Clinical, pathological, and molecular analyses of cardiovascular abnormalities in Costello syndrome: a Ras/MAPK pathway syndrome

Dysplastic Mitral Valve in Costello Syndrome

Costello syndrome is an autosomal dominant condition caused by variants in the HRAS gene. Cardiac presentation includes valvular disease (usually valvar pulmonary stenosis), arrhythmias, and hypertrophic cardiomyopathy. To our knowledge, this is the first such report of dysplastic mitral valve associated with Costello syndrome.

The Surgical Management of Severe Scoliosis in Immature Patient with a Very Rare Disease Costello Syndrome-Clinical Example and Brief Literature Review

BACKGROUND

Costello syndrome (CS) is a rare genetic syndrome in which, due to the occurrence of a mutation in the HRAS gene on chromosome 11 that causes the manifestation, a set of features such as a characteristic appearance, many congenital defects, intellectual disability and a genetic predisposition to cancer, friendly personality, and others can be identified. CS is very rare, with an incidence of ~1/300,000, but it belongs to one of the largest groups of congenital syndromes, called RASopathies, occurring with an incidence of 1/1000 people. Scoliosis and kyphosis, as well as other spinal defects, are common, in 63% and 58% of patients, respectively, and a study conducted among adult patients showed the presence of scoliosis in 75% of patients; there may be excessive lordosis of the lumbar section and inverted curvatures of the spine (lordosis in the thoracic section and kyphosis in the lumbar section). The aim of our study is to present a case report of treatment of severe scoliosis of 130 degrees in a 14-year-old patient with Costello syndrome, with coexisting Chiari II syndrome and syrinx in the absence of skeletal maturity. This patient underwent foramen magnum decompression 3 months before planned surgical correction for severe scoliosis. The patient was qualified for surgical treatment using magnetically controlled growing rods (MCGR). After spine surgery using MCGR, we gradually performed MCGR distraction over the next 2 years; we performed the final surgery, conversion to posterior spinal fusion (PSF) with simultaneous multi-level Ponte osteotomy, which gave a very good and satisfactory surgical result. In the perioperative period, two serious complications occurred: pneumothorax caused by central catheter and gastrointestinal bleeding due to previously undiagnosed gastrointestinal varices. This case shows that the treatment of severe and neglected scoliosis is complicated and requires special preparation and a surgical plan with other cooperating specialists. The scoliosis was corrected from 130 degrees to approximately 48 degrees, sagittal balance was significantly improved, and the surgical outcome was very pleasing, significantly improving quality of life and function for the patient.

Emergence of the natural history of Myhre syndrome: 47 patients evaluated in the Massachusetts General Hospital Myhre Syndrome Clinic (2016-2023)

Myhre syndrome is an increasingly diagnosed ultrarare condition caused by recurrent germline autosomal dominant de novo variants in SMAD4. Detailed multispecialty evaluations performed at the Massachusetts General Hospital (MGH) Myhre Syndrome Clinic (2016-2023) and by collaborating specialists have facilitated deep phenotyping, genotyping and natural history analysis. Of 47 patients (four previously reported), most (81%) patients returned to MGH at least once. For patients followed for at least 5 years, symptom progression was observed in all. 55% were female and 9% were older than 18 years at diagnosis. Pathogenic variants in SMAD4 involved protein residues p.Ile500Val (49%), p.Ile500Thr (11%), p.Ile500Leu (2%), and p.Arg496Cys (38%). Individuals with the SMAD4 variant p.Arg496Cys were less likely to have hearing loss, growth restriction, and aortic hypoplasia than the other variant groups. Those with the p.Ile500Thr variant had moderate/severe aortic hypoplasia in three patients (60%), however, the small number (n = 5) prevented statistical comparison with the other variants. Two deaths reported in this cohort involved complex cardiovascular disease and airway stenosis, respectively. We provide a foundation for ongoing natural history studies and emphasize the need for evidence-based guidelines in anticipation of disease-specific therapies.

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.

HRAS-Mutant Cardiomyocyte Model of Multifocal Atrial Tachycardia

BACKGROUND

Germline HRAS gain-of-function pathogenic variants cause Costello syndrome (CS). During early childhood, 50% of patients develop multifocal atrial tachycardia, a treatment-resistant tachyarrhythmia of unknown pathogenesis. This study investigated how overactive HRAS activity triggers arrhythmogenesis in atrial-like cardiomyocytes (ACMs) derived from human-induced pluripotent stem cells bearing CS-associated HRAS variants.

METHODS

HRAS Gly12 mutations were introduced into a human-induced pluripotent stem cells-ACM reporter line. Human-induced pluripotent stem cells were generated from patients with CS exhibiting tachyarrhythmia. Calcium transients and action potentials were assessed in induced pluripotent stem cell-derived ACMs. Automated patch clamping assessed funny currents. HCN inhibitors targeted pacemaker-like activity in mutant ACMs. Transcriptomic data were analyzed via differential gene expression and gene ontology. Immunoblotting evaluated protein expression associated with calcium handling and pacemaker-nodal expression.

RESULTS

ACMs harboring HRAS variants displayed higher beating rates compared with healthy controls. The hyperpolarization activated cyclic nucleotide gated potassium channel inhibitor ivabradine and the Nav1.5 blocker flecainide significantly decreased beating rates in mutant ACMs, whereas voltage-gated calcium channel 1.2 blocker verapamil attenuated their irregularity. Electrophysiological assessment revealed an increased number of pacemaker-like cells with elevated funny current densities among mutant ACMs. Mutant ACMs demonstrated elevated gene expression (ie, ISL1, TBX3, TBX18) related to intracellular calcium homeostasis, heart rate, RAS signaling, and induction of pacemaker-nodal-like transcriptional programming. Immunoblotting confirmed increased protein levels for genes of interest and suppressed MAPK (mitogen-activated protein kinase) activity in mutant ACMs.

CONCLUSIONS

CS-associated gain-of-function HRASG12 mutations in induced pluripotent stem cells-derived ACMs trigger transcriptional changes associated with enhanced automaticity and arrhythmic activity consistent with multifocal atrial tachycardia. This is the first human-induced pluripotent stem cell model establishing the mechanistic basis for multifocal atrial tachycardia in CS.

Human Genetics of Semilunar Valve and Aortic Arch Anomalies

Lesions of the semilunar valve and the aortic arch can occur either in isolation or as part of well-described clinical syndromes. The polygenic cause of calcific aortic valve disease will be discussed including the key role of NOTCH1 mutations. In addition, the complex trait of bicuspid aortic valve disease will be outlined, both in sporadic/familial cases and in the context of associated syndromes, such as Alagille, Williams, and Kabuki syndromes. Aortic arch abnormalities particularly coarctation of the aorta and interrupted aortic arch, including their association with syndromes such as Turner and 22q11 deletion, respectively, are also discussed. Finally, the genetic basis of congenital pulmonary valve stenosis is summarized, with particular note to Ras-/mitogen-activated protein kinase (Ras/MAPK) pathway syndromes and other less common associations, such as Holt-Oram syndrome.

An Assessment of the Therapeutic Landscape for the Treatment of Heart Disease in the RASopathies

The RAS/mitogen-activated protein kinase (MAPK) pathway controls a plethora of developmental and post-developmental processes. It is now clear that mutations in the RAS-MAPK pathway cause developmental diseases collectively referred to as the RASopathies. The RASopathies include Noonan syndrome, Noonan syndrome with multiple lentigines, cardiofaciocutaneous syndrome, neurofibromatosis type 1, and Costello syndrome. RASopathy patients exhibit a wide spectrum of congenital heart defects (CHD), such as valvular abnormalities and hypertrophic cardiomyopathy (HCM). Since the cardiovascular defects are the most serious and recurrent cause of mortality in RASopathy patients, it is critical to understand the pathological signaling mechanisms that drive the disease. Therapies for the treatment of HCM and other RASopathy-associated comorbidities have yet to be fully realized. Recent developments have shown promise for the use of repurposed antineoplastic drugs that target the RAS-MAPK pathway for the treatment of RASopathy-associated HCM. However, given the impact of the RAS-MAPK pathway in post-developmental physiology, establishing safety and evaluating risk when treating children will be paramount. As such insight provided by preclinical and clinical information will be critical. This review will highlight the cardiovascular manifestations caused by the RASopathies and will discuss the emerging therapies for treatment.

A very mild phenotype in six individuals of a three-generation family with the novel HRAS variant c.176C > G p.(Ala59Gly): Emergence of a new HRAS-related RASopathy distinct from Costello syndrome

Costello syndrome is a clinically recognizable, severe neurodevelopmental disorder caused by heterozygous activating variants in HRAS. The vast majority of affected patients share recurring variants affecting HRAS codons 12 and 13 and a relatively uniform phenotype. Here, we report the unique and attenuated phenotype of six individuals of an extended family affected by the HRAS variant c.176C>T p.(Ala59Gly), which, to our knowledge, has never been reported as a germline variant in patients so far. HRAS Alanine 59 has been previously functionally investigated as an oncogenic hotspot and the p.Ala59Gly substitution was shown to impair intrinsic GTP hydrolysis. All six individuals we report share a phenotype of ectodermal anomalies and mild features suggestive of a RASopathy, reminiscent of patients with Noonan syndrome-like disorder with loose anagen hair. All six are of normal intelligence, none have a history of failure to thrive or malignancy, and they have no known cardiac or neurologic pathologies. Our report adds to the previous reports of patients with rare variants affecting amino acids located in the SWITCH II/G3 region of HRAS and suggests a consistent, attenuated phenotype distinct from classical Costello syndrome. We propose the definition of a new distinct HRAS-related RASopathy for patients carrying HRAS variants affecting codons 58, 59, 60.

A comparative analysis of RAS variants in patients with disorders of somatic mosaicism

PURPOSE

RAS genes (HRAS, KRAS, and NRAS) are commonly found to be mutated in cancers, and activating RAS variants are also found in disorders of somatic mosaicism (DoSM). A survey of the mutational spectrum of RAS variants in DoSM has not been performed.

METHODS

A total of 938 individuals with suspected DoSM underwent high-sensitivity clinical next-generation sequencing-based testing. We investigated the mutational spectrum and genotype-phenotype associations of mosaic RAS variants.

RESULTS

In this article, we present a series of individuals with DoSM with RAS variants. Classic hotspots, including Gly12, Gly13, and Gln61 constituted the majority of RAS variants observed in DoSM. Furthermore, we present 12 individuals with HRAS and KRAS in-frame duplication/insertion (dup/ins) variants in the switch II domain. Among the 18.3% individuals with RAS in-frame dup/ins variants, clinical findings were mainly associated with vascular malformations. Hotspots were associated with a broad phenotypic spectrum, including vascular tumors, vascular malformations, nevoid proliferations, segmental overgrowth, digital anomalies, and combinations of these. The median age at testing was higher and the variant allelic fraction was lower in individuals with in-frame dup/ins variants than those in individuals with mosaic RAS hotspots.

CONCLUSION

Our work provides insight into the allelic and clinical heterogeneity of mosaic RAS variants in nonmalignant conditions.

Vascular malformation rupture in a patient affected by Costello syndrome

Costello syndrome (CS) is a rare genetic syndrome affecting multiple organs, generally caused by mutations of the HRAS gene, belonging to the RAS/MAPK genes family.A male patient with CS developed a painful pulsatile mass on the lateral side of the wrist. An initial ultrasonographic investigation confirmed the presence of a radial artery lesion, possibly an arterial aneurysm. On surgical resection, histological evaluation showed a tangle of vascular structures with variable calibre and abnormal wall histology. Immunohistochemical stainings revealed a very poor endothelial contribution to the central vascular wall structure. These histological observations led us to conclude we had managed an acute vascular malformation (VM) rupture, rather than a common arterial aneurysmal condition. Considering the molecular mechanisms regulated by RAS/MAPK genes, CS patients might have a higher risk of developing VMs and, in the presence of a pulsatile mass with acute onset, VM rupture should be considered.

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.

Diagnostic yield using whole-genome sequencing and in-silico panel of 281 genes associated with non-immune hydrops fetalis in clinical setting

OBJECTIVE

To investigate the diagnostic yield of clinical whole-genome sequencing (WGS) in prenatally diagnosed non-immune hydrops fetalis (NIHF).

METHODS

This was a retrospective study of 23 fetuses with prenatally diagnosed NIHF, negative for trisomies and copy-number variants, referred for analysis by WGS with an in-silico panel of 281 genes associated with hydrops fetalis. Due to identification of a high proportion of causative variants in the HRAS gene in the main cohort, Sanger sequencing of HRAS was performed in a replication cohort, consisting of 24 additional fetuses with NIHF that were negative for trisomies and copy-number variants and had not undergone WGS.

RESULTS

Of the 23 fetuses in the main cohort, a molecular diagnosis was achieved in 12 (52.2%). Pathogenic or likely pathogenic variants were identified in seven genes: HRAS (n = 5), RIT1 (n = 2), FOXP3 (n = 1), GLB1 (n = 1), MAP2K1 (n = 1), PTPN11 (n = 1) and RASA1 (n = 1). The inheritance pattern of the 12 causative variants was autosomal dominant in 10 cases (HRAS, MAP2K1, PTPN11, RASA1, RIT1), autosomal recessive in one (GLB1) and X-linked recessive in one (FOXP3). Of the 24 fetuses in the replication cohort, a pathogenic variant in HRAS was identified in one, resulting in an overall frequency of causative HRAS variants of 12.8% (6/47) in our two cohorts.

CONCLUSIONS

We demonstrate a diagnostic yield of 52% with clinical WGS in NIHF using an in-silico panel of 281 genes. However, the high diagnostic yield may be attributed to the small sample size and possible over-representation of severe phenotypes in the included fetuses. Bearing in mind that chromosomal abnormalities were excluded in our cohorts, a detection rate of up to 75% is possible in prenatally diagnosed NIHF when WGS analysis includes calling of chromosomal aberrations. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Rapid Weight Loss and Severe Failure to Thrive Mimicking Lipodystrophy Syndrome in a 1-Year-Old Taiwanese Girl with Costello Syndrome

Costello syndrome (CS) is a type of RASopathy caused mainly by de-novo heterozygous pathogenic variants in the HRAS gene located on chromosome 11p15.5. The phenotype of CS is characterized by prenatal overgrowth, postnatal failure to thrive, curly or sparse fine hair, coarse facial features, and multisystem involvement, including cardiovascular, endocrine, and gastroenterological disorders. We present a one-year-old girl with rapid weight loss and severe failure to thrive. She had gastroesophageal reflux at the age of four months with subsequent rapid weight loss. The loss of fat tissue over the whole body, refractory to a hypercaloric diet, mimicked the presentation of progressive lipodystrophy and masked the dysmorphic features of CS. The final diagnosis of CS was made by whole exome sequencing, which demonstrated a hot-spot, heterozygouspathogenic variant in the HRAS gene (c.34G > A, rs104894229). Our patient illustrates that the excessive energy needs in CS patients may lead to severe failure to thrive and cause challenges in diagnosing CS. This case also highlights the importance of recognizing CS in patients with a history of prenatal overgrowth, polyhydramnios presenting with severe failure to thrive refractory to pharmacotherapy and tube feeding.

Multidisciplinary Management of Costello Syndrome: Current Perspectives

Costello syndrome (CS) is a rare neurodevelopmental disorder caused by germline mutations in HRAS. It belongs among the RASopathies, a group of syndromes characterized by alterations in components of the RAS/MAPK signaling pathway and sharing overlapping phenotypes. Its typical features include a distinctive facial appearance, growth delay, intellectual disability, ectodermal, cardiac, and musculoskeletal abnormalities, and cancer predisposition. Due to the several comorbidities having a strong impact on the quality of life, a multidisciplinary team is essential in the management of such a condition from infancy to adult age, to promptly address any detected issue and to develop appropriate personalized follow-up protocols and treatment strategies. With the present paper we aim to highlight the core and ancillary medical disciplines involved in managing the health challenges characterizing CS from pediatric to adult age, according to literature and to our large clinical experience.

HRAS germline mutations impair LKB1/AMPK signaling and mitochondrial homeostasis in Costello syndrome models

Germline mutations that activate genes in the canonical RAS/MAPK signaling pathway are responsible for rare human developmental disorders known as RASopathies. Here, we analyzed the molecular determinants of Costello syndrome (CS) using a mouse model expressing HRAS p.G12S, patient skin fibroblasts, hiPSC-derived human cardiomyocytes, a HRAS p.G12V zebrafish model and human fibroblasts expressing lentiviral constructs carrying HRAS p.G12S or HRAS p.G12A mutations. The findings revealed alteration of mitochondrial proteostasis and defective oxidative phosphorylation in the heart and skeletal muscle of Costello mice that were also found in the cell models of the disease. The underpinning mechanisms involved the inhibition of the AMPK signaling pathway by mutant forms of HRAS, leading to alteration of mitochondrial proteostasis and bioenergetics. Pharmacological activation of mitochondrial bioenergetics and quality control restored organelle function in HRAS p.G12A and p.G12S cell models, reduced left ventricle hypertrophy in the CS mice and diminished the occurrence of developmental defects in the CS zebrafish model. Collectively, these findings highlight the importance of mitochondrial proteostasis in the pathophysiology of RASopathies and suggest that patients with Costello syndrome may benefit from treatment with mitochondrial modulators.

The RASopathies: from pathogenetics to therapeutics

The RASopathies are a group of disorders caused by a germline mutation in one of the genes encoding a component of the RAS/MAPK pathway. These disorders, including neurofibromatosis type 1, Noonan syndrome, cardiofaciocutaneous syndrome, Costello syndrome and Legius syndrome, among others, have overlapping clinical features due to RAS/MAPK dysfunction. Although several of the RASopathies are very rare, collectively, these disorders are relatively common. In this Review, we discuss the pathogenesis of the RASopathy-associated genetic variants and the knowledge gained about RAS/MAPK signaling that resulted from studying RASopathies. We also describe the cell and animal models of the RASopathies and explore emerging RASopathy genes. Preclinical and clinical experiences with targeted agents as therapeutics for RASopathies are also discussed. Finally, we review how the recently developed drugs targeting RAS/MAPK-driven malignancies, such as inhibitors of RAS activation, direct RAS inhibitors and RAS/MAPK pathway inhibitors, might be leveraged for patients with RASopathies.

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.

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.

Genetics of congenital heart disease: a narrative review of recent advances and clinical implications

Congenital heart disease (CHD) is the most common human birth defect and remains a leading cause of mortality in childhood. Although advances in clinical management have improved the survival of children with CHD, adult survivors commonly experience cardiac and non-cardiac comorbidities, which affect quality of life and prognosis. Therefore, the elucidation of genetic etiologies of CHD not only has important clinical implications for genetic counseling of patients and families but may also impact clinical outcomes by identifying at-risk patients. Recent advancements in genetic technologies, including massively parallel sequencing, have allowed for the discovery of new genetic etiologies for CHD. Although variant prioritization and interpretation of pathogenicity remain challenges in the field of CHD genomics, advances in single-cell genomics and functional genomics using cellular and animal models of CHD have the potential to provide novel insights into the underlying mechanisms of CHD and its associated morbidities. In this review, we provide an updated summary of the established genetic contributors to CHD and discuss recent advances in our understanding of the genetic architecture of CHD along with current challenges with the interpretation of genetic variation. Furthermore, we highlight the clinical implications of genetic findings to predict and potentially improve clinical outcomes in patients with CHD.

Molecules linked to Ras signaling as therapeutic targets in cardiac pathologies

Abstract

The Ras family of small Guanosine Triphosphate (GTP)-binding proteins (G proteins) represents one of the main components of intracellular signal transduction required for normal cardiac growth, but is also critically involved in the development of cardiac hypertrophy and heart failure. The present review provides an update on the role of the H-, K- and N-Ras genes and their related pathways in cardiac diseases. We focus on cardiac hypertrophy and heart failure, where Ras has been studied the most. We also review other cardiac diseases, like genetic disorders related to Ras. The scope of the review extends from fundamental concepts to therapeutic applications. Although the three Ras genes have a nearly identical primary structure, there are important functional differences between them: H-Ras mainly regulates cardiomyocyte size, whereas K-Ras regulates cardiomyocyte proliferation. N-Ras is the least studied in cardiac cells and is less associated to cardiac defects. Clinically, oncogenic H-Ras causes Costello syndrome and facio-cutaneous-skeletal syndromes with hypertrophic cardiomyopathy and arrhythmias. On the other hand, oncogenic K-Ras and alterations of other genes of the Ras-Mitogen-Activated Protein Kinase (MAPK) pathway, like Raf, cause Noonan syndrome and cardio-facio-cutaneous syndromes characterized by cardiac hypertrophy and septal defects. We further review the modulation by Ras of key signaling pathways in the cardiomyocyte, including: (i) the classical Ras-Raf-MAPK pathway, which leads to a more physiological form of cardiac hypertrophy; as well as other pathways associated with pathological cardiac hypertrophy, like (ii) The SAPK (stress activated protein kinase) pathways p38 and JNK; and (iii) The alternative pathway Raf-Calcineurin-Nuclear Factor of Activated T cells (NFAT). Genetic alterations of Ras isoforms or of genes in the Ras-MAPK pathway result in Ras-opathies, conditions frequently associated with cardiac hypertrophy or septal defects among other cardiac diseases. Several studies underline the potential role of H- and K-Ras as a hinge between physiological and pathological cardiac hypertrophy, and as potential therapeutic targets in cardiac hypertrophy and failure.

Graphic abstract

The Ras (Rat Sarcoma) gene family is a group of small G proteins

Ras is regulated by growth factors and neurohormones affecting cardiomyocyte growth and hypertrophy

Ras directly affects cardiomyocyte physiological and pathological hypertrophy

Genetic alterations of Ras and its pathways result in various cardiac phenotypes

Ras and its pathway are differentially regulated in acquired heart disease

Ras modulation is a promising therapeutic target in various cardiac conditions.

Costello syndrome with special cutaneous manifestations and HRAS G12D mutation: A case report and literature review

Background

Costello syndrome (CS, OMIM 218040) is a rare congenital disorder caused by mutations in HRAS. Previous studies reported that approximately 80% of patients with CS share the same pathogenic variant in HRAS gene in c.34G> A (p.G12S). Here, we report a CS patient with c.34G> A (p.G12D) variant in HRAS gene and she presented with special manifestation.

Methods and Results

We describe a 31‐year‐old female patient who presented with distinctive facial appearance, intellectual disability, dental abnormalities, hyperkeratosis of palmer and planter, loose skin at birth, papillomata on the face and nipples. The whole‐exome sequencing (WES) technology provided by Haotian Biotechnology (China) confirmed p.G12D variant in HRAS gene. To elucidate the typical features of CS with p.G12D variant, we further reviewed these previously reported cases and found that patients with G12D variant died within three months after birth due to multiple organ failure. They had the typical facial characteristics, failure to thrive, skin and cardiac abnormalities, and gene testing confirmed the diagnosis of CS.

Conclusion

To the best of our knowledge, this is the first article to report a patient with a p.G12D variant that had special but mild manifestation. Moreover, this report and literature review casts new light on the clinical features of p.G12D variant.

Congenital polyvalvular disease expands the cardiac phenotype of the RASopathies

The RASopathies are a group of similar genetic syndromes with cardiovascular abnormalities, characteristic facial features, short stature, abnormalities of the skin and musculoskeletal system, and variable neurodevelopmental challenges. The most common cardiovascular abnormalities include pulmonary valvular stenosis and hypertrophic cardiomyopathy. Congenital polyvalvular disease (CPVD) refers to congenital dysplasia of two or more cardiac valves. We diagnosed a RASopathy in two individuals with CPVD and noted that CPVD in RASopathies has rarely been reported in the literature. Thus, we performed a retrospective chart review and literature review to investigate the association and characterize the phenotype of CPVD in the RASopathies. CPVD was present in 2.5% (n = 6/243) of individuals in our RASopathy cohort. Involvement of two cardiac valves, commonly the aortic and pulmonic valves, was seen in the majority of individuals (6/8; 75%) in our cohort, but only 27% (3/11) of reported CPVD and RASopathy cases in the literature. CPVD should be considered an associated cardiovascular phenotype of the RASopathies, which has implications for diagnosis and management.

Hypertrophic Cardiomyopathy in Children: Pathophysiology, Diagnosis, and Treatment of Non-sarcomeric Causes

Hypertrophic cardiomyopathy (HCM) is a myocardial disease characterized by left ventricular hypertrophy not solely explained by abnormal loading conditions. Despite its rare prevalence in pediatric age, HCM carries a relevant risk of mortality and morbidity in both infants and children. Pediatric HCM is a large heterogeneous group of disorders. Other than mutations in sarcomeric genes, which represent the most important cause of HCM in adults, childhood HCM includes a high prevalence of non-sarcomeric causes, including inherited errors of metabolism (i.e., glycogen storage diseases, lysosomal storage diseases, and fatty acid oxidation disorders), malformation syndromes, neuromuscular diseases, and mitochondrial disease, which globally represent up to 35% of children with HCM. The age of presentation and the underlying etiology significantly impact the prognosis of children with HCM. Moreover, in recent years, different targeted approaches for non-sarcomeric etiologies of HCM have emerged. Therefore, the etiological diagnosis is a fundamental step in designing specific management and therapy in these subjects. The present review aims to provide an overview of the non-sarcomeric causes of HCM in children, focusing on the pathophysiology, clinical features, diagnosis, and treatment of these rare disorders.

Genetic Basis of Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common major congenital anomaly with an incidence of ∼1% of live births and is a significant cause of birth defect-related mortality. The genetic mechanisms underlying the development of CHD are complex and remain incompletely understood. Known genetic causes include all classes of genetic variation including chromosomal aneuploidies, copy number variants, and rare and common single-nucleotide variants, which can be either de novo or inherited. Among patients with CHD, ∼8%-12% have a chromosomal abnormality or aneuploidy, between 3% and 25% have a copy number variation, and 3%-5% have a single-gene defect in an established CHD gene with higher likelihood of identifying a genetic cause in patients with nonisolated CHD. These genetic variants disrupt or alter genes that play an important role in normal cardiac development and in some cases have pleiotropic effects on other organs. This work reviews some of the most common genetic causes of CHD as well as what is currently known about the underlying mechanisms.

Germline and sporadic cancers driven by the RAS pathway: parallels and contrasts

Somatic mutations in RAS and related pathway genes such as NF1 have been strongly implicated in the development of cancer while also being implicated in a diverse group of developmental disorders named the 'RASopathies', including neurofibromatosis type 1 (NF1), Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NSML), Costello syndrome (CS), cardiofaciocutaneous syndrome (CFC), and capillary malformation-arteriovenous syndrome (CM-AVM). It remains unclear why (i) there is little overlap in mutational subtype between Ras-driven malignancies associated with sporadic disease and those associated with the RASopathy syndromes, and (ii) RASopathy-associated cancers are usually of different histological origin to those seen with sporadic mutations of the same genes. For instance, germline variants in KRAS and NRAS are rarely found at codons 12, 13 or 61, the most common sites for somatic mutations in sporadic cancers. An exception is CS, where germline variants in codons 12 and 13 of HRAS occur relatively frequently. Given recent renewed drug interest following early clinical success of RAS G12C and farnesyl transferase inhibitors, an improved understanding of this relationship could help guide targeted therapies for both sporadic and germline cancers associated with the Ras pathway.

Advancing RAS/RASopathy therapies: An NCI-sponsored intramural and extramural collaboration for the study of RASopathies

RASopathies caused by germline pathogenic variants in genes that encode RAS pathway proteins. These disorders include neurofibromatosis type 1 (NF1), Noonan syndrome (NS), cardiofaciocutaneous syndrome (CFC), and Costello syndrome (CS), and others. RASopathies are characterized by heterogenous manifestations, including congenital heart disease, failure to thrive, and increased risk of cancers. Previous work led by the NCI Pediatric Oncology Branch has altered the natural course of one of the key manifestations of the RASopathy NF1. Through the conduct of a longitudinal cohort study and early phase clinical trials, the MEK inhibitor selumetinib was identified as the first active therapy for the NF1-related peripheral nerve sheath tumors called plexiform neurofibromas (PNs). As a result, selumetinib was granted breakthrough therapy designation by the FDA for the treatment of PN. Other RASopathy manifestations may also benefit from RAS targeted therapies. The overall goal of Advancing RAS/RASopathy Therapies (ART), a new NCI initiative, is to develop effective therapies and prevention strategies for the clinical manifestations of the non-NF1 RASopathies and for tumors characterized by somatic RAS mutations. This report reflects discussions from a February 2019 initiation meeting for this project, which had broad international collaboration from basic and clinical researchers and patient advocates.

The impact of RASopathy-associated mutations on CNS development in mice and humans

The RAS signaling pathway is involved in the regulation of developmental processes, including cell growth, proliferation, and differentiation, in the central nervous system (CNS). Germline mutations in the RAS signaling pathway genes are associated with a group of neurodevelopmental disorders, collectively called RASopathy, which includes neurofibromatosis type 1, Noonan syndrome, cardio-facio-cutaneous syndrome, and Costello syndrome. Most mutations associated with RASopathies increase the activity of the RAS-ERK signaling pathway, and therefore, most individuals with RASopathies share common phenotypes, such as a short stature, heart defects, facial abnormalities, and cognitive impairments, which are often accompanied by abnormal CNS development. Recent studies using mouse models of RASopathies demonstrated that particular mutations associated with each disorder disrupt CNS development in a mutation-specific manner. Here, we reviewed the recent literatures that investigated the developmental role of RASopathy-associated mutations using mutant mice, which provided insights into the specific contribution of RAS-ERK signaling molecules to CNS development and the subsequent impact on cognitive function in adult mice.

Medically actionable comorbidities in adults with Costello syndrome

Costello syndrome (CS) is an autosomal-dominant condition caused by activating missense mutations in HRAS. There is little literature describing health concerns specific to adults with CS. Parents of individuals with CS need to know what to anticipate as their children age. We surveyed a group of 20 adults and older adolescents with CS regarding their medical concerns and lifestyle characteristics. We identified several previously undescribed actionable medical concerns in adults with CS. First, the high prevalence of anxiety in this cohort indicates that screening for anxiety is warranted since this is a treatable condition that can have a significant impact on quality of life. Second, adults with CS should be monitored for progressive contractures or other problems that could decrease mobility. This is especially important in a population that seems to have increased risk for osteopenia. Finally, the lack of cancer diagnoses in adulthood is of interest, although the cohort is too small to draw definitive conclusions about cancer risk in adults with CS. Ongoing follow-up of the current cohort of adults with CS is necessary to delineate progressive medical and physical problems, which is essential for providing targeted management recommendations and anticipatory guidance to families.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Phenotypic and Genetic Characteristics of Five Korean Patients with Costello Syndrome

Costello syndrome (CS) is a rare genetic disorder characterized by distinctive facial appearance, cardiopulmonary complications, severe growth retardation, skin and skeletal defects, developmental delay, and tumor predisposition. CS is caused by heterozygous de novo mutations in the proto-oncogene HRAS, which is a component of the RAS/mitogen-activated protein kinase pathway. Herein, we reviewed the phenotypic and genetic features of 5 Korean patients who were genetically diagnosed with CS. Atrial tachycardia and polyhydramnios, which are important prenatal features for CS, were observed in 4 and 5 patients, respectively. The distinctive coarse facial appearances of the patients and presence of deep palmoplantar creases supported the clinical diagnosis of CS, which was confirmed by HRAS sequence analysis. Extremely poor postnatal growth was observed in all 5 patients. Further, all patients exhibited cardiac abnormalities; left ventricular hypertrophy and hypertrophic cardiomyopathy were observed in 3 patients. All 5 patients suffered from airway problems; 3 of them required intubation right after birth, and 2 of them received tracheostomy. One patient with a p.Gly12Ser mutation was diagnosed with retroperitoneal rhabdomyosarcoma alveolar type at the age of 5 years. Consistent with previous reports, both patients with p.Gly12Cys mutations died within the first year of life due to cardiopulmonary failure. Our study summarizes the characteristics of these 5 Korean patients with CS and, along with previous studies, provides clues for genotype-phenotype correlation in patients with CS.

Costello syndrome: Clinical phenotype, genotype, and management guidelines

Costello syndrome (CS) is a RASopathy caused by activating germline mutations in HRAS. Due to ubiquitous HRAS gene expression, CS affects multiple organ systems and individuals are predisposed to cancer. Individuals with CS may have distinctive craniofacial features, cardiac anomalies, growth and developmental delays, as well as dermatological, orthopedic, ocular, and neurological issues; however, considerable overlap with other RASopathies exists. Medical evaluation requires an understanding of the multifaceted phenotype. Subspecialists may have limited experience in caring for these individuals because of the rarity of CS. Furthermore, the phenotypic presentation may vary with the underlying genotype. These guidelines were developed by an interdisciplinary team of experts in order to encourage timely health care practices and provide medical management guidelines for the primary and specialty care provider, as well as for the families and affected individuals across their lifespan. These guidelines are based on expert opinion and do not represent evidence-based guidelines due to the lack of data for this rare condition.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Cardiovascular disease in Noonan syndrome

PURPOSE OF REVIEW

To provide information on the scope of cardiac disease in Noonan syndrome.

RECENT FINDINGS

Noonan syndrome is a common autosomal dominant RASopathy disorder characterized by clinical findings of facial dysmorphism, congenital heart disease, and short stature. The degree of genetic heterogeneity has recently become evident in that Noonan syndrome is now known to be caused by mutations in a large variety of genes which produce dysregulation of the RAS-MAPK (mitogen-activated protein kinase) signaling pathway. The scope of cardiac disease in Noonan syndrome is quite variable depending on the gene mutation, with some mutations usually associated with a high incidence of congenital heart defects (PTPN11, KRAS, and others) while those with predominantly hypertrophic cardiomyopathy (HCM) have higher risk and morbidity profiles (RAF1, RIT1, and those associated with multiple lentigines).

SUMMARY

Cardiac disease in Noonan syndrome varies according to the type of gene mutation. The most common forms of cardiac disease include pulmonary stenosis, HCM, and atrial septal defect. HCM in general is associated with increased risk, mortality, and morbidity. New concepts for potential treatments are discussed.

Nonreentrant atrial tachycardia occurs independently of hypertrophic cardiomyopathy in RASopathy patients

Multifocal atrial tachycardia (MAT) has a well-known association with Costello syndrome, but is rarely described with related RAS/MAPK pathway disorders (RASopathies). We report 11 patients with RASopathies (Costello, Noonan, and Noonan syndrome with multiple lentigines [formerly LEOPARD syndrome]) and nonreentrant atrial tachycardias (MAT and ectopic atrial tachycardia) demonstrating overlap in cardiac arrhythmia phenotype. Similar overlap is seen in RASopathies with respect to skeletal, musculoskeletal and cutaneous abnormalities, dysmorphic facial features, and neurodevelopmental deficits. Nonreentrant atrial tachycardias may cause cardiac compromise if sinus rhythm is not restored expeditiously. Typical first-line supraventricular tachycardia anti-arrhythmics (propranolol and digoxin) were generally not effective in restoring or maintaining sinus rhythm in this cohort, while flecainide or amiodarone alone or in concert with propranolol were effective anti-arrhythmic agents for acute and chronic use. Atrial tachycardia resolved in all patients. However, a 4-month-old boy from the cohort was found asystolic (with concurrent cellulitis) and a second patient underwent cardiac transplant for heart failure complicated by recalcitrant atrial arrhythmia. While propranolol alone frequently failed to convert or maintain sinus rhythm, fleccainide or amiodarone, occasionally in combination with propranolol, was effective for RASopathy patient treatment for nonreentrant atrial arrhythmia. Our analysis shows that RASopathy patients may have nonreentrant atrial tachycardia with and without associated cardiac hypertrophy. While nonreentrant arrhythmia has been traditionally associated with Costello syndrome, this work provides an expanded view of RASopathy cardiac arrhythmia phenotype as we demonstrate mutant proteins throughout this signaling pathway can also give rise to ectopic and/or MAT.

RAS signalling in energy metabolism and rare human diseases

The RAS pathway is a highly conserved cascade of protein-protein interactions and phosphorylation that is at the heart of signalling networks that govern proliferation, differentiation and cell survival. Recent findings indicate that the RAS pathway plays a role in the regulation of energy metabolism via the control of mitochondrial form and function but little is known on the participation of this effect in RAS-related rare human genetic diseases. Germline mutations that hyperactivate the RAS pathway have been discovered and linked to human developmental disorders that are known as RASopathies. Individuals with RASopathies, which are estimated to affect approximately 1/1000 human birth, share many overlapping characteristics, including cardiac malformations, short stature, neurocognitive impairment, craniofacial dysmorphy, cutaneous, musculoskeletal, and ocular abnormalities, hypotonia and a predisposition to developing cancer. Since the identification of the first RASopathy, type 1 neurofibromatosis (NF1), which is caused by the inactivation of neurofibromin 1, several other syndromes have been associated with mutations in the core components of the RAS-MAPK pathway. These syndromes include Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NSML), which was formerly called LEOPARD syndrome, Costello syndrome (CS), cardio-facio-cutaneous syndrome (CFC), Legius syndrome (LS) and capillary malformation-arteriovenous malformation syndrome (CM-AVM). Here, we review current knowledge about the bioenergetics of the RASopathies and discuss the molecular control of energy homeostasis and mitochondrial physiology by the RAS pathway.

Clinical Presentation and Natural History of Hypertrophic Cardiomyopathy in RASopathies

RASopathies are a heterogeneous group of genetic syndromes characterized by mutations in genes that regulate cellular processes, including proliferation, differentiation, survival, migration, and metabolism. Excluding congenital heart defects, hypertrophic cardiomyopathy is the most frequent cardiovascular defect in patients affected by RASopathies. A worse outcome (in terms of surgical risk and/or mortality) has been described in a specific subset of Rasopathy patients with early onset, severe hypertrophic cardiomyopathy presenting with heart failure. New short-term therapy with a mammalian target of rapamycin inhibitor has recently been used to prevent heart failure in these patients with a severe form of hypertrophic cardiomyopathy.

The Complexity of Pediatric Multifocal Atrial Tachycardia and Its Prognostic Factors

Background and Objectives

Multifocal atrial tachycardia (MAT), in general, has a favorable outcome. However, there are insufficient data regarding MAT in a pediatric population. This study sought to determine the clinical course of MAT and identify potential prognostic factors.

Methods

The medical records of MAT patients from 1997–2015 were reviewed. The arrhythmia control rate and factors for unfavorable outcomes were assessed and compared to those in the literature.

Results

Of the 33 included patients (19 boys and 14 girls), 27 were infants less than 1 year of age. The median age at diagnosis was 1.7 months (range, 0 day to 14 years). Fourteen (42%) patients had structural heart disease. Eight (24%) patients had lung disease and 6 (18%) had a syndromic diagnosis belonging to RASopathy. Two patients developed polymorphic ventricular tachycardia, in whom genetic analysis confirmed the presence of the RyR2 mutation several years later. MAT was controlled in 26 patients (84%) within 3.9 months (median; range, 16 days–18.4 years) using an average of 2.4 medications. There were 3 cases of cardiopulmonary mortality. The arrhythmia control rate was higher in the infant group (85%) than in the non-infant group (67%), although this trend was not statistically significant. There was a significantly lower rate of unfavorable outcomes in the idiopathic infant group (n=11) than in the other groups (p=0.008). Considering the findings of previous studies, the mortality rate was significantly higher in patients with structural heart disease than in patients without (21% vs. 5%, p=0.01).

Conclusions

MAT usually affects infants and has a favorable prognosis, particularly in the idiopathic infant group. However, in the presence of other comorbidities, MAT may have a variable clinical course.

A novel patient with an attenuated Costello syndrome phenotype due to an HRAS mutation affecting codon 146-Literature review and update

De novo germline mutations in HRAS cause Costello syndrome, with >95% of the mutations causing Costello syndrome affecting amino acid position 12 (p.Gly12) or 13 (p.Gly13). We report on a patient with de novo missense mutation causing an amino acid change at codon 146 of HRAS, c.436G > C:p.Ala146Pro, who presented with subtle dysmorphic features, failure to thrive, global developmental delay, and hypertrophic obstructive cardiomyopathy. Mutations affecting codon 146 are observed in <1% of patients with Costello syndrome. From literature search, there were only two other patients reported with mutations involving the same location. We summarized and updated their findings, and discussed evidence to show that these patients with less obvious signs of Costello syndrome may not necessarily run a more benign clinical course.

Cardiac defects, morbidity and mortality in patients affected by RASopathies. CARNET study results

BACKGROUND

RASopathies are developmental disease caused by mutations in genes encoding for signal transducers of the RAS-MAPK cascade. The aim of the present study was to provide a comprehensive description of morbidity and mortality in patients with molecularly confirmed RASopathy.

METHODS

A multicentric, observational, retrospective study was conducted in seven European cardiac centres participating to the CArdiac Rasopathy NETwork (CARNET). Clinical records of 371 patients with confirmed molecular diagnosis of RASopathy were reviewed. Mortality was described as crude mortality, cumulative survival and restricted estimated mean survival. Multivariable regression analysis was used to assess the impact of mutated genes on number of interventions and overall prognosis.

RESULTS

Cardiac defects occurred in 80.3% of cases, almost half of them underwent at least one intervention. Overall, crude mortality was 0.29/100 patients-year. Cumulative survival was 98.8%, 98.2%, 97.7%, 94.3%, at 1, 5, 10, and 20years, respectively. Restricted estimated mean survival at 20years follow-up was 19.6years. Ten patients died (2.7% of the entire cohort; 3.4% of patients with cardiac defect). Patients with hypertrophic cardiomyopathy (HCM) and age <2years or young adults, as well as subjects with biventricular obstruction and PTPN11 mutations had a higher risk of cardiac death.

CONCLUSIONS

The risk of intervention was higher in individuals with Noonan syndrome and pulmonary stenosis carrying PTPN11 mutations. Overall, mortality was relatively low, even though the specific association between HCM, biventricular outflow tract obstructions and PTPN11 mutations appeared to be associated with early mortality, including immediate post-operative events and sudden death.

A comparison of the functional health of children with Costello syndrome in 1999 and in 2015

Costello Syndrome is a rare congenital condition characterized by failure-to-thrive, cardiac abnormalities, distinctive facial features, predisposition to malignant tumors, and developmental delay. In 1999, we analyzed the functional health in a cohort of 18 patients. Since then, a mutation in the HRAS gene has been found to be causative, medical management has been refined, and the level of awareness has increased. The purpose of this study is to compare the functional health outcomes from the 1999 cohort with data prospectively collected from a comparable cohort in 2015. The Pediatric Outcome Data Collection Instrument (PODCI) was administered to parents of children with Costello syndrome during the 2015 International Costello Syndrome Conference. The same instrument and setting were used in the 1999 study. We compared functional health scores from the two groups. A total of 21 participants were included in the 2015 cohort; 15 females (71%) and 6 males (29%). Average age was 5.8 years (range 2-16). When comparing functional health outcomes, we found that the 2015 cohort scored slightly higher in Upper Extremity and Physical Function (57 vs. 54) and Comfort scales (86 vs. 82). However, there was no significant difference in any of the PODCI scales between the two groups. When compared with normative scores, both groups scored significantly lower in every scale except for happiness (p = 0.2952). Despite recent advancements, functional health outcomes in 2015 were similar to those measured in a different cohort in 1999.

Novel pathogenic variant in the HRAS gene with lethal outcome and a broad phenotypic spectrum among Polish patients with Costello syndrome

Costello syndrome (CS) is a rare congenital disorder from the group of RASopathies, characterized by a distinctive facial appearance, failure to thrive, cardiac and skin anomalies, intellectual disability, and a predisposition to neoplasia. CS is associated with germline mutations in the proto-oncogene HRAS, a small GTPase from the Ras family. In this study, a molecular and clinical analysis was carried out in eight Polish patients with the Costello phenotype. A molecular test showed two known heterozygous mutations in the first coding exon of the gene in seven patients: p.G12S (n=4) and p.G12A (n=3), and a novel pathogenic variant p.G60V in one child with an unusually severe, lethal course of the syndrome. In addition, a fatal course of CS was present in one patient with the p.G12A mutation and in another with p.G12S, there was a co-occurrence of Turner syndrome because of the distal Xp deletion. A severe clinical manifestation with a lethal outcome in an individual with p.G60V in HRAS and contrary observations of an attenuated phenotype in CS patients with other mutations at glycine-60 residue may suggest that the nature of the substituted amino acid plays a significant role in the clinical variability observed in some CS cases.

Protection against death and renal failure by renin-angiotensin system blockers in patients with diabetes and kidney disease

INTRODUCTION

Angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) are widely used to block the renin-angiotensin system (RAS). Yet it remains uncertain whether these drugs are equally effective and safe.

METHODS

Systematic reviews and meta-analyses of ACEis/ARBs in diabetes and kidney disease published in PubMed, Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases were searched for clinical outcomes including all-cause mortality, end-stage renal disease (ESRD), hyperkalemia and cough.

RESULTS

Eight meta-analyses included 2177-61,264 patients with follow-up of 6-108 months. RAS blockers reduced mortality (relative risk ratio (RR), 0.90, 95% confidence interval (CI), 0.86-0.95) without heterogeneity. The death protection was significant specifically with ACEis (RR, 0.85, 95% CI, 0.79-0.91), but not with ARBs. Protection against ESRD was homogenously evident by ARBs (RR, 0.79, 95% CI, 0.73-0.87), ACEis (RR, 0.79, 95% , 0.64-0.94), and both (RR, 0.79, 95% CI, 0.73-0.87). Significant side effects were hyperkalemia by ARBs (RR, 2.44, 95% CI, 1.13-5.26), and cough by ACEis (RR, 2.38, 95% CI, 1.75-3.22) CONCLUSIONS: In patients with diabetes and kidney disease, ACEis and ARBs are consistently protective for the development of ESRD. Use of ACEis alone additionally reduces deaths and increases the risk for cough. Use of ARBs alone increases the risk for hyperkalemia without additional benefit of death protection.

Gain-of-function mutations in SMAD4 cause a distinctive repertoire of cardiovascular phenotypes in patients with Myhre syndrome

Myhre syndrome is a rare, distinctive syndrome due to specific gain-of-function mutations in SMAD4. The characteristic phenotype includes short stature, dysmorphic facial features, hearing loss, laryngotracheal anomalies, arthropathy, radiographic defects, intellectual disability, and a more recently appreciated spectrum of cardiovascular defects with a striking fibroproliferative response to surgical intervention. We report four newly described patients with typical features of Myhre syndrome who had (i) a mildly narrow descending aorta and restrictive cardiomyopathy; (ii) recurrent pericardial and pleural effusions; (iii) a large persistent ductus arteriosus with juxtaductal aortic coarctation; and (iv) restrictive pericardial disease requiring pericardiectomy. Additional information is provided about a fifth previously reported patient with fatal pericardial disease. A literature review of the cardiovascular features of Myhre syndrome was performed on 54 total patients, all with a SMAD4 mutation. Seventy percent had a cardiovascular abnormality including congenital heart defects (63%), pericardial disease (17%), restrictive cardiomyopathy (9%), and systemic hypertension (15%). Pericarditis and restrictive cardiomyopathy are associated with high mortality (three patients each among 10 deaths); one patient with restrictive cardiomyopathy also had epicarditis. Cardiomyopathy and pericardial abnormalities distinguish Myhre syndrome from other disorders caused by mutations in the TGF-β signaling cascade (Marfan, Loeys-Dietz, or Shprintzen-Goldberg syndromes). We hypothesize that the expanded spectrum of cardiovascular abnormalities relates to the ability of the SMAD4 protein to integrate diverse signaling pathways, including canonical TGF-β, BMP, and Activin signaling. The co-occurrence of congenital and acquired phenotypes demonstrates that the gene product of SMAD4 is required for both developmental and postnatal cardiovascular homeostasis. © 2016 Wiley Periodicals, Inc.