Cyanoacrylate glue as part of a new bundle to decrease neonatal PICC-related complications.

A "bundle" is defined as a combination of evidence-based interventions that, if followed collectively and reliably, improve patient outcomes. The aim of this quasi-experimental study, conducted in a level-III NICU in Belgium, was to assess the impact of central line dressing and maintenance bundle implementation on the rate of catheter-related mechanical complications. We performed a quality improvement (QI) project. Prior to bundle implementation, neonatal PICC lines were secured by Steri-Strip® and occlusive dressing. We implemented a new PICC bundle consisting of the use of glue, sutureless device (Griplock®), and a transparent dressing to secure the catheter to the skin. We compared the rate of infections, mechanical complications, and dislocations before and after bundle implementation (periods 1 and 2, respectively). The use of glue resulted in a significantly decreased rate of central line-associated bloodstream infection (CLABSI) (p < 0.001), dislocations, and mechanical complications (p < 0.0001). During period 2, there was a significant increase for the average number of days the catheter stayed in place (p < 0.05). We did not observe catheter breakage or patient skin irritations attributable to the use of glue (not even in ELBW infants). CONCLUSION: The implementation of the new bundle to secure neonatal PICCs in our NICU was associated with a significant reduction in CLABSI and dislodgment rates, without glue-related complications. Active surveillance of CVC placement procedure, positioning, and management, as well as analysis of related complications is crucial for improving patient safety. Continuous implementation of up-to-date central line bundles based on best practice recommendations is a key for quality improvement in NICUs. WHAT IS KNOWN: • Stable vascular access is crucial in the NICU. Neonatal PICC securement issues can have serious consequences and are associated with device failure. WHAT IS NEW: • Catheter securement with tissue adhesive is safe and effective in reducing failure and complication rates in the neonatal population.

Implementing intact cord resuscitation in very preterm infants: feasibility and pitfalls.

The purpose of this study is to evaluate the feasibility of intact cord resuscitation (ICR) in very preterm infants using a custom-equipped mobile resuscitation trolley (LifeStart®). We collected maternal and neonatal data of all inborn infants < 32 weeks eligible for ICR per our protocol over 9 months from ICR implementation. We compared rates of ICR between the beginning and the end of the study period. We reviewed maternal and neonatal adverse events related to the procedure and direct outcomes. In order to assess potential quality improvements related to the procedure, we collected the same data in the infants born in the 9-month period preceding ICR implementation. Out of 44 infants born < 32 weeks during the period, 27 were eligible for ICR. Failure to initiate ICR occurred in 9/27, exclusively in the first 5.5 months of the study. In one infant, ICR was interrupted prior to 2 min due to placental abruption. No ICR procedure had to be interrupted due to insufficient cord length. Among the 18 infants who completed ICR, cord clamping timing increased significantly over the study period, from 3.0 [2.5-3.5] to 4.2 min [3.1-8.3] (p = 0.02). No significant maternal blood loss or wound complications were noted. No infant deaths were attributable to failure or direct consequence of ICR, and no infant experienced hypoxic respiratory failure (intubation, FiO2 ≥ 0.4), asphyxia (pH < 7.2), or blood pressure instability (< 2 SD) following stabilization. Hemoglobin level after cord clamping was higher in the ICR cohort than in the pre-implementation group. Seven out of 18 infants exposed to ICR had a temperature < 36.5 °C on admission.   Conclusion: ICR is feasible in very preterm infants. Temperature management requires special attention. Multidisciplinary simulation training before implementation and systematic post-implementation quality improvement meetings may significantly increase ICR program success. What is Known: • Because infants born < 32 weeks often require cardiorespiratory resuscitation at birth, they are not offered delayed cord clamping in the majority of neonatal intensive care units. • Recently, fully equipped mobile trolleys have been developed in order to allow bedside resuscitation with an intact cord. What is New: • Variable timing of cord clamping based on the infant's transition and respiratory stability, i.e., "physiology-based cord clamping," is safely achievable in very preterm infants. • Intact cord resuscitation requires specific equipment, operational protocols, and a high level of preparation from both obstetrical and neonatal teams, with a learning curve that can be streamlined by multidisciplinary simulation training.

First Genotype-Phenotype Study in TBX4 Syndrome: Gain-of-Function Mutations Causative for Lung Disease.

Rationale: Despite the increased recognition of TBX4 (T-BOX transcription factor 4)-associated pulmonary arterial hypertension (PAH), genotype-phenotype associations are lacking and may provide important insights. Objectives: To compile and functionally characterize all TBX4 variants reported to date and undertake a comprehensive genotype-phenotype analysis. Methods: We assembled a multicenter cohort of 137 patients harboring monoallelic TBX4 variants and assessed the pathogenicity of missense variation (n = 42) using a novel luciferase reporter assay containing T-BOX binding motifs. We sought genotype-phenotype correlations and undertook a comparative analysis with patients with PAH with BMPR2 (Bone Morphogenetic Protein Receptor type 2) causal variants (n = 162) or no identified variants in PAH-associated genes (n = 741) genotyped via the National Institute for Health Research BioResource-Rare Diseases. Measurements and Main Results: Functional assessment of TBX4 missense variants led to the novel finding of gain-of-function effects associated with older age at diagnosis of lung disease compared with loss-of-function effects (P = 0.038). Variants located in the T-BOX and nuclear localization domains were associated with earlier presentation (P = 0.005) and increased incidence of interstitial lung disease (P = 0.003). Event-free survival (death or transplantation) was shorter in the T-BOX group (P = 0.022), although age had a significant effect in the hazard model (P = 0.0461). Carriers of TBX4 variants were diagnosed at a younger age (P < 0.001) and had worse baseline lung function (FEV1, FVC) (P = 0.009) than the BMPR2 and no identified causal variant groups. Conclusions: We demonstrated that TBX4 syndrome is not strictly the result of haploinsufficiency but can also be caused by gain of function. The pleiotropic effects of TBX4 in lung disease may be in part explained by the differential effect of pathogenic mutations located in critical protein domains.

Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2.

Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.

Bronchopulmonary dysplasia and wnt pathway-associated single nucleotide polymorphisms.

AIM: Genetic variants contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to evaluate the association of 45 SNPs with BPD susceptibility in a Turkish premature infant cohort. METHODS: Infants with gestational age <32 weeks were included. Patients were divided into BPD or no-BPD groups according to oxygen need at 28 days of life, and stratified according to the severity of BPD. We genotyped 45 SNPs, previously identified as BPD risk factors, in 192 infants. RESULTS: A total of eight SNPs were associated with BPD risk at allele level, two of which (rs4883955 on KLF12 and rs9953270 on CHST9) were also associated at the genotype level. Functional relationship maps suggested an interaction between five of these genes, converging on WNT5A, a member of the WNT pathway known to be implicated in BPD pathogenesis. Dysfunctional CHST9 and KLF12 variants may contribute to BPD pathogenesis through an interaction with WNT5A. CONCLUSIONS: We suggest investigating the role of SNPs on different genes which are in relation with the Wnt pathway in BPD pathogenesis. We identified eight SNPs as risk factors for BPD in this study. In-silico functional maps show an interaction of the genes harboring these SNPs with the WNT pathway, supporting its role in BPD pathogenesis. TRIAL REGISTRATION: NCT03467828. IMPACT: It is known that genetic factors may contribute to the development of BPD in preterm infants. Further studies are required to identify specific genes that play a role in the BPD pathway to evaluate them as a target for therapeutic interventions. Our study shows an association of BPD predisposition with certain polymorphisms on MBL2, NFKBIA, CEP170, MAGI2, and VEGFA genes at allele level and polymorphisms on CHST9 and KLF12 genes at both allele and genotype level. In-silico functional mapping shows a functional relationship of these five genes with WNT5A, suggesting that Wnt pathway disruption may play a role in BPD pathogenesis.

Early diagnosis and targeted approaches to pulmonary vascular disease in bronchopulmonary dysplasia.

Pulmonary hypertension has emerged as a life-threatening disease in preterm infants suffering from bronchopulmonary dysplasia (BPD). Its development is closely linked to respiratory disease, as vasculogenesis and alveologenesis are closely interconnected. Once clinically significant, BPD-associated pulmonary hypertension (BPD-PH) can be challenging to manage, due to poor reversibility and multiple comorbidities frequently associated. The pulmonary vascular disease process underlying BPD-PH is the result of multiple innate and acquired factors, and emerging evidence suggests that it progressively develops since birth and, in certain instances, may begin as early as fetal life. Therefore, early recognition and intervention are of great importance in order to improve long-term outcomes. Based on the most recent knowledge of BPD-PH pathophysiology, we review state-of-the-art screening and diagnostic imaging techniques currently available, their utility for clinicians, and their applicability and limitations in this specific population. We also discuss some biochemical markers studied in humans as a possible complement to imaging for the detection of pulmonary vascular disease at its early stages and the monitoring of its progression. In the second part, we review pharmacological agents currently available for BPD-PH treatment or under preclinical investigation, and discuss their applicability, as well as possible approaches for early-stage interventions in fetuses and neonates. IMPACT: BPD-associated PH is a complex disease involving genetic and epigenetic factors, as well as environmental exposures starting from fetal life. The value of combining multiple imaging and biochemical biomarkers is emerging, but requires larger, multicenter studies for validation and diffusion. Since "single-bullet" approaches have proven elusive so far, combined pharmacological regimen and cell-based therapies may represent important avenues for research leading to future cure and prevention.

How to minimize central line-associated bloodstream infections in a neonatal intensive care unit: a quality improvement intervention based on a retrospective analysis and the adoption of an evidence-based bundle.

Central line-associated bloodstream infection (CLABSI) is a significant cause of morbidity and mortality in neonatal intensive care units (NICUs). A "bundle" is defined as a combination of evidence-based interventions that provided they are followed collectively and reliably, are proven to improve patient outcomes. The aim of this quasi-experimental study was to assess the impact of new central line insertion, dressing, and maintenance "bundles" on the rate of CLABSI and catheter-related complications. We performed a quality improvement (QI), prospective, before-after study. In the first 9-month period, the old "bundles" and pre-existing materials were used/applied. An intervention period then occurred with changes made to materials used and the implementation of new "bundles" related to various aspects of central lines care. A second 6-month period was then assessed and the CLABSI rates were measured in the NICU pre- and post-intervention period. The QI measures were the rate of CLABSI and catheter-related complications. Data are still being collected after the study to verify sustainability. The implementation of the new "bundles" and the change of certain materials resulted in a significantly decreased rate of CLABSI (8.4 to 1.8 infections per 1000 central venous catheter (CVC) days, p = 0.02,) as well as decreased catheter-related complications (47 to 10, p < 0.007).Conclusions: The analysis of pre-existing "bundles" and the implementation of updated central line "bundles" based on best practice recommendations are crucial for reducing the rate of CLABSI in the NICU. The implementation of the new evidence-based central line "bundles" was associated with a significant reduction in CLABSI rate in our unit soon after implementation. What is Known: • Central line-associated bloodstream infection (CLABSI) is a major cause of morbidity and mortality in the neonatal population. • The implementation of evidence-based "bundles" in the NICU is associated with a reduction in the incidence of CLABSI. What is New: • For the improvement in quality care in the NICU, audits are necessary to assess the existing systems. • The "Plan-Do-Study-Act cycle" is an effective tool to use when tackling challenges in an existing system. Using this tool assisted in the approach to reducing CLABSI in our NICU.

Surfactant replacement therapy: from biological basis to current clinical practice.

This review summarizes the current knowledge on the physiological action of endogenous and exogenous pulmonary surfactant, the role of different types of animal-derived and synthetic surfactants for RDS therapy, different modes of administration, potential risks and strategies of ventilation, and highlights the most promising aims for future development. Scientists have clarified the physicochemical properties and functions of the different components of surfactant, and part of this successful research is derived from the characterization of genetic diseases affecting surfactant composition or function. Knowledge from functional tests of surfactant action, its immunochemistry, kinetics and homeostasis are important also for improving therapy with animal-derived surfactant preparations and for the development of modified surfactants. In the past decade newly designed artificial surfactants and additives have gained much attention and have proven different advantages, but their particular role still has to be defined. For clinical practice, alternative administration techniques as well as postsurfactant ventilation modes, taking into account alterations in lung mechanics after surfactant placement, may be important in optimizing the potential of this most important drug in neonatology.

Phenotype characterisation of TBX4 mutation and deletion carriers with neonatal and paediatric pulmonary hypertension.

Rare variants in the T-box transcription factor 4 gene (TBX4) have recently been recognised as an emerging cause of paediatric pulmonary hypertension (PH). Their pathophysiology and contribution to persistent pulmonary hypertension in neonates (PPHN) are unknown. We sought to define the spectrum of clinical manifestations and histopathology associated with TBX4 variants in neonates and children with PH.We assessed clinical data and lung tissue in 19 children with PH, including PPHN, carrying TBX4 rare variants identified by next-generation sequencing and copy number variation arrays.Variants included six 17q23 deletions encompassing the entire TBX4 locus and neighbouring genes, and 12 likely damaging mutations. 10 infants presented with neonatal hypoxic respiratory failure and PPHN, and were subsequently discharged home. PH was diagnosed later in infancy or childhood. Three children died and two required lung transplantation. Associated anomalies included patent ductus arteriosus, septal defects, foot anomalies and developmental disability, the latter with a higher prevalence in deletion carriers. Histology in seven infants showed abnormal distal lung development and pulmonary hypertensive remodelling.TBX4 mutations and 17q23 deletions underlie a new form of developmental lung disease manifesting with severe, often biphasic PH at birth and/or later in infancy and childhood, often associated with skeletal anomalies, cardiac defects, neurodevelopmental disability and other anomalies.

Rapid and safe response to low-dose carbamazepine in neonatal epilepsy.

OBJECTIVE: To evaluate treatment responses in benign familial neonatal epilepsy (BFNE). METHODS: We recruited patients with BFNE through a multicenter international collaboration and reviewed electroclinical and genetic details, and treatment response. All patients were tested at minimum for mutations/deletions in the KCNQ2, KCNQ3, and SCN2A genes. RESULTS: Nineteen patients were included in this study. A family history of neonatal seizures was positive in 16 patients, and one additional patient had a family history of infantile seizures. Mutations or deletions of KCNQ2 were found in 14, and of KCNQ3 in 2, of the 19 patients. In all patients, seizures began at 2-5 days of life and occurred multiple times per day. Four patients developed status epilepticus. Seizures were focal, alternating between hemispheres, and characterized by asymmetric tonic posturing associated with apnea and desaturation, followed by unilateral or bilateral asynchronous clonic jerking. Twelve of 19 patients were treated with multiple medications prior to seizure cessation. Seventeen of (88%) 19 patients were seizure-free within hours of receiving oral carbamazepine (CBZ) or oxcarbazepine (OXC). Earlier initiation of CBZ was associated with shorter hospitalization (p < 0.01). No side effects of CBZ were reported. All patients had normal development and remain seizure-free at a mean follow-up period of 7.8 years (6 months-16 years). SIGNIFICANCE: This study provides evidence that CBZ is safe and rapidly effective in neonates with BFNE, even in status epilepticus. We propose that CBZ should be the drug of choice in benign familial neonatal seizures.

ABCA3, a key player in neonatal respiratory transition and genetic disorders of the surfactant system.

Genetic disorders of the surfactant system are rare diseases with a broad range of clinical manifestations, from fatal respiratory distress syndrome (RDS) in neonates to chronic interstitial lung disease (ILD) in children and adults. ABCA3 [ATP-binding cassette (ABC), subfamily A, member 3] is a lung-specific phospholipid transporter critical for intracellular surfactant synthesis and storage in lamellar bodies (LBs). Its expression is developmentally regulated, peaking prior to birth under the influence of steroids and transcription factors. Bi-allelic mutations of the ABCA3 gene represent the most frequent cause of congenital surfactant deficiency, indicating its critical role in lung function. Mutations affect surfactant lipid and protein processing and LBs' morphology, leading to partial or total surfactant deficiency. Approximately 200 mutations have been reported, most of which are unique to individuals and families, which makes diagnosis and prognosis challenging. Various types of mutations, affecting different domains of the protein, account in part for phenotype diversity. Disease-causing mutations have been reported in most coding and some non-coding regions of the gene, but tend to cluster in the first extracellular loop and the second nucleotide-binding domain (NBD), leading to defective glycosylation and trafficking defects and interfering with ATP binding and hydrolysis respectively. Mono-allelic damaging and benign variants are often subclinical but may act as disease modifiers in lung diseases such as RDS of prematurity or associate with mutations in other surfactant-related genes. Diagnosis is complex but essential and should combine pathology and ultrastructure studies on lung biopsy with broad-spectrum genetic testing of surfactant-related genes, made possible by recent technology advances in the massive parallel sequencing technology.

Dysregulation of locus coeruleus development in congenital central hypoventilation syndrome.

Human congenital central hypoventilation syndrome (CCHS), resulting from mutations in transcription factor PHOX2B, manifests with impaired responses to hypoxemia and hypercapnia especially during sleep. To identify brainstem structures developmentally affected in CCHS, we analyzed two postmortem neonatal-lethal cases with confirmed polyalanine repeat expansion (PARM) or Non-PARM (PHOX2B∆8) mutation of PHOX2B. Both human cases showed neuronal losses within the locus coeruleus (LC), which is important for central noradrenergic signaling. Using a conditionally active transgenic mouse model of the PHOX2B∆8 mutation, we found that early embryonic expression (

Surface film formation in vitro by infant and therapeutic surfactants: role of surfactant protein B.

BACKGROUND: Pulmonary surfactant provides an alveolar surface-active film that is critical for normal lung function. Our objective was to determine in vitro film formation properties of therapeutic and infant surfactants and the influence of surfactant protein (SP)-B content. METHODS: We used a multiwell fluorescent assay measuring maximum phospholipid surface accumulation (Max), phospholipid concentration required for half-maximal film formation (½Max), and time for maximal accumulation (tMax). RESULTS: Among five therapeutic surfactants, calfactant (highest SP-B content) had film formation values similar to natural surfactant, and addition of SP-B to beractant (lowest SP-B) normalized its Max value. Addition of budesonide to calfactant did not adversely affect film formation. In tracheal aspirates of preterm infants with evolving chronic lung disease, SP-B content correlated with ½Max and tMax values, and SP-B supplementation of SP-B-deficient infant surfactant restored normal film formation. Reconstitution of normal surfactant indicated a role for both SP-B and SP-C in film formation. CONCLUSION: Film formation in vitro differs among therapeutic surfactants and is highly dependent on SP-B content in infant surfactant. The results support a critical role of SP-B for promoting surface film formation.

New ATP-binding cassette A3 mutation causing surfactant metabolism dysfunction pulmonary type 3.

Respiratory distress syndrome (RDS) may occur in term and near-term infants because of mutations in surfactant-related genes. ATP-binding cassette A3 (ABCA3), a phospholipid carrier specifically expressed in the alveolar epithelium, is the most frequently involved protein. We report the case of a couple of late-preterm fraternal twin infants of opposite sex carrying the same compound heterozygous ABCA3 mutations, one of which has never been previously reported, with different disease severity, suggesting variable penetrance or sex-related differences. ABCA3 deficiency should be considered in term or near-term babies who develop unexplained RDS.

Pulmonary Hypertension in Developmental Lung Diseases.

Diverse genetic developmental lung diseases can present in the neonatal period with hypoxemic respiratory failure, often associated with with pulmonary hypertension. Intractable hypoxemia and lack of sustained response to medical management should increase the suspicion of a developmental lung disorder. Genetic diagnosis and lung biopsy are helpful in establishing the diagnosis. Early diagnosis can result in optimizing management and redirecting care if needed. This article reviews normal lung development, various developmental lung disorders that can result from genetic abnormalities at each stage of lung development, their clinical presentation, management, prognosis, and differential diagnoses.

Use of neonatal lung ultrasound in European neonatal units: a survey by the European Society of Paediatric Research.

OBJECTIVE: Regarding the use of lung ultrasound (LU) in neonatal intensive care units (NICUs) across Europe, to assess how widely it is used, for what indications and how its implementation might be improved. DESIGN AND INTERVENTION: International online survey. RESULTS: Replies were received from 560 NICUs in 24 countries between January and May 2023. LU uptake varied considerably (20%-98% of NICUs) between countries. In 428 units (76%), LU was used for clinical indications, while 34 units (6%) only used it for research purposes. One-third of units had <2 years of experience, and only 71 units (13%) had >5 years of experience. LU was mainly performed by neonatologists. LU was most frequently used to diagnose respiratory diseases (68%), to evaluate an infant experiencing acute clinical deterioration (53%) and to guide surfactant treatment (39%). The main pathologies diagnosed by LU were pleural effusion, pneumothorax, transient tachypnoea of the newborn and respiratory distress syndrome. The main barriers for implementation were lack of experience with technical aspects and/or image interpretation. Most units indicated that specific courses and an international guideline on neonatal LU could promote uptake of this technique. CONCLUSIONS: Although LU has been adopted in neonatal care in most European countries, the uptake is highly variable. The main indications are diagnosis of lung disease, evaluation of acute clinical deterioration and guidance of surfactant. Implementation may be improved by developing courses and publishing an international guideline.

Impaired surfactant protein B synthesis in infants with congenital diaphragmatic hernia.

Pulmonary hypoplasia and hypertension account for significant morbidity and mortality in neonates with congenital diaphragmatic hernia (CDH). Whether CDH is associated with surfactant dysfunction remains controversial. Therefore, we measured disaturated phosphatidylcholine (DSPC) and surfactant protein (SP)-B concentration in tracheal aspirates and their synthesis rate in infants with CDH compared to infants without lung disease. (2)H2O as a precursor of DSPC and 1-(13)C-leucine as a precursor of SP-B were administered to 13 infants with CDH and eight controls matched for gestational age. DSPC and SP-B were isolated from tracheal aspirates, and their fractional synthesis rate was derived from (2)H and (13)C enrichment curves obtained by mass spectrometry. DSPC and SP-B amounts in tracheal aspirates were also measured. In infants with CDH, SP-B fractional synthesis rate and amount were 62±27% and 57±22% lower, respectively, than the value found in infants without lung disease (p<0.01 and p<0.05, respectively). There were no significant group differences in DSPC fractional synthesis rate and amount. Infants with CDH have a lower rate of synthesis of SP-B and less SP-B in tracheal aspirates. In these infants, partial SP-B deficiency could contribute to the severity of respiratory failure and its correction might represent a therapeutic goal.

Ultrastructural characterization of genetic diffuse lung diseases in infants and children: a cohort study and review.

Pediatric diffuse lung diseases are rare disorders with an onset in the neonatal period or in infancy, characterized by chronic respiratory symptoms and diffuse interstitial changes on imaging studies. Genetic disorders of surfactant homeostasis represent the main etiology. Surfactant protein B and ABCA3 deficiencies typically cause neonatal respiratory failure, which is often lethal within a few weeks or months. Although heterozygous ABCA3 mutation carriers are mostly asymptomatic, there is growing evidence that monoallelic mutations may affect surfactant homeostasis. Surfactant protein C mutations are dominant or sporadic disorders leading to a broad spectrum of manifestations from neonatal respiratory distress syndrome to adult pulmonary fibrosis. The authors performed pathology and ultrastructural studies in 12 infants who underwent clinical lung biopsy. One carried a heterozygous SP-B mutation, 3 carried SP-C mutations, and 7 carried ABCA3 mutations (5 biallelic and 2 monoallelic). Optical microscopy made it possible to distinguish between surfactant-related disorders and other forms. One of the ABCA3 monoallelic carriers had morphological features of alveolar capillary dysplasia, a genetic disorder of lung alveolar, and vascular development. One patient showed no surfactant-related anomalies but had pulmonary interstitial glycogenosis, a developmental disorder of unknown origin. Electron microscopy revealed specific lamellar bodies anomalies in all SP-B, SP-C, and ABCA3 deficiency cases. In addition, the authors showed that heterozygous ABCA3 mutation carriers have an intermediate ultrastructural phenotype between homozygous carriers and normal subjects. Lung biopsy is an essential diagnostic procedure in unexplained diffuse lung disorders, and electron microscopy should be performed systematically, since it may reveal specific alterations in genetic disorders of surfactant homeostasis.

Towards personalized therapies for genetic disorders of surfactant dysfunction.

Genetic disorders of surfactant dysfunction are a rare cause of chronic, progressive or refractory respiratory failure in term and preterm infants. This review explores genetic mechanisms underpinning surfactant dysfunction, highlighting specific surfactant-associated genes including SFTPB, SFTPC, ABCA3, and NKX2.1. Pathogenic variants in these genes contribute to a range of clinical presentations and courses, from neonatal hypoxemic respiratory failure to childhood interstitial lung disease and even adult-onset pulmonary fibrosis. This review emphasizes the importance of early recognition, thorough phenotype assessment, and assessment of variant functionality as essential prerequisites for treatments including lung transplantation. We explore emerging treatment options, including personalized pharmacological approaches and gene therapy strategies. In conclusion, this comprehensive review offers valuable insights into the pathogenic mechanisms of genetic disorders of surfactant dysfunction, genetic fundamentals, available and emerging therapeutic options, and underscores the need for further research to develop personalized therapies for affected infants and children.