Congenital heart defects in Noonan syndrome: Diagnosis, management, and treatment

Mutation-induced LZTR1 polymerization provokes cardiac pathology in recessive Noonan syndrome

Noonan syndrome patients harboring causative variants in LZTR1 are particularly at risk to develop severe and early-onset hypertrophic cardiomyopathy. In this study, we investigate the mechanistic consequences of a homozygous variant LZTR1L580P by using patient-specific and CRISPR-Cas9-corrected induced pluripotent stem cell (iPSC) cardiomyocytes. Molecular, cellular, and functional phenotyping in combination with in silico prediction identify an LZTR1L580P-specific disease mechanism provoking cardiac hypertrophy. The variant is predicted to alter the binding affinity of the dimerization domains facilitating the formation of linear LZTR1 polymers. LZTR1 complex dysfunction results in the accumulation of RAS GTPases, thereby provoking global pathological changes of the proteomic landscape ultimately leading to cellular hypertrophy. Furthermore, our data show that cardiomyocyte-specific MRAS degradation is mediated by LZTR1 via non-proteasomal pathways, whereas RIT1 degradation is mediated by both LZTR1-dependent and LZTR1-independent pathways. Uni- or biallelic genetic correction of the LZTR1L580P missense variant rescues the molecular and cellular disease phenotype, providing proof of concept for CRISPR-based therapies.

Evaluation and Management of Chronic Heart Failure in Children and Adolescents With Congenital Heart Disease: A Scientific Statement From the American Heart Association

With continued medical and surgical advancements, most children and adolescents with congenital heart disease are expected to survive to adulthood. Chronic heart failure is increasingly being recognized as a major contributor to ongoing morbidity and mortality in this population as it ages, and treatment strategies to prevent and treat heart failure in the pediatric population are needed. In addition to primary myocardial dysfunction, anatomical and pathophysiological abnormalities specific to various congenital heart disease lesions contribute to the development of heart failure and affect potential strategies commonly used to treat adult patients with heart failure. This scientific statement highlights the significant knowledge gaps in understanding the epidemiology, pathophysiology, staging, and outcomes of chronic heart failure in children and adolescents with congenital heart disease not amenable to catheter-based or surgical interventions. Efforts to harmonize the definitions, staging, follow-up, and approach to heart failure in children with congenital heart disease are critical to enable the conduct of rigorous scientific studies to advance our understanding of the actual burden of heart failure in this population and to allow the development of evidence-based heart failure therapies that can improve outcomes for this high-risk cohort.

A case of systemic lupus erythematosus in a patient with Noonan syndrome with recurrent severe hypoglycaemia

Noonan syndrome (NS) is a dominantly inherited genetic disorder with mutations in genes encoding components or regulators of the Rat sarcoma virus/mitogen-activated protein kinase pathway. Its diagnosis is based on characteristic features, including typical facial features, a short stature, congenital heart disease, mild developmental delay, and cryptorchidism. Patients with NS sometimes develop autoimmune diseases, such as Hashimoto's thyroiditis and, rarely, systemic lupus erythematosus (SLE). We herein present a 29-year-old Japanese female with NS complicated by SLE and repeated severe hypoglycaemia. The patient was diagnosed with SLE based on thrombocytopenia, nephritis, a positive antinuclear antibody titre (1:640), and a positive anti-dsDNA antibody. The patient was treated with a glucocorticoid, mycophenolate mofetil, and tacrolimus, which attenuated both SLE and hypoglycaemia. Since insulin receptor antibody levels were higher to the upper normal range and decreased after treatment, hypoglycaemia probably appeared to be attributed to type B insulin resistance syndrome. We herein present the first case of SLE in NS complicated by type B insulin resistance syndrome. Although NS is a rare disease, we need to consider the complication of autoimmune diseases, including SLE.

Combined HRAS and NRAS ablation induces a RASopathy phenotype in mice

BACKGROUND

HRASKO/NRASKO double knockout mice exhibit exceedingly high rates of perinatal lethality due to respiratory failure caused by a significant lung maturation delay. The few animals that reach adulthood have a normal lifespan, but present areas of atelectasis mixed with patches of emphysema and normal tissue in the lung.

METHODS

Eight double knockout and eight control mice were analyzed using micro-X-ray computerized tomography and a Small Animal Physiological Monitoring system. Tissues and samples from these mice were analyzed using standard histological and Molecular Biology methods and the significance of the results analyzed using a Student´s T-test.

RESULTS

The very few double knockout mice surviving up to adulthood display clear craniofacial abnormalities reminiscent of those seen in RASopathy mouse models, as well as thrombocytopenia, bleeding anomalies, and reduced platelet activation induced by thrombin. These surviving mice also present heart and spleen hyperplasia, and elevated numbers of myeloid-derived suppressor cells in the spleen. Mechanistically, we observed that these phenotypic alterations are accompanied by increased KRAS-GTP levels in heart, platelets and primary mouse embryonic fibroblasts from these animals.

CONCLUSIONS

Our data uncovers a new, previously unidentified mechanism capable of triggering a RASopathy phenotype in mice as a result of the combined removal of HRAS and NRAS.

The Approach to a Child with Dysmorphic Features: What the Pediatrician Should Know

The advancement of genetic knowledge and the discovery of an increasing number of genetic disorders has made the role of the geneticist progressively more complex and fundamental. However, most genetic disorders present during childhood; thus, their early recognition is a challenge for the pediatrician, who will be also involved in the follow-up of these children, often establishing a close relationship with them and their families and becoming a referral figure. In this review, we aim to provide the pediatrician with a general knowledge of the approach to treating a child with a genetic syndrome associated with dysmorphic features. We will discuss the red flags, the most common manifestations, the analytic collection of the family and personal medical history, and the signs that should alert the pediatrician during the physical examination. We will offer an overview of the physical malformations most commonly associated with genetic defects and the way to describe dysmorphic facial features. We will provide hints about some tools that can support the pediatrician in clinical practice and that also represent a useful educational resource, either online or through apps downloaded on a smartphone. Eventually, we will offer an overview of genetic testing, the ethical considerations, the consequences of incidental findings, and the main indications and limitations of the principal technologies.

High frequency of hotspot mutation in PTPN11 gene among Moroccan patients with Noonan syndrome

Noonan syndrome (NS; OMIM 163950) is an autosomal dominant RASopathy with variable clinical expression and genetic heterogeneity. Clinical manifestations include characteristic facial features, short stature, and cardiac anomalies. Variants in protein-tyrosine phosphatase, non-receptor-type 11 (PTPN11), encoding SHP-2, account for about half of NS patients, SOS1 in approximately 13%, RAF1 in 10%, and RIT1 each in 9%. Other genes have been reported to cause NS in less than 5% of cases including SHOC2, RASA2, LZTR1, SPRED2, SOS2, CBL, KRAS, NRAS, MRAS, PRAS, BRAF, PPP1CB, A2ML1, MAP2K1, and CDC42. Several additional genes associated with a Noonan syndrome-like phenotype have been identified. Clinical presentation and variants in patients with Noonan syndrome are this study's objectives. We performed Sanger sequencing of PTPN11 hotspot (exons 3, 8, and 13). We report molecular analysis of 61 patients with NS phenotype belonging to 58 families. We screened for hotspot variants (exons 3, 8, and 13) in PTPN11 gene by Sanger sequencing. Twenty-seven patients were carrying heterozygous pathogenic variants of PTPN11 gene with a similar frequency (41.4%) compared to the literature. Our findings expand the variant spectrum of Moroccan patients with NS phenotype in whom the analysis of hotspot variants showed a high frequency of exons 3 and 8. This screening test allowed us to establish a molecular diagnosis in almost half of the patients with a good benefit-cost ratio, with appropriate management and genetic counseling.

RASopathies for Radiologists

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Natural history and outcomes in paediatric RASopathy-associated hypertrophic cardiomyopathy

AIMS

This study aimed to describe the natural history and predictors of all-cause mortality and sudden cardiac death (SCD)/equivalent events in children with a RASopathy syndrome and hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

This is a retrospective cohort study from 14 paediatric cardiology centres in the United Kingdom and Ireland. We included children <18 years with HCM and a clinical and/or genetic diagnosis of a RASopathy syndrome [Noonan syndrome (NS), NS with multiple lentigines (NSML), Costello syndrome (CS), cardiofaciocutaneous syndrome (CFCS), and NS with loose anagen hair (NS-LAH)]. One hundred forty-nine patients were recruited [111 (74.5%) NS, 12 (8.05%) NSML, 6 (4.03%) CS, 6 (4.03%) CFCS, 11 (7.4%) Noonan-like syndrome, and 3 (2%) NS-LAH]. NSML patients had higher left ventricular outflow tract (LVOT) gradient values [60 (36-80) mmHg, P = 0.004]. Over a median follow-up of 197.5 [inter-quartile range (IQR) 93.58-370] months, 23 patients (15.43%) died at a median age of 24.1 (IQR 5.6-175.9) months. Survival was 96.45% [95% confidence interval (CI) 91.69-98.51], 90.42% (95% CI 84.04-94.33), and 84.12% (95% CI 75.42-89.94) at 1, 5, and 10 years, respectively, but this varied by RASopathy syndrome. RASopathy syndrome, symptoms at baseline, congestive cardiac failure (CCF), non-sustained ventricular tachycardia (NSVT), and maximal left ventricular wall thickness were identified as predictors of all-cause mortality on univariate analysis, and CCF, NSVT, and LVOT gradient were predictors for SCD or equivalent event.

CONCLUSIONS

These findings highlight a distinct category of patients with Noonan-like syndrome with a milder HCM phenotype but significantly worse survival and identify potential predictors of adverse outcome in patients with RASopathy-related HCM.

Thoracic aortic aneurysm in an adolescent with intraoperative discovery of contained rupture: a case report

Background

As surgical recommendations in adults based on size criteria of ascending aortic aneurysms become more refined, criteria for childhood/adolescence remains less clear. Multiple pathologic factors may predispose younger patients to thoracic aortic aortopathy and increase the risk of rupture. An evolving field of research is how to identify thoracic aortic dilation earlier in patients, risk stratify, and to obtain objective measures beyond size for proceeding with surgical intervention in order to prevent catastrophic thoracic aortic dissection.

Case Description

We report an adolescent case of dilated ascending aortic aneurysm with a functionally unicuspid/bicuspid aortic valve. This patient was taken to surgery electively, given the gradual increasing size of the ascending aorta. Intraoperatively, there was an unexpected intraoperative finding of a contained aortic rupture. The patient underwent an aortic root replacement with mechanical valve composite graft and coronary artery reimplantation (modified Bentall) with ascending hemiarch replacement. The patient did well with no post-operative complications. Aortic pathology and genetic analysis were performed. The patient was discovered to have a heterozygous variant in PTPN11 which is typically associated with Noonan syndrome; however, this is not known to be associated with aortopathy.

Conclusions

As criteria for surgical intervention in adult thoracic ascending aortic aneurysms continues to evolve, this case illustrates challenges when determining the optimal criteria for surgical intervention in adolescent patients.

Preclinical evaluation of CRISPR-based therapies for Noonan syndrome caused by deep-intronic LZTR1 variants

Gene variants in LZTR1 are implicated to cause Noonan syndrome associated with a severe and early-onset hypertrophic cardiomyopathy. Mechanistically, LZTR1 deficiency results in accumulation of RAS GTPases and, as a consequence, in RAS-MAPK signaling hyperactivity, thereby causing the Noonan syndrome-associated phenotype. Despite its epidemiological relevance, pharmacological as well as invasive therapies remain limited. Here, personalized CRISPR-Cas9 gene therapies might offer a novel alternative for a curative treatment in this patient cohort. In this study, by utilizing a patient-specific screening platform based on iPSC-derived cardiomyocytes from two Noonan syndrome patients, we evaluated different clinically translatable therapeutic approaches using small Cas9 orthologs targeting a deep-intronic LZTR1 variant to cure the disease-associated molecular pathology. Despite high editing efficiencies in cardiomyocyte cultures transduced with lentivirus or all-in-one adeno-associated viruses, we observed crucial differences in editing outcomes in proliferative iPSCs vs. non-proliferative cardiomyocytes. While editing in iPSCs rescued the phenotype, the same editing approaches did not robustly restore LZTR1 function in cardiomyocytes, indicating critical differences in the activity of DNA double-strand break repair mechanisms between proliferative and non-proliferative cell types and highlighting the importance of cell type-specific screens for testing CRISPR-Cas9 gene therapies.

Mutations in PTPN11 could lead to a congenital myasthenic syndrome phenotype: a Noonan syndrome case series

The RASopathies are a group of genetic rare diseases caused by mutations affecting genes involved in the RAS/MAPK (RAS-mitogen activated protein kinase) pathway. Among them, PTPN11 pathogenic variants are responsible for approximately 50% of Noonan syndrome (NS) cases and, albeit to a lesser extent, of Leopard syndrome (LPRD1), which present a few overlapping clinical features, such as facial dysmorphism, developmental delay, cardiac defects, and skeletal deformities. Motor impairment and decreased muscle strength have been recently reported. The etiology of the muscle involvement in these disorders is still not clear but probably multifactorial, considering the role of the RAS/MAPK pathway in skeletal muscle development and Acetylcholine Receptors (AChR) clustering at the neuromuscular junction (NMJ). We report, herein, four unrelated children carrying three different heterozygous mutations in the PTPN11 gene. Intriguingly, their phenotypic features first led to a clinical suspicion of congenital myasthenic syndrome (CMS), due to exercise-induced fatigability with a variable degree of muscle weakness, and serum proteomic profiling compatible with a NMJ defect. Moreover, muscle fatigue improved after treatment with CMS-specific medication. Although the link between PTPN11 gene and neuromuscular transmission is unconfirmed, an increasing number of patients with RASopathies are affected by muscle weakness and fatigability. Hence, NS or LPDR1 should be considered in children with suspected CMS but negative genetic workup for known CMS genes or additional symptoms indicative of NS, such as facial dysmorphism or intellectual disability.

Coronary arteriopathy in a patient with Noonan phenotype: Case report

Noonan syndrome (NS) is a pleomorphic genetic disorder. Up to 50-80% of individuals have associated congenital heart disease. The scope of cardiac disease in NS is quite variable depending on the gene mutation. The most common forms of cardiac defects include pulmonary stenosis, hypertrophic cardiomyopathy (HCM), atrial septal defect and left-sided lesions. Amongst the rare vascular abnormalities few case reports have been mentioned about coronary artery lesions apart from sinus of Valsalva aneurysm, aortic dissection, intracranial aneurysm. This is a case report a rare case of asymptomatic coronary artery aneurysm in a young male with NS. There is lack of unified protocol for the screening, diagnosis, treatment, and follow-up of coronary artery disease in patients with NS. We conclude, echocardiography is sufficient in most cases in children. But a CT scan is appropriate in adults or when other lesions are suspected.

Co-Occurrence of Sensorineural Hearing Loss and Congenital Heart Disease: Etiologies and Management

OBJECTIVES/HYPOTHESIS

The co-occurrence of sensorineural hearing loss (SNHL) and congenital heart disease (CHD) is a rare condition with complex etiologies. The purpose of this study is to assess the etiologies, clinical features, and outcomes of cochlear implant (CI) in this patient population.

STUDY DESIGN

Case series and literature review.

METHODS

Clinical data of children who were diagnosed with SNHL and CHD and received CIs at a tertiary hospital from 2016 to 2021 were retrospectively analyzed. A literature review was performed to identify patients with SNHL and CHD.

FINDINGS

Of the 382 children who underwent cochlear implantation at our center, eight (2.1%) were diagnosed with SNHL and CHD. A literature review identified 1525 patients from 254 studies; the database therefore consisted of 1533 patients. The most common genetic etiologies of co-occurring SNHL and CHD were CHARGE syndrome (36.3%), Turner syndrome (8.4%), 22q11.2 deletion (3.0%), Noonan syndrome (2.9%), and Down syndrome (2.5%), whereas the most common non-genetic etiologies were congenital rubella syndrome (22.9%) and SNHL after early cardiac surgery (5.5%). Most of the patients presented with congenital, bilateral, severe-profound SNHL requiring early rehabilitation. Of the 126 children who received CIs at a median age of 2.5 years, half showed delayed speech development at last follow-up.

CONCLUSIONS

Co-occurring SNHL and CHD is a rare condition with complex etiologies. Timely hearing intervention with long-term follow-up and proper timing of heart surgery is essential for these children.

LEVEL OF EVIDENCE

4, case series Laryngoscope, 134:400-409, 2024.

The risk of attention-deficit hyperactivity disorder among children with congenital heart disease: A systematic review and meta-analysis

BACKGROUND

Although current treatments are effective in dealing with congenital heart disease (CHD), non-cardiac comorbidities such as attention-deficit hyperactivity disorder (ADHD) have received widespread attention. The purpose of this systematic review and meta-analysis is to assess the risk of ADHD associated with CHD.

METHODS

The literature search was carried out systematically through eight different databases by the end of September 2022. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. The heterogeneity of the studies was assessed by the Cochran Q test and the I2 statistic. Subgroup and sensitivity analyses were used to explore the potential sources of heterogeneity.

RESULTS

Eleven studies were included in this study, which involved a total of 296 741 participants. Our study showed that the children with CHD were at a significantly increased risk of ADHD compared with the reference group (OR = 2.98, 95% CI: 2.18-4.08). The results were moderately heterogeneous. These factors including study design, geographic region and study quality were identified as the first three of the most relevant heterogeneity moderators by subgroup analyses. Sensitivity analysis yielded consistent results. There was no evidence of publication bias.

CONCLUSIONS

The present study suggests that CHD children have a significantly higher risk of ADHD when compared with those without CHD. Early identification and intervention of ADHD is important to reduce its symptoms and adverse effects; therefore, clinicians should increase screening for ADHD in children with CHD and intervene promptly to reduce its effects whenever possible.

Cardiovascular Characteristics and Progressions of Hypertrophic Cardiomyopathy and Pulmonary Stenosis in RASopathy Syndrome in the Genomic Era

INTRODUCTION

To investigate cardiovascular characteristics and progressions of hypertrophic cardiomyopathy (HCM) and pulmonary stenosis (PS) and determine whether any genotype-phenotype correlations exist in patients with gene-confirmed RASopathy syndrome.

STUDY DESIGN

Eighty patients (male, 55%) confirmed as having RASopathy syndrome by genetic testing at a single tertiary center were enrolled. Subjects' medical and echocardiography records were reviewed and the changes in the z scores of left ventricular wall thickness (LVWT) and the degree of PS over time were examined during follow-up of 5.7 ± 3.1 and 7.5 ± 5.2 years, respectively.

RESULTS

The most common RASopathy gene identified was PTPN11 (56%), followed by RAF1 (10%). Eighty-five percent of patients had cardiovascular diseases, wherein 42% had HCM, and 38% PS. Mean maximal LVWT z score on the initial echocardiography (mean age 5.0 ± 6.0 years) was 3.4 ± 1.3 (median 2.8, range 2.1-6.6) in the HCM group. Overall, the maximal LVWT increased with time, especially in the HCM group (z = 3.4 ± 1.3 to 3.7 ± 1.6, P = .008) and RAF1-variant group (z = 3.7 ± 1.7 to 4.6 ± 1.8, P = .031). Five patients newly developed HCM during the study period. Genotype-phenotype correlation was significant for HCM (P = .002); 31% of patients with PTPN11 and 88% with RAF1 variants had HCM. PS did not progress in this study cohort.

CONCLUSIONS

In this study, progression of ventricular hypertrophy was seen in a significant number of patients with genotype correlation. Thus, long-term follow up of cardiovascular problems in patients with RASopathy is necessary.

The clinical value of color ultrasound screening for fetal cardiovascular abnormalities during the second trimester: A systematic review and meta-analysis

BACKGROUND

This meta-analysis aimed to investigate the diagnostic value of color ultrasound screening for fetal cardiovascular abnormalities during the second trimester in China.

METHODS

A literature search was conducted to evaluate the clinical value of color ultrasound screening for fetal cardiovascular abnormalities during the second trimester using English and Chinese databases. Numerical values for sensitivity and specificity were obtained from false-negative, false-positive, true-negative, and true-positive rates, presented alongside graphical representations with boxes marking the values and horizontal lines showing the confidence intervals. Summary receiver operating characteristic (SROC) curves were applied to assess the performance of the diagnostic tests. Data were processed using Review Manager 5.3.

RESULTS

Four studies (151 patients with fetal cardiovascular abnormalities and 3397 undiagnosed controls) met our evaluation criteria. The sensitivity was 0.91 and 0.96, respectively, and the specificity was 1.00. The Area Under the Curve (AUC) from the SROC curves was >90%; therefore, it was classified as excellent. Furthermore, there were 6 types of fetal cardiovascular abnormalities, and the pooled screening rate of atrioventricular septal defects was the highest.

CONCLUSION

Our meta-analysis showed that the use of color ultrasound during the second trimester can be an excellent diagnostic tool for fetal cardiovascular abnormalities.

Exome-wide analysis reveals role of LRP1 and additional novel loci in cognition

Cognitive functioning is heritable, with metabolic risk factors known to accelerate age-associated cognitive decline. Identifying genetic underpinnings of cognition is thus crucial. Here, we undertake single-variant and gene-based association analyses upon 6 neurocognitive phenotypes across 6 cognition domains in whole-exome sequencing data from 157,160 individuals of the UK Biobank cohort to expound the genetic architecture of human cognition. We report 20 independent loci associated with 5 cognitive domains while controlling for APOE isoform-carrier status and metabolic risk factors; 18 of which were not previously reported, and implicated genes relating to oxidative stress, synaptic plasticity and connectivity, and neuroinflammation. A subset of significant hits for cognition indicates mediating effects via metabolic traits. Some of these variants also exhibit pleiotropic effects on metabolic traits. We further identify previously unknown interactions of APOE variants with LRP1 (rs34949484 and others, suggestively significant), AMIGO1 (rs146766120; pAla25Thr, significant), and ITPR3 (rs111522866, significant), controlling for lipid and glycemic risks. Our gene-based analysis also suggests that APOC1 and LRP1 have plausible roles along shared pathways of amyloid beta (Aβ) and lipid and/or glucose metabolism in affecting complex processing speed and visual attention. In addition, we report pairwise suggestive interactions of variants harbored in these genes with APOE affecting visual attention. Our report based on this large-scale exome-wide study highlights the effects of neuronal genes, such as LRP1, AMIGO1, and other genomic loci, thus providing further evidence of the genetic underpinnings for cognition during aging.

Prenatal screening and diagnosis of pulmonary artery anomalies

Congenital pulmonary artery anomalies are rare. Their antenatal diagnosis requires good knowledge of fetal cardiac anatomy because their clinical presentation varies depending on the type and severity of the underlying lesion. Screening of these vascular anomalies can be straightforward in some cases because of significant associated consequences that are detected easily on ultrasound, while other anomalies have considerably less obvious features. There may be an associated genetic syndrome. The aim of this review was to define anomalies of the main pulmonary artery and its branches and to propose, through the identification of suspicious findings during routine antenatal heart examination, an optimal screening method for the pulmonary artery pathway. We propose that pulmonary artery anomalies can be classified antenatally into four types of disorder. Herein we describe 14 cases subgrouped accordingly as: anomalies of the pulmonary valvular region, with stenosis or atresia of the valve (n = 4); conotruncal abnormalities (n = 4); anomalies associated with abnormal origin or course of the pulmonary artery (n = 4); and anomalies associated with abnormal growth of the pulmonary artery and its branches (n = 2). We highlight the need to differentiate the three-vessel view from the three-vessel-and-trachea view when assessing a fetus with a congenital pulmonary artery anomaly. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Cardiomyocyte hyperplasia and immaturity but not hypertrophy are characteristic features of patients with RASopathies

AIMS

RASopathies are caused by mutations in genes that alter the MAP kinase pathway and are marked by several malformations with cardiovascular disorders as the predominant cause of mortality. Mechanistic insights in the underlying pathogenesis in affected cardiac tissue are rare. The aim of the study was to assess the impact of RASopathy causing mutations on the human heart.

METHODS AND RESULTS

Using single cell approaches and histopathology we analyzed cardiac tissue from children with different RASopathy-associated mutations compared to age-matched dilated cardiomyopathy (DCM) and control hearts. The volume of cardiomyocytes was reduced in RASopathy conditions compared to controls and DCM patients, and the estimated number of cardiomyocytes per heart was ~4-10 times higher. Single nuclei RNA sequencing of a 13-year-old RASopathy patient (carrying a PTPN11 c.1528C > G mutation) revealed that myocardial cell composition and transcriptional patterns were similar to <1 year old DCM hearts. Additionally, immaturity of cardiomyocytes is shown by an increased MYH6/MYH7 expression ratio and reduced expression of genes associated with fatty acid metabolism. In the patient with the PTPN11 mutation activation of the MAP kinase pathway was not evident in cardiomyocytes, whereas increased phosphorylation of PDK1 and its downstream kinase Akt was detected.

CONCLUSION

In conclusion, an immature cardiomyocyte differentiation status appears to be preserved in juvenile RASopathy patients. The increased mass of the heart in such patients is due to an increase in cardiomyocyte number (hyperplasia) but not an enlargement of individual cardiomyocytes (hypertrophy).

Multimodality Imaging in Noonan Syndrome: Case Series of Young Children

Noonan syndrome (NS) is an autosomal dominant disorder characterized by distinctive facial anomalies, growth failure, and a wide spectrum of cardiac abnormalities. Here, the clinical presentation, multimodality imaging characteristics, and management in a case series of four patients with NS are presented. Multimodality imaging showed frequently biventricular hypertrophy accompanied by biventricular outflow tract obstruction and pulmonary stenosis, similar late gadolinium enhancement pattern, and elevation of native T1 and extracellular volume, which may serve as multimodality imaging features in NS to aid in patient diagnosis and treatment. Keywords: Pediatrics, Echocardiography, MR Imaging, Cardiac Supplemental material is available for this article. © RSNA, 2023.

Changes of RAS Pathway Phosphorylation in Lymphoblastoid Cell Lines from Noonan Syndrome Patients Carrying Hypomorphic Variants in Two NS Genes

Noonan syndrome (NS) is an autosomal dominant multisystem disorder, characterized by variable expressivity and locus heterogeneity, being caused by mutations in one of a subset of RAS pathway genes. Nevertheless, for 20-30% of patients it is not possible to provide molecular diagnosis, suggesting that further unknown genes or mechanisms are involved in NS pathogenesis. Recently, we proposed a digenic inheritance of subclinical variants as an alternative NS pathogenic model in two NS patients negative for molecular diagnosis. They showed hypomorphic variants of RAS pathway genes co-inherited from both their healthy parents that we hypothesized to generate an additive effect. Here, we report on the phosphoproteome and proteome analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) performed on the immortalized peripheral blood mononuclear cells (PBMCs) from the two above trios. Our results indicate that the two unrelated patients show overlapped profiles in both protein abundances and their phosphorylation levels not reached by their parents. IPA software predicted RAS-related pathways as significantly activated in the two patients. Interestingly, they remained unchanged or only slightly activated in both patients' parents. These findings suggest that the presence of one subclinical variant can activate the RAS pathway below the pathological threshold, which can instead be exceeded by the additive effect due to the co-presence of two subclinical variants causing NS, supporting our digenic inheritance hypothesis.

Autosomal recessive Noonan-like syndrome caused by homozygosity for a previously unreported variant in SPRED2

Noonan syndrome is characterized by variable phenotypic expressivity with characteristic dysmorphic facial features, varying degrees of intellectual disability, developmental delay, short stature, and congenital heart defects in 50-80%. Other findings include a webbed neck, cryptorchidism, coagulation defects and eye abnormalities. Thus far, Noonan syndrome has mainly been attributed to heterozygous pathogenic variants in 10+ different genes, with the rare exception of cases due to biallelic pathogenic variants in LZTR1. Recently, homozygous loss-of-function variants in SPRED2 have been identified as a cause of a recessive Noonan syndrome-like phenotype. We present the phenotypes of two additional patients with homozygosity for a previously unreported loss-of-function variant in SPRED2, thereby adding relevant clinical information about the recently described Noonan syndrome-like SPRED2-related phenotype.

The role of the pregnancy heart team in clinical practice

Significant maternal and fetal morbidity and mortality risk has been shown to be associated with cardiovascular disease in pregnancy. Several determinants, such as the increasing number of females with corrected congenital heart disease in reproductive age, a more advanced maternal age associated with cardiovascular risk factors, and a greater prevalence of preexisting comorbidities related to cardiac disorders such as cancer and COVID-19), lead to a higher incidence of cardiac complications in pregnancy in the last few decades. However, adopting a multidisciplinary strategy may influence maternal and neonatal outcomes. This review aims at assessing the role of the Pregnancy Heart Team, which should ensure careful pre-pregnancy counseling, pregnancy monitoring, and delivery planning for both congenital and other cardiac or metabolic disorders, addressing several emerging aspects in the multidisciplinary team-based approach.

RASopathies and spinal deformities for screening of scoliosis

BACKGROUND

The RASopathies (Noonan syndrome [NS] and Costello syndrome [CS]) are rare disorders. Although these have been characterized, precise delineation of the differences in the spinal deformities associated with RASopathy has not been described. This study characterized the spinal deformities found in NS and CS and describes a strategy for the screening of scoliosis.

METHODS

The clinical records and spinal X-rays of 35 consecutive NS and CS patients were reviewed. Spinal X-rays were assessed to define the presence and progression of scoliosis. Clinical records were examined to identify the risk factors associated with scoliosis. In addition, we investigated the association between clinical records and scoliosis using logistic regression analysis.

RESULTS

Twenty-four patients with NS and 11 with CS were included. Nine patients with NS and five with CS showed scoliosis. The mean ± SD age at diagnosis was 12.6 ± 2.4 years in NS and 11.4 ± 2.5 years in CS (p = 0.55), and mean follow-up period was 4.8 ± 2.6 years and 6.3 ± 2.4 years (p = 0.42), respectively. The coronal angular deformity at final follow-up was 27.3 ± 8.5° in NS and 19.4 ± 6.9° in CS (p = 0.030) with a mean annual progression of 2.8 ± 1.1° in NS 1.0 ± 1.0° in CS (p = 0.030). Cardiac disease was present in eight out of nine patients with NS with concomitant scoliosis in NS, and significantly more than in CS (p = 0.007). PTPN11 significantly correlated with scoliosis (odds ratio 12.4 0.035, 95% confidence interval: 1.20-128.00).

CONCLUSIONS

Spinal deformity in NS is more severe than in CS. This study identified a relationship between PTPN11 and scoliosis. Therefore, PTPN11 can be used for the screening of scoliosis.

Management of nutritional and gastrointestinal issues in RASopathies: A narrative review

Noonan, Costello, and cardio-facio-cutaneous syndrome are neurodevelopmental disorders belonging to the RASopathies, a group of syndromes caused by alterations in the RAS/MAPK pathway. They are characterized by similar clinical features, among which feeding difficulties, growth delay, and gastro-intestinal disorders are frequent, causing pain and discomfort in patients. Hereby, we describe the main nutritional and gastrointestinal issues reported in individuals with RASopathies, specifically in Noonan syndrome, Noonan syndrome-related disorders, Costello, and cardio-facio-cutaneous syndromes. Fifty percent of children with Noonan syndrome may experience feeding difficulties that usually have a spontaneous resolution by the second year of life, especially associated to genes different than PTPN11 and SOS1. More severe manifestations often require artificial enteral nutrition in infancy are observed in Costello syndrome, mostly associated to c.34G>A substitution in the HRAS gene. In cardio-facio-cutaneous syndrome feeding issues are usually present (90-100% of cases), especially in individuals carrying variants in BRAF, MAP2K1, and MAP2K2 genes, and artificial enteral intervention, even after scholar age, may be required. Moreover, disorders associated with gastrointestinal dysmotility as gastro-esophageal reflux and constipation are commonly reported in all the above-mentioned syndromes. Given the impact on growth and on the quality of life of these patients, early evaluation and prompt personalized management plans are fundamental.

The heart in RASopathies

The cardiovascular phenotype associated with RASopathies has expanded far beyond the original descriptions of pulmonary valve stenosis by Dr Jaqueline Noonan in 1968 and hypertrophic cardiomyopathy by Hirsch et al. in 1975. Because of the common underlying RAS/MAPK pathway dysregulation, RASopathy syndromes usually present with a typical spectrum of overlapping cardiovascular anomalies, although less common cardiac defects can occur. The identification of the causative genetic variants has enabled the recognition of specific correlations between genotype and cardiac phenotype. Characterization and understanding of genotype-phenotype associations is not only important for counseling a family of an infant with a new diagnosis of a RASopathy condition but is also critical for their clinical prognosis with respect to cardiac disease, neurodevelopment and other organ system involvement over the lifetime of the patient. This review will focus on the cardiac manifestations of the most common RASopathy syndromes, the relationship between cardiac defects and causal genetic variation, the contribution of cardiovascular abnormalities to morbidity and mortality and the most relevant follow-up issues for patients affected by RAS/MAPK pathway diseases, with respect to cardiac clinical outcomes and management, in children and in the adult population.

The Effect of Growth Hormone Therapy on Cardiac Outcomes in Noonan Syndrome: Long Term Follow-up Results

OBJECTIVE

Cardiac involvement is common in Noonan syndrome (NS). Concerns have been raised regarding the effect of recombinant growth hormone (rGH) use on ventricular wall thickness and a possible increased risk of cardiac side effects. This study aimed to investigate the effect of rGH on the development of hypertrophic cardiomyopathy and other cardiac findings in NS.

METHODS

Patients under the age of 18 years and diagnosed with NS according to the Van der Burgt criteria, were included. Patients were divided into two groups according to those receiving rGH or not at the time of obtaining cardiac measurements. Before and after the treatment, electrocardiographic and echocardiographic (ECHO) assessments were made, including interventricular septal thickness, left ventricular internal diameter, and left ventricular posterior thickness. Results were expressed as Z scores.

RESULTS

Twenty-four NS subjects (16 boys, eight girls) were included. At the beginning of the follow up, the overall height standard deviation score was -2.56±0.94. Sixteen were on rGH. The mean rGH treatment duration was 8.3±3.8 years, and the mean dose was 0.22±0.04 mg/kg/week. The final height was 169±8.2 cm, and 10 of 11 patients who reached the final height received rGH. There was no difference between the rGH and non-rGH groups in terms of ECHO parameters pre-and post-treatment.

CONCLUSION

In this cohort, there was no change in ECHO parameters on rGH and during follow-up. These results suggest that rGH is safe in NS patients with cardiac pathology under close follow-up.

Clinical analysis of Noonan syndrome caused by RRAS2 mutations and literature review

Noonan syndrome is a common developmental disorder characterized by distinctive facial dysmorphism, short stature, congenital heart defects, pectus deformity, and developmental delay. It is related to the abnormal activation of genes involved in the RAS-MAPK signaling pathway, more than a dozen of which can be affected. However, mutations of the RRAS2 gene are rare, with only 6 different RRAS2 variants in 13 patients reported to date. In this case report, whole-exome sequencing revealed a novel heterozygous variant in the RRAS2 gene NM_012250: c.212G > A, p.(Gly71Glu). Phenotypically, our patient had typical Noonan syndrome-related clinical manifestations consistent with published reports, such as short stature, facial dysmorphism, short neck, patent foramen ovale, moderate global developmental delay, and hearing impairment. In addition, our patient also had a distal middle finger deformity and hair defect, which have not been reported in previous cases. We analyzed the clinical characteristics of all patients with Noonan syndrome caused by RRAS2 variants and reviewed the literature. This discovery expands the genetic and phenotypic spectrum of Noonan syndrome.

Modeling (not so) rare developmental disorders associated with mutations in the protein-tyrosine phosphatase SHP2

Src homology region 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2) is a highly conserved protein tyrosine phosphatase (PTP), which is encoded by PTPN11 and is indispensable during embryonic development. Mutations in PTPN11 in human patients cause aberrant signaling of SHP2, resulting in multiple rare hereditary diseases, including Noonan Syndrome (NS), Noonan Syndrome with Multiple Lentigines (NSML), Juvenile Myelomonocytic Leukemia (JMML) and Metachondromatosis (MC). Somatic mutations in PTPN11 have been found to cause cancer. Here, we focus on the role of SHP2 variants in rare diseases and advances in the understanding of its pathogenesis using model systems.

Clinical Findings in Children with Noonan Syndrome—A 17-Year Retrospective Study in an Oral Surgery Center

To date, only a limited number of publications have studied the specific oral and maxillofacial findings in patients diagnosed with Noonan syndrome (NS), which is an example of a genetically heterogeneous RASopathy. In this retrospective study, we aimed to ascertain the genotype–phenotype correlations between genetic mutations and certain diagnoses in the field of oral surgery. We collected surgical and genetic data from 42 children (median age, 12 years) who had a confirmed diagnosis of NS and underwent surgery in the Department of Oral Surgery, Medical University of Lodz, over a 17-year period, from 2004 to 2021. In total, 17 patients with mutations of the PTPN11 gene were diagnosed with over-retained deciduous teeth and supernumerary teeth. An amount of 7 patients with mutations of the SOS1 gene were diagnosed with mandibular compound odontomas. Finally, 12 patients with mutations of the LZTR1 gene were diagnosed with bilateral or unilateral central giant cell granulomas in the mandible. Although craniofacial features of many genetic disorders have been previously described in the literature, this study determined the genotype–phenotype correlations in the field of oral surgery.

Noonan syndrome associated with hypoplastic left heart syndrome

Noonan syndrome is an inherited disorder caused by alterations in the RAS-MAPK pathway. There have been several identified genotype-phenotype associations made with respect to congenital cardiac lesions and Noonan syndrome variants, but limited data exist regarding single ventricle disease in this population. Here, we report two patients with PTPN11-related Noonan syndrome and hypoplastic left heart syndrome variants.

Cardiovascular Abnormalities and Gene Mutations in Children With Noonan Syndrome

Background: Common cardiac abnormalities in Noonan syndrome (NS) include congenital heart diseases (CHD), pulmonary valve stenosis and hypertrophic cardiomyopathy (HCM). Molecular diagnoses are enabling earlier and more precise diagnosis of patients who have a subtle or atypical presentation. The aims of this study were to investigate genotype-phenotype associations with respect to Noonan syndrome (NS)-associated cardiac abnormalities and catheter or surgery-based interventions conditions.

Methods: From January 2019 to December 2021, 22 children with a confirmed molecular diagnosis of NS combined with cardiovascular abnormalities were consecutively enrolled into the current study. A comprehensive review was carried out of echocardiography and electrocardiogram results, second-generation whole-exome sequencing results and catheter or surgery-based interventions conditions.

Results: The main manifestations of electrocardiogram abnormalities were QTc prolongation, abnormal Q wave in the precordial lead and limb lead, right ventricular hypertrophy and left or right deviation of the electrical axis. The most commonly detected abnormality was pulmonary valve dysplasia with stenosis, seen in 15 (68.2%) patients, followed by atrial septal defect in 11 (50%) patients. Seven genes (RAF1, RIT1, SOS1, PTPN11, BRAF, SOS2, and LZTR1) were found to contain disease-associated variants. The most commonly observed genetic mutations were PTPN11 (27%) and RAF1 (27%). Each genotype was associated with specific phenotypic findings. RIT1, SOS1, PTPN11, and SOS2 had common echocardiography features characterized by pulmonary valve stenosis, while RAF1 was characterized by HCM. Interestingly, patients with BRAF mutations were not only characterized by HCM, but also by pulmonary valve stenosis. In the cohort there was only one patient carrying a LZTR1 mutation characterized by left ventricle globose dilation. Ten cases underwent catheter or surgery-based interventions. All the operations had immediate results and high success rates. However, some of the cases had adverse outcomes during extended follow-up. Based on the genotype-phenotype associations observed during follow-up, BRAF and RAF1 genotypes seem to be poor prognostic factors, and multiple interventions may be required for NS patients with severe pulmonary stenosis or myectomy for HCM.

Conclusions: The identification of causal genes in NS patients has enabled the evaluation of genotype-cardiac phenotype relationships and prognosis of the disease. This may be beneficial for the development of therapeutic approaches.

Expanding the novel MAPKAPK5-related developmental disorder's genotype-phenotype correlation: Patient report and 19 months of follow-up

This study aimed to widen the knowledge of a recently identified, autosomal‐recessive, multiple congenital anomalies syndrome to date observed in only other three children. This is the second report of biallelic mutations in MAPKAPK5 whose impairment during human development has been associated with neurological, cardiac, and facial anomalies combined with fingers and toes malformations. Through the affected patients' genetic and phenotypic features overlap, this report confirms MAPKAPK5 as causative gene and adds unique neurodevelopmental characterization. Moreover, based on the complex congenital genitourinary anomalies reported and MAPKAPK5 literature review, we also propose kidney and external genitalia involvement as a key syndromic feature whose expressivity may be more severe in males.

Cardiac features of Noonan syndrome in Japanese patients

BACKGROUND

Cardiovascular disease is one of the most important problems in long-term follow-up for Noonan syndrome. We examined cardiovascular issues and clinical manifestations, with a focus on the cardiovascular disease and prognosis of patients with Noonan syndrome.

METHODS

This single-centre study evaluated patients who were clinically and genetically diagnosed with Noonan syndrome.

RESULTS

Forty-three patients diagnosed with Noonan syndrome were analysed. The most prevalent responsible mutation was found in PTPN11 (25/43). The second and third most prevalent causative genes were SOS1 (6/43) and RIT1 (5/43), respectively, and 67.4% of genetically diagnosed patients with Noonan syndrome had structural cardiovascular abnormalities. Pulmonary valve stenosis was prevalent in patients with mutations in PTPN11 (8/25), SOS1 (4/6), and RIT1 (4/5). Hypertrophic cardiomyopathy was found in two of three patients with mutations in RAF1. There was no difference in the cardiovascular events or cardiovascular disease prevalence in patients with or without PTPN11 mutations. The proportion of RIT1 mutation-positive patients who underwent intervention due to cardiovascular disease was significantly higher than that of patients with PTPN11 mutations. Patients who underwent any intervention for pulmonary valve stenosis exhibited significantly higher pulmonary flow velocity than patients who did not undergo intervention, when they visited our hospital for the first time. All patients who underwent intervention for pulmonary valve stenosis had a pulmonary flow velocity of more than 3.0 m/s at first visit.

CONCLUSIONS

These findings suggest that genetic information can provide a clinical prognosis for cardiovascular disease and may be part of genotype-based follow-up in Noonan syndrome.

PTPN11 Gene Mutations and Its Association with the Risk of Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital birth defect, with a prevalence of 8.98‰ of all live births in China. PTPN11 has been known to be closely involved in heart developments. In this research, we carried out whole-exome sequencing in nine CHD families and identified eight rare deleterious missense variants of PTPN11 gene in nine probands by stringently filtering criteria. Sanger sequencing of these probands and their unaffected familiar members revealed that six damaging variants were de novo in seven CHD families. Then, targeted sequencing was used to assess the PTPN11 exon variants in 672 sporadic CHD cases and 399 unrelated controls and identified 7 deleterious missense variants in 8 patients. Fisher's exact test reveals a significant association of PTPN11 variations with CHD (P = 0.0289). We observed the distribution of different subtypes in CHD patients with PTPN11 variants and found atrial septal defect (ASD) is a prominent phenotype (58.8%, 10/17). In vitro functional assays revealed that the predicted PTPN11 variants disturb RAS-mitogen-activated protein kinase signaling activity by influencing the phosphorylation level of pathway proteins and increasing the proliferation and migration abilities of cardiomyocytes to different extents. Our findings demonstrated that PTPN11 variants were associated with increased risk of CHD development and may be served as an important susceptible genetic event for CHD, especially the ASD subphenotype.

Diagnosis and Management of Rare Cardiomyopathies in Adult and Paediatric Patients. A Position Paper of the Italian Society of Cardiology (SIC) and Italian Society of Paediatric Cardiology (SICP)

Cardiomyopathies (CMPs) are myocardial diseases in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality. Thought for a long time to be rare diseases, it is now clear that most of the CMPs can be easily observed in clinical practice. However, there is a group of specific heart muscle diseases that are rare in nature whose clinical/echocardiographic phenotypes resemble those of the four classical morphological subgroups of hypertrophic, dilated, restrictive, arrhythmogenic CMPs. These rare CMPs, often but not solely diagnosed in infants and paediatric patients, should be more properly labelled as specific CMPs. Emerging consensus exists that these conditions require tailored investigation and management. Indeed, an appropriate understanding of these conditions is mandatory for early treatment and counselling. At present, however, the multisystemic and heterogeneous presentation of these entities is a challenge for clinicians, and time delay in diagnosis is a significant concern. The aim of this paper is to define practical recommendations for diagnosis and management of the rare CMPs in paediatric or adult age. A modified Delphi method was adopted to grade the recommendations proposed by each member of the writing committee.

Perioperative anaphylaxis to fibrin sealants in children with Noonan Syndrome: A retrospective study

BACKGROUND

In the diagnosis of perioperative anaphylaxis, it is essential to define its cause to prevent future reexposures, especially in children with Noonan Syndrome who are characterized by a large number of systemic features and wide-ranging dysmorphia. From an oral surgeon's point of view, apart from an increased risk of tumor incidence, diverse hematologic anomalies are of high concern.

OBJECTIVE

Perioperative management of such patients often requires the use of fibrin sealants, which contain aprotinin. A certain number of anaphylaxis cases have been observed in our daily practice during such treatment, which was the reason for this evaluation.

METHODS

The study was conducted to retrospectively review perioperative anaphylaxis grade II and above in children with Noonan Syndrome who underwent surgeries in the Department of Oral Surgery, Medical University of Lodz, between 2006 and 2021.

RESULTS

Out of the 16 cases of suspected anaphylaxis to aprotinin, 14 were observed in children with Noonan Syndrome. The postoperative serologic screening revealed positive results for qualitative aprotinin-specific immunoglobulin (Ig) G, highly elevated quantitative aprotinin-specific IgG, and slightly elevated aprotinin-specific IgE antibodies. Interestingly, previous aprotinin administration or contact in the past 12 months was excluded.

CONCLUSION

Given that fibrin sealants are typically used in various surgical practices and although the anaphylaxis reactions in such cases are rare, it is essential to be cautious in patients with RASopathies who are at a high risk of developing anaphylaxis.

Supravalvular pulmonary stenosis: A risk factor for reintervention in Noonan syndrome with pulmonary valve stenosis

To assess the short- and long-term outcomes of balloon pulmonary valvuloplasty (BPV) in children with Noonan syndrome (NS). Pulmonary stenosis (PS) is the most common congenital heart lesion in NS. BPV is the accepted first line treatment in PS. However, BPV in NS patients has been reported to be less effective, without specific factors for the need for reintervention being identified. Retrospective case-note review of all patients with NS who underwent BPV between 1985 and 2020. Patients were divided into 2 groups: those with supravalvular pulmonary stenosis (SPS) in addition to valvar PS, and those with isolated valvar PS. A cohort of 54 patients with NS underwent BPV at a median of 275 (interquartile range [IQR]: 108-575) days of age. SPS was present in 32 (59%) patients whereas 22 had (41) isolated PS. The preprocedural invasive gradient was 47 (IQR: 35-69) mmHg, and 44 (IQR: 35-48) mmHg in those with SPS and those without respectively (p = 0.88). Reintervention was required in 22 patients (41%): 17 (77%) -with SPS and 5 (23%) without (p = 0.017). Fourteen patients (11 with SPS) required surgical reintervention and 8 (6 with SPS) required further BPV. There was no significant difference in the age at initial BPV, pre- and postprocedural gradients and interval until reintervention between groups. This is the largest reported cohort of patients with NS undergoing BPV. Although BPV is often successful, the reintervention rates are high. SPS was a risk factor for reintervention.

Pediatric Hypertrophic Cardiomyopathy: Exploring the Genotype-Phenotype Association

Pediatric hypertrophic cardiomyopathy (HCM) is the most common form of cardiomyopathy in children and a leading cause of sudden cardiac death. Yet, the association between genotype variation, phenotype expression, and adverse events in pediatric HCM has not been fully elucidated. Although the literature on this topic is evolving in adult HCM, the evidence in children is lacking. Solidifying our understanding of this relationship could improve risk stratification as well as improve our comprehension of the underlying pathophysiological characteristics of pediatric HCM. In this state‐of‐the‐art review, we examine the current literature on genetic variations in HCM and their association with outcomes in children, discuss the current approaches to identifying cardiovascular phenotypes in pediatric HCM, and explore possible avenues that could improve sudden cardiac death risk assessment.

Cardiomyopathies in Children and Systemic Disorders When Is It Useful to Look beyond the Heart?

Cardiomyopathy (CMP) is a rare disease in the pediatric population, with a high risk of morbidity and mortality. The genetic etiology of CMPs in children is extremely heterogenous. These two factors play a major role in the difficulties of establishing standard diagnostic and therapeutic protocols. Isolated CMP in children is a frequent finding, mainly caused by sarcomeric gene variants with a detection rate that can reach up to 50% of analyzed cohorts. Complex multisystemic forms of pediatric CMP are even more heterogenous. Few studies in literature take into consideration this topic as the main core since it represents a rarity (systemic CMP) within a rarity (pediatric population CMP). Identifying etiology in this cohort is essential for understanding prognosis, risk stratification, eligibility to heart transplantation and/or mechanical-assisted procedures, preventing multiorgan complications, and relatives' recurrence risk calculation. The previous points represent a cornerstone in patients' empowerment and personalized medical care approach. The aim of this work is to propose a new approach for an algorithm in the setting of the diagnostic framework of systemic pediatric CMP. On the other hand, during the literature review, we noticed a relatively common etiologic pattern in some forms of complex/multisystem CMP. In other words, certain syndromes such as Danon, Vici, Alström, Barth, and Myhre syndrome share a common pathway of directly or indirectly defective "autophagy" process, which appears to be a possible initiating/triggering factor for CMPs. This conjoint aspect could be important for possible prognostic/therapeutic implications in this category of patients. However, multicentric studies detailed functional and experimental models are needed prior to deriving conclusions.

Case report: Clinical manifestations and genotype analysis of a child with PTPN11 and SEC24D mutations

BACKGROUND

The PTPN11 gene, located at 12q24. 13, encodes protein tyrosine phosphatase 2C. Mutations in the PTPN11 gene can lead to various phenotypes, including Noonan syndrome and LEOPARD syndrome. The SEC24D gene is located at 4q26 and encodes a component of the COPII complex, and is closely related to endoplasmic reticulum protein transport. Mutations in SEC24D can lead to Cole-Carpenter syndrome-2. To date, dual mutations in these two genes have not been reported in the literature.

METHODS

We report a patient with short stature and osteogenesis imperfecta as the primary clinical manifestation. Other clinical features were peculiar facial features, deafness, and a history of recurrent fractures. Whole exome sequencing was performed on this patient.

RESULTS

After whole-exome sequencing, three mutations in two genes were identified that induced protein alterations associated with the patient's phenotype. One was a de novo variant c.1403C>T (p.Thr468Met) on exon 12 of the PTPN11 gene, and the other was a compound heterozygous mutation in the SEC24D gene, a novel variant c.2609_2610delGA (p.Arg870Thrfs^*10) on exon 20 and a reported variant c.938G>A (p.Arg313His) on exon 8.

CONCLUSIONS

Concurrent mutations in PTPN11 and SEC24D induced a phenotype that was significantly different from individual mutations in either PTPN11 or SEC24D gene. Personalized genetic analysis and interpretation could help us understand the patient's etiology and hence develop treatments and improve the prognosis of these patients.

Differences in severity of cardiovascular anomalies in children with Noonan syndrome based on the causative gene

BACKGROUND

Noonan syndrome (NS) is a genetic syndrome, characterized by various dysmorphic features, cardiac anomalies, short stature, and developmental delay. NS is a leading cause of cardiovascular anomalies. The syndrome results from dysregulation in the RAS-MAPK pathway and is related to the RASopathy family syndromes. Pathogenic variants in more than 20 related genes have been identified in association with NS, and several genotype-phenotype correlations were suggested. The specific severity of the same cardiovascular anomalies has not been described as linked to a specific causative gene.

METHODS

For this retrospective, single-center study, data retrieved from medical charts of a multidisciplinary NS clinic included genetic diagnosis, cardiac malformations, the need for intervention, demographics, and prenatal diagnosis. We analyzed molecular genetics and the severity of cardiac malformations.

RESULTS

The cohort comprised 74 children with NS. Consistent with previous studies, pathogenic variants in PTPN11 were the most common (62%). Cardiovascular anomalies presented in 57%; pulmonary stenosis (PS) was the most common (about 79% of anomalies). In children with pathogenic variants in PTPN11, PS tended to be more severe and required intervention in 53%, compared to 25% of children with PS and a variant in other genes.

CONCLUSION

This first Israeli cohort of NS showed similar rates of cardiac malformations and genetic breakdown as previously published. Variants in PTPN11 were prone to a higher risk for severe PS that requires intervention. This finding may assist in genetic counseling and cardiac treatment decisions, and stresses the importance of genetic in addition to clinical diagnosis of NS.

Genetic conditions of short stature: A review of three classic examples

Noonan, Turner, and Prader-Willi syndromes are classical genetic disorders that are marked by short stature. Each disorder has been recognized for several decades and is backed by extensive published literature describing its features, genetic origins, and optimal treatment strategies. These disorders are accompanied by a multitude of comorbidities, including cardiovascular issues, endocrinopathies, and infertility. Diagnostic delays, syndrome-associated comorbidities, and inefficient communication among the members of a patient's health care team can affect a patient's well-being from birth through adulthood. Insufficient information is available to help patients and their multidisciplinary team of providers transition from pediatric to adult health care systems. The aim of this review is to summarize the clinical features and genetics associated with each syndrome, describe best practices for diagnosis and treatment, and emphasize the importance of multidisciplinary teams and appropriate care plans for the pediatric to adult health care transition.

Hypertrophic Cardiomyopathy in RASopathies: Diagnosis, Clinical Characteristics, Prognostic Implications, and Management

RASopathies are multisystemic disorders caused by germline mutations in genes linked to the RAS/mitogen-activated protein kinase pathway. Diagnosis of RASopathy can be triggered by clinical clues ("red flags") which may direct the clinician toward a specific gene test. Compared with sarcomeric hypertrophic cardiomyopathy, hypertrophic cardiomyopathy in RASopathies (R-HCM) is associated with higher prevalence of congestive heart failure and shows increased prevalence and severity of left ventricular outflow tract obstruction. Biventricular involvement and the association with congenital heart disease, mainly pulmonary stenosis, have been commonly described in R-HCM. The aim of this review is to assess the prevalence and unique features of R-HCM and to define the available therapeutic options.

Severe Bleeding During Orthognathic Surgery for a Noonan Syndrome Patient

Noonan syndrome (NS) is a genetic disorder characterized by craniofacial dysmorphism, chest deformities, congenital heart defects, and bleeding disorders. Although patients with NS have a high prevalence of orofacial deformity, few reports are available on their anesthetic management during orthognathic surgery. This case report describes a 31-year-old female with NS, anemia, hypertrophic cardiomyopathy, and mild mitral valve regurgitation who experienced severe bleeding during orthognathic surgery. After treating her anemia with oral iron therapy and subcutaneous epoetin β, 4 units of autologous blood was deposited prior to surgery. General anesthesia was induced with remifentanil and propofol and maintained with sevoflurane, remifentanil, and fentanyl. Despite mild hypotensive anesthesia (targeted mean arterial pressure of 65 mm Hg) with nitroglycerine and intravenous tranexamic acid for bleeding, adequate hemostasis was difficult to achieve and led to severe blood loss (1442 mL). Therefore, the 4 units of autologous blood and 2 units of packed red blood cells were transfused. Her postoperative course proceeded uneventfully without abnormal postoperative bleeding. Because patients with NS can have difficulty with hemostasis, vascular malformations, and fragile blood vessels, extensive hematologic evaluation and thorough preparation for unexpected bleeding are crucial to accomplish orthognathic surgery.

Current diagnosis and management of rare pediatric diseases in China

This review categorizes and summarizes the rare pediatric diseases that have been included in the First List of Rare Diseases that was jointly published by the National Health Commission and four other government departments in China in 2018. In total, 58 diseases that develop during childhood are included. These diseases involve nine organ systems, including the musculoskeletal, respiratory, immune, endocrine and metabolic, nervous, cardiovascular, hematological, urinary, and integumentary systems. Affected children often have multiorgan involvement with various presentations. Severe diseases can cause acute symptoms starting in the neonatal period that lead to increased morbidity and mortality without prompt management. Early diagnosis and treatment can significantly change the course of a disease and improve its prognosis. This work systemically reviews the status of rare pediatric diseases with a relatively high incidence in the First List of Rare Diseases.

Management of cardiac aspects in children with Noonan syndrome - results from a European clinical practice survey among paediatric cardiologists

BACKGROUND

The majority of children with Noonan syndrome (NS) or other diseases from the RASopathy spectrum suffer from congenital heart disease. This study aims to survey cardiac care of this patient cohort within Europe.

METHODS

A cross-sectional exploratory survey assessing the treatment and management of patients with NS by paediatric endocrinologists, cardiologists and clinical geneticists was developed. This report details responses of 110 participating paediatric cardiologists from multiple countries.

RESULTS

Most paediatric cardiologists responding to the questionnaire were associated with university hospitals, and most treated <10 patients/year with congenital heart disease associated with the NS spectrum. Molecular genetic testing for diagnosis confirmation was initiated by 81%. Half of the respondents reported that patients with NS and congenital heart disease typically present <1y of age, and that a large percentage of affected patients require interventions and pharmacotherapy early in life. A higher proportion of infant presentation and need for pharmacotherapy was reported by respondents from Germany and Sweden than from France and Spain (p = 0.031; p = 0.014; Fisher's exact test). Older age at first presentation was reported more from general hospitals and independent practices than from university hospitals (p = 0.031). The majority of NS patients were followed at specialist centres, but only 37% reported that their institution offered dedicated transition clinic to adult services. Very few NS patients with hypertrophic cardiomyopathy (HCM) were reported to carry implantable cardioverter defibrillators for sudden cardiac death prevention. Uncertainty was evident in regard to growth hormone treatment in patients with NS and co-existing HCM, where 13% considered it not a contra-indication, 24% stated they did not know, but 63% considered HCM either a possible (20%) or definite (15%) contraindication, or a cause for frequent monitoring (28%). Regarding adverse reactions for patients with NS on growth hormone therapy, 5/19 paediatric cardiology respondents reported a total of 12 adverse cardiac events.

CONCLUSIONS

Congenital heart disease in patients with NS or other RASopathies is associated with significant morbidity during early life, and specialty centre care is appropriate. More research is needed regarding the use of growth hormone in patients with NS with congenital heart disease, and unmet medical needs have been identified.

Genotype-cardiac phenotype correlations in a large single-center cohort of patients affected by RASopathies: Clinical implications and literature review

Congenital heart disease (CHD) and hypertrophic cardiomyopathy (HCM) are common features in patients affected by RASopathies. The aim of this study was to assess genotype- phenotype correlations, focusing on the cardiac features and outcomes of interventions for cardiac conditions, in a single-center cohort of 116 patients with molecularly confirmed diagnosis of RASopathy, and compare these findings with previously published data. All enrolled patients underwent a comprehensive echocardiographic examination. Relevant information was also retrospectively collected through the analysis of clinical records. As expected, significant associations were found between PTPN11 mutations and pulmonary stenosis (both valvular and supravalvular) and pulmonary valve dysplasia, and between SOS1 mutations and valvular defects. Similarly, HRAS mutations were significantly associated with HCM. Potential associations between less prevalent mutations and cardiac defects were also observed, including RIT1 mutations and HCM, SOS2 mutations and septal defects, and SHOC2 mutations and septal and valve abnormalities. Patients with PTPN11 mutations were the most likely to require both a primary treatment (transcatheter or surgical) and surgical reintervention. Other cardiac anomalies less reported until recently in this population, such as isolated functional and structural mitral valve diseases, as well as a sigmoid-shaped interventricular septum in the absence of HCM, were also reported. In conclusion, our study confirms previous data but also provides new insights on cardiac involvement in RASopathies. Further research concerning genotype/phenotype associations in RASopathies could lead to a more rational approach to surgery and the consideration of drug therapy in patients at higher risk due to age, severity, anatomy, and comorbidities.