Biventricular Hypertrophic Cardiomyopathy in a 26-year-old Nigerian Woman with Noonan Syndrome.

BACKGROUND: Cardiac disorders are found in about half of cases of Noonan syndrome (NS). The most common congenital heart diseases in this syndrome include pulmonary valvular stenosis obstructive or nonobstructive hypertrophic cardiomyopathy (17%). Biventricular hypertrophic cardiomyopathy (HCM) is very rare in this condition. OBJECTIVE: The objective is to report a case of biventricular hypertrophic cardiomyopathy in a 26-year-old Nigerian female with the phenotype. METHODS: This is a descriptive case report. RESULTS: The patient presented with dyspnoea on exertion which started at the age of 7 years and has progressively worsened. There was associated precordial chest pain and palpitation. Clinical examination revealed a young woman, who is small for her age. She had some dysmorphic features such as a webbed neck, lowset ears, low posterior hairline, crowded teeth, high arched palate, a small and asymmetric chin and a high carrying angle at the elbows. The pulses were synchronous and there was no radio-radial or radiofemoral delay and her blood pressures were within normal limits. Cardiac auscultation was unremarkable. The 12-lead ECG showed biventricular hypertrophy with a strain pattern. The echocardiogram showed features in keeping with biventricular hypertrophic cardiomyopathy. CONCLUSION: Biventricular HCM is relatively uncommon in Noonan syndrome. Patients with typical dysmorphia should have a full cardiac evaluation to look for these anomalies.

CONTEXTE: Des troubles cardiaques sont présents chez environ la moitié des patients atteints du syndrome de Noonan. Les cardiopathies congénitales les plus fréquentes dans ce syndrome incluent la sténose valvulaire pulmonaire (60 %), la communication interauriculaire (25 %) et la cardiomyopathie hypertrophique obstructive ou non obstructive (17 %). La cardiomyopathie hypertrophique (HCM) biventriculaire est très rare dans ces conditions. OBJECTIF: L'objectif est de rapporter un cas de cardiomyopathie hypertrophique biventriculaire chez une femme nigériane de 26 ans présentant le phénotype. MÉTHODES: Il s'agit d'un rapport de cas descriptif. RÉSULTATS: La patiente s'est présentée avec une dyspnée à l'effort, débutant à l'âge de 7 ans et s'aggravant progressivement. Il y avait des douleurs précordiales associées ainsi que des palpitations. L'examen clinique a révélé une jeune femme, petite pour son âge, avec quelques traits dysmorphiques tels qu'un cou palmé, des oreilles basses, une implantation basse des cheveux à l'arrière, des dents serrées, un palais ogival, un menton petit et asymétrique et un angle de port élevé au niveau des coudes. Les pouls étaient synchrones, sans retard radio-radial ou radiofémoral, et la tension artérielle était dans les limites normales. L'auscultation cardiaque n'a révélé aucune anomalie. L'électrocardiogramme à 12 dérivations a montré une hypertrophie biventriculaire avec un pattern de strain. L'échocardiogramme a révélé des caractéristiques compatibles avec une cardiomyopathie hypertrophique biventriculaire. CONCLUSION: La cardiomyopathie hypertrophique biventriculaire est relativement rare dans le syndrome de Noonan. Les patients présentant une dysmorphie typique devraient subir une évaluation cardiaque complète afin de détecter ces anomalies. MOTS CLÉS: Syndrome de Noonan, Dysmor phie, Cardiomyopathie hypertrophique.

Social Communication in Ras Pathway Disorders: A Comprehensive Review from Genetics to Behavior in Neurofibromatosis Type 1 and Noonan Syndrome.

Neurofibromatosis type 1 (NF1) and Noonan syndrome (NS) are neurogenetic syndromes caused by pathogenetic variants encoding components of the Ras-ERK-MAPK signaling pathway (Ras pathway). NF1 and NS are associated with differences in social communication and related neuropsychiatric risks. During the last decade, there has been growing interest in Ras-linked syndromes as models to understand social communication deficits and autism spectrum disorders. We systematically review the literature between 2010-2023 focusing on the social communication construct of the RDoC framework. We provide an integrative summary of the research on facial and non-facial social communication processes in NF1 and NS across molecular, cellular, neural circuitry, and behavioral domains. At the molecular and cellular levels, dysregulation in the Ras pathway is intricately tied to variations in social communication through changes in GABAergic, glutamatergic, and serotonergic transmission, as well as inhibitory/excitatory imbalance. Neural circuitry typically associated with learning, attention, and memory in NF1 and NS (e.g., cortico-striatal connectivity), is also implicated in social communication. We highlight less researched, potential mechanisms for social communication, such as white matter connectivity and the default mode network. Finally, key gaps in NF1 and NS literature are identified and a roadmap for future research is provided. By leveraging genetic syndromes research, we can understand the mechanisms associated with behaviors and psychiatric disorders.

Noonan Syndrome and Celiac Disease in an Adolescent With Short Stature and Delayed Puberty.

Background/Objective: We present an adolescent male with Noonan syndrome (NS) and celiac disease (CD) who attained normal adult height with growth hormone (GH) treatment and gluten-free diet (GFD). Case Report: A 15 ½ year old healthy male presented with short stature and delayed puberty. His mother and maternal grandmother were short with heights 142.2 cm and 147.3 cm, respectively. Examination showed bilateral epicanthal folds and down slanting eyes like his mother, fifth finger clinodactyly, height 147.5 cm (<1%; standard deviation score, -2.96), growth velocity 2.5 cm/y, weight 48.2 kg (11%; standard deviation score, -1.24), Tanner 2 pubic hair and Tanner 1 genitalia. Midparental target height was 169.1 cm. He had normal screening studies for GH deficiency and thyroid disorders, prepubertal gonadotropins and testosterone levels, and normal total immunoglobulin A, and elevated antitissue transglutaminase immunoglobulin A 134.7units/mL (0-20). Bone age was 13 years. Genetic evaluation revealed heterozygous missense variant of BRAF gene in him and his mother confirming a diagnosis of NS. He was diagnosed with CD by intestinal biopsy. Patient was started on GH therapy and a GFD with subsequent improvement in growth velocit (6.8-12.3 cm/y) and advancement of puberty. The patient stopped GH therapy at 17 ½ years with a height 165.9 cm. Discussion: Coexistence of NS caused by BRAF missense variant and CD has not been previously reported. Our patient attained normal adult height with GH therapy and GFD. Conclusion: NS and CD can co-occur and addressing both these disorders can help patients attain normal height potential.

An Unexpected Finding of a PTPN11 Germline Mutation in a Patient With a Melanocytic Lesion With a Somatic MAP2K1 Mutation. Coincidence or Not?

Melanocytic tumors are a diverse group of lesions and are traditionally classified based on a combination of clinical presentation as well as histological examination. More recently, molecular diagnostics has become an increasingly important part of differentiating different melanocytic lesions in the current WHO standards. This molecular testing, however, can result in unexpected findings. In this report, we describe that molecular testing of a clinical atypical melanocytic lesion showed a mutation in the MAP2K1 gene as well as an unexpected germline mutation in PTPN11, indicative of Noonan syndrome. Based on these findings we concluded that the patient had a MAP2K1 associated melanocytic lesion with Noonan syndrome as an incidental finding. Melanomas are classically not associated with Noonan syndrome. However, we hypothesized that the germline mutations of PTPN11 and the somatic second hit mutation in the MAP2K1 genes might be involved in the formation of the aforementioned lesion. As they are both part of the RAS-MAPK pathway. Furthermore, with the expansion of molecular diagnostics in melanomas, we expect to find an increase in unexpected (germline) mutations.

Evaluation of Growth Characteristics and Final Heights of Cases Diagnosed with Noonan Syndrome on GH Treatment.

Introduction: Proportional short stature is one of the most important features of Noonan Syndrome, and adult height often remains below the 3rd percentile. Although the pathophysiology of short stature in NS patients is not fully understood, it has been shown that GH treatment is beneficial in NS, and it significantly improves the height in respect to the results of short and long-term GH treatment. Methods: In this study, the efficacy of GH therapy was evaluated in children and adolescents with Noonan syndrome who attained final height. In this national cohort study, 67 cases with NS who reached final height from 14 centers were evaluated. Results: A total of 53 cases (mean follow-up time 5.6 years) received GH treatment. Height SDS of the subjects who were started on GH tended to be shorter than those who did not receive GH (-3.26± 1.07 vs. -2.53 ±1.23) at initial presentation. The mean final height and final height SDS in girls using GH vs those not using GH were 150.1 cm and -2.17 SD vs 47.4 cm and-2.8 SD, respectively. The mean final height and final height SDS in boys using GH vs. not using GH were 162.48 ± 6.19 cm and -1.81 SD vs 157.46 ± 10.16 cm and -2.68 ± 1.42 SD, respectively. The Δheight SDS value of the cases was significantly higher in the group receiving GH than in those not receiving GH (1.36 ± 1.12 SD vs. -0.2 ± 1.24, p<0.001). Cardiac findings remained stable in two patients with hypertrophic cardiomyopathy who received GH treatment. No significant side effects were observed in the cases during follow-up. Conclusion: In patients with Noonan syndrome who reach their final height, a significant increase in height is observed with GH treatment, and an increase of approximately +1.4 SDS can be achieved. It has been concluded that GH treatment is safe and effective.

A Case Report of Verheij Syndrome.

Verheij syndrome (VRJS) is a rare genetic disorder characterized by a range of developmental issues and physical abnormalities. This condition is caused by mutations or deletions in the PUF60 (poly-U-binding factor 60 kDa) gene, which is located on the long arm of chromosome 8, specifically in the q24.3 region. We present a unique case of an 11-year-old girl child with VRJS. The child presented with absence seizures. She was noted to have short stature, spina bifida of the lower cervical vertebrae, and a smaller right kidney on ultrasonography. This case expands the phenotypic spectrum of VRJS by demonstrating a milder presentation, highlighting the importance of a high index of suspicion for the diagnosis, even in atypical presentations. Whole exome sequencing identified the causative mutation, confirming the diagnosis. Growth hormone therapy was initiated for short stature but discontinued due to the subsequent development of idiopathic intracranial hypertension. Additionally, this report represents the first documented case of VRJS in India, emphasizing the importance of global data sharing and collaboration for improving the understanding and management of rare genetic disorders.

Severe generalized edema in a premature neonate: A case report and literature review.

Key Clinical Message: With no family history, and an atypical phenotype, the clinical diagnosing of Noonan syndrome (NS) can be very difficult. The present case emphasized that generalized edema in neonates may be the potential first symptom of NS. Abstract: Severe generalized edema is a rare pathological condition with high mortality in newborns, in particular the premature infants. It is characterized by the extensive subcutaneous tissue edema and the accumulation of fluid in neonatal body fluid compartments. The etiology and pathogenesis of hydrops in neonates are quite complex. Generally speaking, hydrops can be divided into immune hydrops and non-immune hydrops according to the etiology. It is still challenging in treating severe neonatal edema. In this study, we presented a preterm newborn with severe generalized edema after birth, which was finally diagnosed with Noonan syndrome (NS). The infant clinically manifested as severe generalized edema alone, without the involvement of multiple organ malformation. Generalized edema in neonates was probably the first symptom of NS. Therefore, differential diagnosis of NS is necessary for infants developing generalized edema.

Diagnostic challenge of cutis Verticis Gyrata (CVG) in a patient presenting clinical features of Noonan or turner syndrome.

Cutis Verticis Gyrata (CVG) is an uncommon condition, often classified as primary (idiopathic) or secondary to other diseases or syndromes. Its pathogenesis remains poorly understood, and its association with genetic syndromes is particularly rare. Noonan and Turner syndromes are distinct genetic disorders with characteristic phenotypes and multiple systemic involvements. This report aims to highlight the diagnostic complexities when CVG presents in the backdrop of these syndromes. A 38 years old patient was presented with chief complaints of receding hairline, dropping eyelids, cerebral deformations with deep furrows and thickened dermis. On the basis of patient's complaints, Noonan or turner syndrome was considered as possible diagnosis. This particular report presents a case of patient suffering from CVG having history of noonan and turner syndrome. With the detailed MRI, histology etc. CVG was finally confirmed. The novelty of this case lies in its rarity, diagnostic complexity, and the need for a multidisciplinary approach to unravel and manage the intersecting conditions. It contributes valuable insights to the existing medical literature, enhancing our understanding of the interplay between dermatological and genetic conditions. Patients with Noonan and turner syndrome exhibit clinical signs and symptoms that are strikingly similar to those of CVG, suggesting that this presents a significant diagnostic problem. An unfavorable outcome could arise from delayed or incorrect diagnosis. Because of this, it is recommended that healthcare fraternities should include uncommon illnesses like CVG as differential diagnosis. Considering CVG in differential diagnosis is crucial for early identification, accurate diagnosis, and comprehensive management. It ensures that associated systemic and genetic conditions are not overlooked and that patients receive holistic and personalized care.

Parenting Stress Index in Caregivers of Individuals With Noonan Syndrome.

Medical professionals frequently underestimate stress level of parents/caregivers of patients with rare disorders as RASopathies, the latter might experience elevated stress levels, with their own health frequently overlooked despite significant responsibilities and hurdles encountered. The aim of this study is to assess the stress experienced by parents of individuals with Noonan syndrome and related conditions. Forty-eight parents (20 fathers; 28 mothers), among the 31 recruited families, completed the Italian version of the Parenting Stress Index-Short Form. Our study shows abnormally elevated scores (≥ 85° percentile) in 35.4% of parents. Data retrieved from subscales reveal a perception of a difficult child in 25% of cases, a dysfunctional parental-child interaction in 20.8%, a general parental distress in 10.4% of cases, and an elevated overall stress in 18.8% of parents. Questionnaires as the Parenting Stress Index-Short Form are valuable tools to evaluate stress in parents/caregivers of children with RASopathies. Evaluation by professionals is fundamental to support parents and caregivers in managing stressors and to enhance their quality of life and relationships. To prevent stress escalation and parents' burnout, an early assessment to tailor a timely treatment should be introduced as soon as possible as good clinical practice.

Transient Myeloproliferative Disorder (TMD), Acute Lymphoblastic Leukemia (ALL), and Juvenile Myelomonocytic Leukemia (JMML) in a Child with Noonan Syndrome: Sequential Occurrence, Single Center Experience, and Review of the Literature.

Noonan syndrome (NS) is an autosomal dominant disorder that varies in severity and can involve multiple organ systems. In approximately 50% of cases, it is caused by missense mutations in the PTPN11 gene (12q24.13). NS is associated with a higher risk of cancer occurrence, specifically hematological disorders. Here, we report a case of a child who was diagnosed at birth with a transient myeloproliferative disorder (TMD). After two years, the child developed hyperdiploid B-cell precursor acute lymphoblastic leukemia (BCP-ALL), receiving a two-year course of treatment. During her continuous complete remission (CCR), a heterozygous germline mutation in the PTPN11 gene [c.218 C>T (p.Thr73lle)] was identified. At the age of ten, the child presented with massive splenomegaly, hyperleukocytosis, and thrombocytopenia, resulting in the diagnosis of juvenile myelomonocytic leukemia (JMML). After an initial response to antimetabolite therapy (6-mercaptopurine), she underwent haploidentical hematopoietic stem cell transplantation (HSCT) and is currently in complete remission. The goal of this review is to gain insight into the various hematological diseases associated with NS, starting from our unique case.

Molecular characterization of gliomas and glioneuronal tumors amid Noonan syndrome: cancer predisposition examined.

Introduction: In the setting of pediatric and adolescent young adult cancer, increased access to genomic profiling has enhanced the detection of genetic variation associated with cancer predisposition, including germline syndromic conditions. Noonan syndrome (NS) is associated with the germline RAS pathway activating alterations and increased risk of cancer. Herein, we describe our comprehensive molecular profiling approach, the association of NS with glioma and glioneuronal tumors, and the clinical and histopathologic characteristics associated with the disease. Methods: Within an institutional pediatric cancer cohort (n = 314), molecular profiling comprised of paired somatic disease-germline comparator exome analysis, RNA sequencing, and tumor classification by DNA methylation analysis was performed. Results: Through the implementation of paired analysis, this study identified 4 of 314 (1.3%) individuals who harbored a germline PTPN11 variant associated with NS, of which 3 individuals were diagnosed with a glioma or glioneuronal tumor. Furthermore, we extend this study through collaboration with a peer institution to identify two additional individuals with NS and a glioma or glioneuronal tumor. Notably, in three of five (60%) individuals, paired genomic profiling led to a previously unrecognized diagnosis of Noonan syndrome despite an average age of cancer diagnosis of 16.8 years. The study of the disease-involved tissue identified signaling pathway dysregulation through somatic alteration of genes involved in cellular proliferation, survival, and differentiation. Discussion: Comparative pathologic findings are presented to enable an in-depth examination of disease characteristics. This comprehensive analysis highlights the association of gliomas and glioneuronal tumors with RASopathies and the potential therapeutic challenges and importantly demonstrates the utility of genomic profiling for the identification of germline cancer predisposition.

Impact of pathogenic variants of the Ras-mitogen-activated protein kinase pathway on major white matter tracts in the human brain.

Noonan syndrome and neurofibromatosis type 1 are genetic conditions linked to pathogenic variants in genes of the Ras-mitogen-activated protein kinase signalling pathway. Both conditions hyper-activate signalling of the Ras-mitogen-activated protein kinase pathway and exhibit a high prevalence of neuropsychiatric disorders. Further, animal models of Noonan syndrome and neurofibromatosis type 1 and human imaging studies show white matter abnormalities in both conditions. While these findings suggest Ras-mitogen-activated protein kinas pathway hyper-activation effects on white matter, it is unknown whether these effects are syndrome-specific or pathway-specific. To characterize the effect of Noonan syndrome and neurofibromatosis type 1 on human white matter's microstructural integrity and discern potential syndrome-specific influences on microstructural integrity of individual tracts, we collected diffusion-weighted imaging data from children with Noonan syndrome (n = 24), neurofibromatosis type 1 (n = 28) and age- and sex-matched controls (n = 31). We contrasted the clinical groups (Noonan syndrome or neurofibromatosis type 1) and controls using voxel-wise, tract-based and along-tract analyses. Outcomes included voxel-wise, tract-based and along-tract fractional anisotropy, axial diffusivity, radial diffusivity and mean diffusivity. Noonan syndrome and neurofibromatosis type 1 showed similar patterns of reduced fractional anisotropy and increased axial diffusivity, radial diffusivity, and mean diffusivity on white matter relative to controls and different spatial patterns. Noonan syndrome presented a more extensive spatial effect than neurofibromatosis type 1 on white matter integrity as measured by fractional anisotropy. Tract-based analysis also demonstrated differences in effect magnitude with overall lower fractional anisotropy in Noonan syndrome compared to neurofibromatosis type 1 (d = 0.4). At the tract level, Noonan syndrome-specific effects on fractional anisotropy were detected in association tracts (superior longitudinal, uncinate and arcuate fasciculi; P < 0.012), and neurofibromatosis type 1-specific effects were detected in the corpus callosum (P < 0.037) compared to controls. Results from along-tract analyses aligned with results from tract-based analyses and indicated that effects are pervasive along the affected tracts. In conclusion, we find that pathogenic variants in the Ras-mitogen-activated protein kinase pathway are associated with white matter abnormalities as measured by diffusion in the developing brain. Overall, Noonan syndrome and neurofibromatosis type 1 show common effects on fractional anisotropy and diffusion scalars, as well as specific unique effects, namely, on temporoparietal-frontal tracts (intra-hemispheric) in Noonan syndrome and on the corpus callosum (inter-hemispheric) in neurofibromatosis type 1. The observed specific effects not only confirm prior observations from independent cohorts of Noonan syndrome and neurofibromatosis type 1 but also inform on syndrome-specific susceptibility of individual tracts. Thus, these findings suggest potential targets for precise, brain-focused outcome measures for existing medications, such as MEK inhibitors, that act on the Ras-mitogen-activated protein kinase pathway.

Cardiac Phenotype and Gene Mutations in RASopathies.

Cardiac involvement is a major feature of RASopathies, a group of phenotypically overlapping syndromes caused by germline mutations in genes encoding components of the RAS/MAPK (mitogen-activated protein kinase) signaling pathway. In particular, Noonan syndrome (NS) is associated with a wide spectrum of cardiac pathologies ranging from congenital heart disease (CHD), present in approximately 80% of patients, to hypertrophic cardiomyopathy (HCM), observed in approximately 20% of patients. Genotype-cardiac phenotype correlations are frequently described, and they are useful indicators in predicting the prognosis concerning cardiac disease over the lifetime. The aim of this review is to clarify the molecular mechanisms underlying the development of cardiac diseases associated particularly with NS, and to discuss the main morphological and clinical characteristics of the two most frequent cardiac disorders, namely pulmonary valve stenosis (PVS) and HCM. We will also report the genotype-phenotype correlation and its implications for prognosis and treatment. Knowing the molecular mechanisms responsible for the genotype-phenotype correlation is key to developing possible targeted therapies. We will briefly address the first experiences of targeted HCM treatment using RAS/MAPK pathway inhibitors.

Heterozygosity for loss-of-function variants in LZTR1 is associated with isolated multiple café-au-lait macules.

PURPOSE: Pathogenic LZTR1 variants cause schwannomatosis and dominant/recessive Noonan syndrome (NS). We aim to establish an association between heterozygous loss-of-function LZTR1 alleles and isolated multiple café-au-lait macules (CaLMs). METHODS: A total of 849 unrelated participants with multiple CaLMs, lacking pathogenic/likely pathogenic NF1 and SPRED1 variants, underwent RASopathy gene panel sequencing. Data on 125 individuals with heterozygous LZTR1 variants were collected for characterizing their clinical features and the associated molecular spectrum. In vitro functional assessment was performed on a representative panel of missense variants and small in-frame deletions. RESULTS: Analysis revealed heterozygous LZTR1 variants in 6.0% (51/849) of participants, exceeding the general population prevalence. LZTR1-related CaLMs varied in number, displayed sharp or irregular borders, and were generally isolated but occasionally associated with features recurring in RASopathies. In 2 families, CaLMs and schwannomas co-occurred. The molecular spectrum mainly consisted of truncating variants, indicating loss-of-function. These variants substantially overlapped with those occurring in schwannomatosis and recessive NS. Functional characterization showed accelerated protein degradation or mislocalization, and failure to downregulate mitogen-activated protein kinase signaling. CONCLUSION: Our findings expand the phenotypic variability associated with LZTR1 variants, which, in addition to conferring susceptibility to schwannomatosis and causing dominant and recessive NS, occur in individuals with isolated multiple CaLMs.

Observation and Management of Juvenile Myelomonocytic Leukemia and Noonan Syndrome-Associated Myeloproliferative Disorder: A Real-World Experience.

Juvenile Myelomonocytic Leukemia (JMML) is a rare and clonal hematopoietic disorder of infancy and early childhood with myeloproliferative/myelodysplastic features resulting from germline or somatic mutations in the RAS pathway. Treatment is not uniform, with management varying from observation to stem cell transplant. The aim of our retrospective review is to describe the treatment and outcomes of a cohort of patients with JMML or Noonan Syndrome-associated Myeloproliferative Disorder (NS-MPD) to provide management guidance for this rare and heterogeneous disease. We report on 22 patients with JMML or NS-MPD managed at three institutions in the Texas Medical Center. Of patients with known genetic mutations and cytogenetics, 6 harbored germline mutations, 12 had somatic mutations, and 9 showed cytogenetic abnormalities. Overall, 14/22 patients are alive. Spontaneous clinical remission occurred in one patient with somatic NRAS mutation, as well as two with germline PTPN11 mutations with NS-MPD, and two others with germline PTPN11 mutations and NS-MPD remain under surveillance. Patients with NS-MPD were excluded from treatment analysis as none required chemotherapeutic intervention. All patients (5/5) treated with 5-azacitidine alone and one of the four treated with 6-mercaptopurine monotherapy had a reduction in mutant variant allele frequency. Transformation to acute myeloid leukemia was seen in two patients who both died. Among patients who received transplants, 7/13 are alive, and relapse post-transplant occurred in 3/13 with a median time to relapse of 3.55 months. This report provides insight into therapy responses and long-term outcomes across different genetic subsets of JMML and lends insight into the expected time to spontaneous resolution in patients with NS-MPD with germline PTPN11 mutations.

Noonan syndrome and Noonan-like syndrome with loose anagen hair: rare phenotypes may emerge during follow-up.

Background: Noonan syndrome (NS) and Noonan-like syndrome with loose anagen hair (NS/LAH) are neurodevelopmental syndromes resulting from germline mutations in genes that participate in the rat sarcoma/mitogen-activated protein kinases (RAS/MAPK) pathway. The aim of this retrospective study was to describe common and rare manifestations of NS and NS/LAH. Methods: We collected and analyzed clinical and genetic data from 25 patients with NS and NS/LAH. Results: The patients' median age was 6.3 years (range, 1-13 years), and the male-to-female ratio was 18:7. In total, 19 patients had NS caused by a mutation in PTPN11. Another causative gene was found in six patients, including two patients with a SHOC2 mutation, one patient with a KRAS mutation, one patient with an LZTR1 mutation, one patient with a BRAF mutation, and one patient with a PPP1CB mutation. Short stature was detected in 100% of the patients. This study provides an overview of the clinical features of NS, including unique facial features, short stature, congenital heart defects, and other manifestations. Notably, systemic lupus erythematosus (SLE) was found in two SHOC2-positive patients. One patient had a posterior urethral valve, which is very rare in NS patients. Conclusions: Our study identified several clinical features that were previously poorly related to NS, including SLE. We concluded that SHOC2-related NS is associated with a particularly high risk of SLE, which may have a significant impact on quality of life, and a posterior urethral valve is a novel phenotype. These findings could be helpful in enhancing the understanding of the clinical spectrum of NS.

Phenotypic Expansion of Autosomal Dominant LZTR1-Related Disorders with Special Emphasis on Adult-Onset Features.

Leucine zipper-like transcription regulator 1 (LZTR1) acts as a negative factor that suppresses RAS function and MAPK signaling; mutations in this protein may dysregulate RAS ubiquitination and lead to impaired degradation of RAS superfamily proteins. Germline LZTR1 variants are reported in Noonan syndrome, either autosomal dominant or autosomal recessive, and in susceptibility to schwannomatosis. This article explores the genetic and phenotypic diversity of the autosomal dominant LZTR1-related disorders, compiling a cohort of previously published patients (51 with the Noonan phenotype and 123 with schwannomatosis) and presenting two additional adult-onset cases: a male with schwannomatosis and Parkinson's disease and a female with Noonan syndrome, generalized joint hypermobility, and breast cancer. This review confirms that autosomal dominant LZTR1-related disorders exhibit an extreme phenotypic variability, ranging from relatively mild manifestations to severe and multi-systemic involvement, and offers updated frequences of each clinical feature. The aim is to precisely define the clinical spectrum of LZTR1-related diseases, using also two new emblematic clinical cases. Gaining insight into the mechanisms underneath this variability is crucial to achieve precision diagnostics and the development of therapeutic interventions.

Trametinib restores the central conducting lymphatic flow in a premature infant with Noonan syndrome.

We describe a premature hydropic infant with Noonan syndrome and a therapy refractory chylothorax. This was shown to be due to a central conducting lymphatic anomaly. After therapy with a MEK-inhibitor the infant recovered clinically and radiologically completely, possibly by restoring lymphatic valve function.

Noonan Syndrome Growth Charts and Genotypes: 15-Year Longitudinal Single-Centre Study.

INTRODUCTION: Growth patterns in Noonan syndrome (NS) remain relatively unknown. The objective of this study was to provide growth reference curves for patients with NS and identify correlations between their growth, genotype, and clinical features. METHODS: This was a 15-year-long, monocentric, observational, retrospective, non-interventional study. Children with NS followed up between 2005 and 2022 at "Bambino Gesù" Children's Hospital, Italy, were included and excluded if they had received growth hormone treatment. Comparison of growth curves of participants with NS versus the general Italian population and further genotypic analyses were performed. RESULTS: Overall, 190 eligible participants with NS were identified, with median (interquartile range) age of 14.01 (9.05-19.25) years (55.8% male). Cardiovascular anomalies were present in 85.3% of participants, most commonly pulmonary stenosis (52.6%) and atrial septal defects (36.8%); 48.1% of male participants had cryptorchidism. The most frequently detected mutations were in PTPN11 (66.3%) and SOS1 (13.9%). NS sex-specific centile curves for height, weight, body mass index, and height velocity were produced. For both sexes, the 50th percentile of height and weight for participants with NS overlapped with the 3rd percentile for the general Italian population. Both sexes with a PTPN11 mutation had a significantly lower height and weight than those with "other mutations" at 5 years old. No significant associations were observed between cardiac anomalies and PTPN11 mutation status. CONCLUSION: We present longitudinal data describing growth curves and trends, the natural history, and genotypes of the NS population, which provide a useful tool for clinicians in the management of NS.