes the background that suggests the genetic predisposition of RDS, the identified mutations, and candidate genetic polymorphisms of pulmonary surfactant proteins associated with RDS.

Surfactant protein A associated with respiratory distress syndrome in Korean preterm infants: evidence of ethnic difference.

BACKGROUND: Insufficiency of the pulmonary surfactant system is the primary cause of respiratory distress syndrome (RDS) in preterm infants. Genetic factors, including specific single-nucleotide polymorphisms in the genetic components of surfactant protein A (SP-A1 and SP-A2), affect protein structure and function, as well as risk of RDS. OBJECTIVE: We investigated the association between variations in SP-A genotypes and RDS within the genetically homogeneous Korean population. METHODS: We used TaqMan® real-time polymerase chain reaction technology to assess nine single-nucleotide polymorphisms of SP-A in 261 full-term and 152 preterm infants. Among the preterm infants, 76 infants with RDS were matched with 76 control infants with respect to gestation, use of antenatal steroids and gender. RESULTS: The SP-A2 1A(0) variant and the homozygous 1A(0)/1A(0) genotype were associated with protection from RDS (OR 0.31, 95% CI 0.13-0.78). In addition, the 1A(1) carrier genotype (containing one copy of the 1A(1) variant) was associated with increased risk of RDS (OR 2.42, 95% CI 1.06-5.52). The significance of these results is that the association of patterns with RDS was opposite to the findings of previous research with Finnish and North American study populations. CONCLUSIONS: We have identified associations between specific variants of the SP-A genes and RDS risk in the Korean preterm study population. Our data strongly support SP-A as a candidate gene for susceptibility to RDS, and reveal the dissimilarity of the associated risk/protective genetic variants between different ethnic study populations.

22q11.2 Microduplication with thyroid hemiagenesis.

BACKGROUND: Chromosome 22q11.2 microduplications are extremely rarely detected; in comparison, the deletion of same region, known as the DiGeorge/velocardiofacial syndrome, occurs more frequently. Thyroid anomalies commonly occur in patients with 22q11.2 deletion syndrome, however few reports of thyroid anomalies associated with 22q11.2 microduplication have been published thus far. CASE REPORT: We present a case of a male infant who was prenatally diagnosed with 22q11.2 microduplication and was found to have congenital hypothyroidism due to thyroid hemiagenesis after birth. Moreover, the baby had bilateral hearing impairment, bilateral cryptorchidism, and a rotated penis. At the age of 2 years, the infant was euthyroid with levothyroxine replacement, but he showed significant developmental delay. CONCLUSIONS: To our knowledge, this is the first case of congenital hypothyroidism with thyroid hemiagenesis in a patient showing 22q11.2 microduplication. Thyroid dysgenesis could be an additional clinical feature shared by the 22q11.2 microduplication and deletion syndrome, suggesting that the duplication and deletion of a gene may result in a common phenotype. Thyroid dysgenesis should be considered in the evaluation and management of patients with this genomic disorder.