MEK Inhibition for RASopathy-Associated Hypertrophic Cardiomyopathy: Clinical Application of a Basic Concept.

The term "RASopathies" designates a group of developmental syndromes that are caused by activating variants of the rat sarcoma virus protein (RAS)/mitogen-activated protein kinase (MAPK) cascade. The most prevalent clinical diagnosis is Noonan syndrome, and other, less prevalent conditions include Noonan syndrome with multiple lentigines, Costello syndrome, cardiofaciocutaneous syndrome, and others. Hypertrophic cardiomyopathy occurs in 10% of these patients and can be severe and life-threating. Recently, repurposing of medications inhibiting the RAS/MAPK on a compassionate use basis has emerged as a promising concept to improve the outcome of these patients. Herein, we specifically review the role of the RAS/MAPK pathway in RASopathy-associated cardiomyopathy, and discuss the role of small-molecule inhibition in the treatment of this condition. We describe how drug repurposing of trametinib (mitogen-activated protein/extracellular signal-regulated kinase inhibition) and sirolimus/everolimus (mammalian target of rapamycin inhibition) was performed, how genotype-specific therapies are chosen and followed, as well as initial outcomes from early case series. Finally, we lay out the challenges and opportunities for trials that aim to quantify the benefits of this approach.

Fatal leukodystrophy in Costello syndrome: a case report.

BACKGROUND: Costello syndrome (CS) is a rare genetic condition characterized by dysregulation of the signaling pathway, phenotypic alteration due to fetal macrosomia or growth retardation, facial abnormalities, loose skin, cardiovascular abnormalities, and a variable degree of intellectual disability. CASE PRESENTATION: We describe the case of a 20-month-old male patient with fetal macrosomia and polyhydramnios, presenting psychomotor development delay and growth limitation during the first months of life. CS was diagnosed at four months of age after detecting a variant of the HRAS gene c.35G > C (p.G12A). A clinical description of his condition was recorded throughout his life, including cardiovascular diseases, endocrine disorders, and recurrent infections. At 20 months of age, after presenting events of marked hypotonia and generalized seizures, brain magnetic resonance revealed symmetrical lesions of the infra- and supratentorial white matter in both cerebral hemispheres, which resulted in the diagnosis of cerebral leukodystrophy. The patient had a rapid and progressive deterioration that eventually led to death. CONCLUSIONS: This is the first report of a case of CS in Peru. In addition, this is a case that presented with multisystemic conditions culminating in leukodystrophy, which is a rare event according to the literature.

Dermatological manifestations, management, and care in RASopathies.

RASopathies are rare genetic disorders caused by germline pathogenic variants in genes belonging to the RAS/MAPK pathway, which signals cell proliferation, differentiation, survival and death. The dysfunction of such signaling pathway causes syndromes with overlapping clinical manifestations. Skin and adnexal lesions are the cardinal clinical signs of RASopathies, such as cardiofaciocutaneous syndrome, Noonan syndrome with multiple lentigines, formerly known as LEOPARD syndrome, Costello syndrome, neurofibromatosis (NF1), Legius syndrome, Noonan-like syndrome with loose anagen hair (NSLH) and Noonan syndrome. As NF1, one of the most common RASopathies, described in 1882, has its clinical features well delineated, we will focus on the dermatological diagnosis, management and care of non-NF1 RASopathies, which are less known and more recently described. Dermatological manifestations are important clinical diagnostic elements that can aid differential diagnosis among RASopathies. They can affect dermis and epidermis, causing pigmented lesions (melanocytic nevi, café-au-lait spots, and lentigines), hyperkeratosis (keratosis pilaris, ulerythema ophryogenes, and palmoplantar keratosis) or hyperplasia. To date there are rare known links to malignancy, but oftentimes skin lesions require close attention because they can highly affect quality of life.

Prevalence of bladder cancer in Costello syndrome: New insights to drive clinical decision-making.

Costello syndrome (CS) is a rare disorder affecting development and growth characterized by cancer predisposition and caused by mutations in HRAS proto-oncogene. Somatic HRAS mutations drive bladder carcinogenesis. The aim of this study was to analyze prevalence and histological characterization of bladder cancer (BC) in a cohort of patients with CS to help clinicians plan effective management strategies. This study included 13 patients above 10 years of age with molecular diagnosis of CS. Screening cystoscopies (31 total procedures) were performed to exclude BC. Any lesion was analyzed through cold-cup biopsy or trans-urethral resection of the bladder. According to histology, patients were followed-up with urinalysis and abdominal ultrasound yearly, and cystoscopies every 12-24 months. During study enrollment, bladder lesions (often multifocal) were detected in 11/13 patients. Histological analysis documented premalignant lesions in 90% of cystoscopies performed, epithelial dysplasia in 71%, and papillary urothelial neoplasm of low-malignant potential in 19%. BC G1/low grade (Ta) were removed in 10%. Overall, 76% of patients showed a bladder lesion at first cystoscopy. The present findings document that individuals with CS aged 10 years and older have high prevalence of bladder lesions (premalignant/malignant), highlighting the importance of personalized screening protocols.

Clinical and molecular characterization of Costello syndrome in unrelated Mexican patients.

This study intends to describe for the first time a cohort of Mexican patients with Costello syndrome. The five exons of the HRAS gene were amplified in DNA samples from 13 patients with a clinical suspicion of Costello syndrome. PCR products were sequenced using the Ready Reaction Big Dye Terminator v.3.0 Kit and an ABI PRISM 310 sequencer. Only five patients (38%) showed causal variant in codon 12 of the HRAS gene (four with the p.Gly12Ser and one with the p.Gly12Ala variant). Three patients showed silent polymorphic variants (p.His27His and p.Leu159Leu). Clinical features in patients carrying the causal variant were variable. The alternative diagnosis of cardio-facio-cutaneous syndrome was considered in patients who did not have a causative variant in HRAS.

Craniosynostosis is a feature of Costello syndrome.

Costello syndrome (CS) is an autosomal dominant disorder caused by pathogenic variants in HRAS. Craniosynostosis is a known feature of other RASopathies (Noonan and cardiofaciocutaneous syndromes) but not CS. We describe four individuals with CS and craniosynostosis and present a summary of all previously reported individuals with craniosynostosis and RASopathy.

RASopathies: A significant cause of polyhydramnios?

OBJECTIVE: The aim of the study is to determine the prevalence of RASopathies in a polyhydramnios cohort selected by postnatal medical genetics evaluation. METHODS: In this retrospective study, we reviewed 622 pregnancies with polyhydramnios seen at Lucile Packard Children's Hospital between 2008 and 2017. The findings from 131 cases evaluated by Medical Genetics were included in our final analysis. Genetic testing information was extracted to determine the rate of chromosomal or single gene conditions focusing on the RASopathies. Additional variables collected were: maternal characteristics, ultrasound findings, and the severity and timing of diagnosis of polyhydramnios. RESULTS: Postnatal genetic testing or clinical examination identified a genetic disorder in 63 (48.1%) cases, more than half (n = 33) of which had a single gene condition. Postnatal testing revealed an underlying RASopathy in 15 (11.5%) cases. An underlying RASopathy was significantly associated with the severity and timing of polyhydramnios (p < 0.05). CONCLUSION: Focusing on a selected cohort postnatally evaluated by Medical Genetics, our study identified a chromosomal or genetic disorder in almost half of pregnancies complicated by polyhydramnios. Specifically, an underlying RASopathy was found in 11.5% of cases with 13/15 of these cases having additional ultrasound findings.

RASopathies.

RASopathies are a group of disorders characterized by mutations in the RAS-MAPK pathway. RAS-MAP signaling plays a critical role in cell differentiation, proliferation, and survival. Germline mutations can result in distinctive syndromes, including Noonan syndrome, Costello syndrome, and neurofibromatosis type 1. Mosaic RASopathies can present as localized cutaneous lesions like epidermal nevi and nevus sebaceous, or more extensive conditions such as encephalocraniocutaneous lipomatosis. We review the heterogenous presentation of RAS mutations, discuss new targeted therapies, and highlight areas of uncertainty, including carcinogenesis risk and appropriate screening.

Clinical and molecular characterization of children with Noonan syndrome and other RASopathies in Argentina. / Caracterización clínica y molecular de niños con síndrome de Noonan y otras RASopatías en Argentina.

INTRODUCTION: RASopathies are a set of syndromes with phenotypic overlapping features caused by gene mutations involved in the RAS/MAPK pathway. They are autosomal dominantly inherited and share common clinical characteristics, including short stature, craniofacial dysmorphisms, congenital heart disease, ectodermal manifestations, and a higher risk for cancer. A molecular diagnosis is a key factor. OBJECTIVE: To identify PTPN11, SOS1, RAF1, BRAF, and HRAS mutations and compare the main clinical characteristics of patients with molecular confirmation. Population and methods. Children with a clinical diagnosis of RASopathy assessed between August 2013 and February 2017. RESULTS: Mutations were identified in 71 % (87/122) of patients. The molecular test confirmed diagnosis in 73 % of patients with Noonan syndrome. The most prevalent mutation was c.922A>G (p.Asn308Asp) in the PTPN11 gene. A previously undescribed variant in RAF1 was detected: c.1467G>>C (p.Leu489Phe). Cardiofaciocutaneous syndrome was confirmed in 67 % of cases with BRAF mutations. Costello syndrome and Noonan syndrome with multiple lentigines were confirmed in all cases. CONCLUSION: The confirmation of clinical diagnosis allowed for a more accurate differential diagnosis. The prevalence of PTPN11 (58 %), SOS1 (10 %), and RAF1 mutations (5 %) in children with Noonan syndrome, of PTPN11 mutations (100 %) in those with Noonan syndrome with multiple lentigines, of BRAF mutations (67 %) in those with cardiofaciocutaneous syndrome, and of HRAS mutations (100 %) in those with Costello syndrome was determined.

Introducción. Las RASopatías son un conjunto de síndromes fenotípicamente superpuestos causados por mutaciones en genes implicados en la vía RAS/MAPK. La herencia es autosómica dominante, presentan características clínicas comunes, como baja talla, dismorfias craneofaciales, cardiopatía congénita, manifestaciones ectodérmicas y mayor riesgo de cáncer. El diagnóstico molecular es clave. Objetivo. Identificar mutaciones en los genes PTPN11, SOS1, RAF1, BRAF y HRAS, y comparar las principales características clínicas en pacientes con confirmación molecular. Población y métodos. Se estudiaron niños con diagnóstico clínico de RASopatía evaluados entre agosto de 2013 y febrero de 2017. Resultados. Se identificaron mutaciones en el 71 % (87/122) de los pacientes. El estudio molecular confirmó el diagnóstico en el 73 % de los pacientes con síndrome de Noonan. La mutación más prevalente fue c.922A>G (p.Asn308Asp) en el gen PTPN11. Se detectó una variante no descrita en RAF1, c.1467G>C (p.Leu489Phe). Se confirmó el síndrome cardiofaciocutáneo en el 67 % de los casos con mutaciones en el gen BRAF. El síndrome de Costello y el síndrome de Noonan con múltiples lentigos se confirmaron en todos los casos. Conclusión. La confirmación del diagnóstico clínico permitió un diagnóstico diferencial más preciso. Se determinó la prevalencia de las mutaciones en PTPN11 (el 58 %), SOS1 (el 10 %) y RAF1 (el 5 %) en niños con síndrome de Noonan, en PTPN11 (el 100 %) en el síndrome de Noonan con múltiples lentigos, en BRAF (el 67 %) en el síndrome cardiofaciocutáneo y en HRAS (el 100 %) en el síndrome de Costello.

Pain in individuals with RASopathies: Prevalence and clinical characterization in a sample of 80 affected patients.

Pain in individuals with RASopathies is a neglected topic in literature. In this article, we assessed prevalence and profile of pain in a sample of 80 individuals affected by RASopathies. The study sample included individuals with Noonan syndrome (N = 42), Costello syndrome (N = 17), and cardio-facio-cutaneous syndrome (N = 21). A set of standardized questionnaires and scales were administered (VAS/numeric scale, r-FLACC, Wang-Baker scale, NPSI, BPI, NCCPC-R) to detect and characterize acute and chronic pain and to study the influence of pain on quality of life (PEDs-QL, SF-36) and sleeping patterns (SDSC); revision of past medical history and multisystemic evaluation was provided. Available clinical data were correlated to the presence of pain. High prevalence of acute (44%) and chronic (61%) pain was documented in the examined sample. Due to age and intellectual disability, acute pain was localized in 18/35 individuals and chronic pain in 33/49. Muscle-skeletal and abdominal pain was more frequently reported. The intensity of acute and chronic pain interfered with daily activities in 1/3 of the sample. Pain negatively impacted on QoL and sleeping patterns. This work documents that pain is highly prevalent in RASopathies. Future studies including subjective and objective measures of pain are required to discriminate a somatosensory abnormality from an abnormal elaboration of painful stimuli at a central level.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients.

BACKGROUND: Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification. OBJECTIVES: To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations. METHODS: We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined. CONCLUSIONS: A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

FOXI2: a possible gene contributing to ectodermal dysplasia.

Cardio-facio-cutaneous syndrome (CFC), Noonan syndrome (NS), and Costello syndrome are a group of diseases that belong to the RASopathies. The syndromes share clinical features making diagnosis a challenge. To investigate the phenotype and genotype of a 10-year-old Iraqi girl with overlapping features of CFC, NS, and Costello syndromes, with additional features of ectodermal dysplasia. DNA was examined by exome sequencing and protein expression by immunohistochemistry. Exome sequencing identified a mutation in the SOS1 gene and a de novo deletion in the FOXI2 gene which was neither present in the international databases, nor in 400 chromosomes from the same population. Based on immunohistochemical staining, FOXI2 was identified in the basal cell layer of the skin and overlapped with the expression of P63, a major player in ectodermal dysplasia. We therefore suggest screening for FOXI2 mutation in the setting of ectodermal features that are not associated with genes known to contribute to ectodermal dysplasia.

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.

Attenuated phenotype of Costello syndrome and early death in a patient with an HRAS mutation (c.179G>T; p.Gly60Val) affecting signalling dynamics.

Costello syndrome (CS) is caused by heterozygous germline HRAS mutations. Most patients share the HRAS mutation c.34G>A (p.Gly12Ser) associated with the typical, relatively homogeneous phenotype. Rarer mutations occurred in individuals with an attenuated phenotype. Although many disease-associated HRAS alterations trigger constitutive activation of HRAS-dependent signalling pathways, additional pathological consequences exist. An infant with failure-to-thrive and hypertrophic cardiomyopathy had a novel de novo HRAS mutation (c.179G>T; p.Gly60Val). He showed subtle dysmorphic findings consistent with attenuated CS and died from presumed cardiac cause. Functional studies revealed that amino acid change p.Gly60Val impairs HRAS binding to effectors PIK3CA, phospholipase C1, and RAL guanine nucleotide dissociation stimulator. In contrast, interaction with effector rapidly accelerated fibrosarcoma (RAF) and regulator NF1 GTPase-activating protein was enhanced. Importantly, expression of HRAS p.Gly60Val in HEK293 cells reduced growth factor sensitivity leading to damped RAF-MAPK and phosphoinositide 3-kinases-AKT signalling response. Our data support the idea that a variable range of dysregulated HRAS-dependent signalling dynamics, rather than static activation of HRAS-dependent signal flow, may underlie the phenotypic variability in CS.

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.

Objective studies of the face of Noonan, Cardio-facio-cutaneous, and Costello syndromes: A comparison of three disorders of the Ras/MAPK signaling pathway.

Noonan, Cardio-facio-cutaneous, and Costello syndromes are disorders of the Ras/MAPK pathway that share many clinical features. This observational and anthropometric study was conducted to describe the key facial features of each syndrome in order to improve discrimination between the three conditions, particularly in young children where diagnosis is most challenging. Direct measurement of the head and face was used to enhance diagnostic accuracy, and identify the most unusual or specific dimensions. The Noonan syndrome cohort included 123 individuals, aged 6 months to 41 years. There were 20 children and adolescents with Cardio-facio-cutaneous syndrome, and 28 individuals with Costello syndrome, aged 1-32 years. The facial phenotypes of these syndromes, particularly Noonan syndrome, are well-described but objective data have not been published in peer-reviewed literature. In this study, subjective observations, in the main, were validated by anthropometry with one exception. In individuals with Costello syndrome, mouth width was normal, thus the impression of wide mouth is likely due to full lips or the mouth being viewed in relation to a narrow lower face. When the three conditions were compared objectively, syndrome-specific pattern profiles showed high concordance in early life. At older ages, Cardio-facio-cutaneous syndrome was distinguished by increased width of the mid/lower face, and reduced growth of maxillary and mandibular dimensions was noted in both Noonan and Costello syndromes. Despite substantial similarities in face shape in older individuals with these two conditions, bulbous nasal tip, full lips, and an apparently wide mouth in those with Costello Syndrome facilitate discrimination from Noonan syndrome. © 2016 Wiley Periodicals, Inc.

Respiratory system involvement in Costello syndrome.

Costello syndrome (CS) is a multisystem disorder caused by heterozygous germline mutations in the HRAS proto-oncogene. Respiratory system complications have been reported in individuals with CS, but a comprehensive description of the full spectrum and incidence of respiratory symptoms in these patients is not available. Here, we report the clinical course of four CS patients with respiratory complications as a major cause of morbidity. Review of the literature identified 56 CS patients with descriptions of their neonatal course and 17 patients in childhood/adulthood. We found that in the neonatal period, respiratory complications are seen in approximately 78% of patients with transient respiratory distress reported in 45% of neonates. Other more specific respiratory diagnoses were reported in 62% of patients, the majority of which comprised disorders of the upper and lower respiratory tract. Symptoms of upper airway obstruction were reported in CS neonates but were more commonly diagnosed in childhood/adulthood (71%). Analysis of HRAS mutations and their respiratory phenotype revealed that the common p.Gly12Ser mutation is more often associated with transient respiratory distress and other respiratory diagnoses. Respiratory failure and dependence on mechanical ventilation occurs almost exclusively with rare mutations. In cases of prenatally diagnosed CS, the high incidence of respiratory complications in the neonatal period should prompt anticipatory guidance and development of a postnatal management plan. This may be important in cases involving rarer mutations. Furthermore, the high frequency of airway obstruction in CS patients suggests that otorhinolaryngological evaluation and sleep studies should be considered. © 2016 Wiley Periodicals, Inc.

The rare Costello variant HRAS c.173C>T (p.T58I) with severe neonatal hypertrophic cardiomyopathy.

We report a 10-year-old girl presenting with severe neonatal hypertrophic cardiomyopathy (HCM), feeding difficulties, mildly abnormal facial features, and progressive skeletal muscle symptoms but with normal cognitive development. Targeted oligonucleotide-selective sequencing of 101 cardiomyopathy genes revealed the genetic diagnosis, and the mutation was verified by Sanger sequencing in the patient and her parents. To offer insights into the potential mechanism of patient mutation, protein structural analysis was performed using the resolved structure of human activated HRAS protein with bound GTP analogue (PDB id 5P21) in Discovery Studio 4.5 (Dassault Systèmes Biovia, San Diego, CA). The patient with hypertrophic cardiomyopathy and normal cognitive development was diagnosed with an HRAS mutation c.173C>T (p.T58I), a milder variant of Costello syndrome affecting a highly conserved amino acid, threonine 58. Our analysis suggests that the p.G12 mutations slow GTP hydrolysis rendering HRAS unresponsive to GTPase activating proteins, and resulting in permanently active state. The p.T58I mutation likely affects binding of guanidine-nucleotide-exchange factors, thereby promoting the active state but also allowing for slow inactivation. Patients with the HRAS mutation c.173C>T (p.T58I) might go undiagnosed because of the milder phenotype compared with other mutations causing Costello syndrome. We expand the clinical and molecular picture of the rare HRAS mutation by reporting the first case in Europe and the fourth case in the literature. Our protein structure analysis offers insights into the mechanism of the mildly activating p.T58I mutation. © 2016 Wiley Periodicals, Inc.

Recombinant growth hormone therapy in a girl with Costello syndrome: a 4-year observation.

BACKGROUND: Costello syndrome is a rare syndrome of multiple congenital anomalies. The typical clinical traits include dysmorphic craniofacial features, skin hyperpigmentation and excess, feeding difficulties leading to severe postnatal growth retardation, short stature, joint hypermobility, and delayed psychomotor development. Additionally, Costello syndrome may present with an increased incidence of congenital heart disease, hypertrophic cardiomyopathy, and increased risk of both benign and malignant tumors. Furthermore, cases of patients with endocrine disorders such as adrenal insufficiency and endogenous growth hormone deficiency have also been documented. CASE PRESENTATION: We present a patient with Costello syndrome who has been successfully treated with recombinant human growth hormone (rhGH) for almost 4 years. CONCLUSIONS: The possibility of growth hormone (GH) treatment can be considered in cases of documented GH deficiency in patients with Costello syndrome, but only under close oncologic and cardiologic supervision.