Expanding the clinical phenotype of RASopathies in 38 Turkish patients, including the rare LZTR1, RAF1, RIT1 variants, and large deletion in NF1.

RASopathies are a group of disorders caused by pathogenic variants in the genes encoding Ras/mitogen-activated protein kinase pathway and share overlapping clinical and molecular features. This study is aimed to describe the clinical and molecular features of 38 patients with RASopathies. Sanger or targeted next-generation sequencing of related genes and multiplex ligation-dependent-probe amplification analysis for NF1 were performed. The pathogenic variant detection rate was 94.4%. While PTPN11 was responsible for 50% of 18 patients with Noonan syndrome (NS), SOS1, LZTR1, RIT1, and RAF1 were responsible for the remaining 27.8%, 11.1%, 5.5%, and 5.5%, respectively. Three variants in LZTR1 were novel, of which two were identified in the compound heterozygous state in a patient with intellectual disability and hypertrophic cardiomyopathy, whereas the third variant was found in the heterozygous state in a patient with pulmonary stenosis and normal intelligence. We described pyloric stenosis, knee dislocation, and cleft palate in patients with SOS1, RIT1, and RAF1 variants, respectively, that was not previously reported. We detected a PTPN11 variant in three patients from same family with NS with multiple lentigines. BRAF and MAP2K2 variants were found in eight patients with Cardiofaciocutaneous syndrome. Two variants in HRAS were detected in two Costello syndrome patients, one with a mild and the other with a severe phenotype. While large NF1 deletions were identified in four Neurofibromatosis-NS patients with intellectual disability, intelligence was normal in one patient with missense variant. In conclusion, this study provided three novel variants in LZTR1 and expanded the clinical phenotype of rare RASopathies.

Cardiac manifestations and gene mutations of patients with RASopathies in Taiwan.

RASopathies are developmental diseases caused by mutations in rat sarcoma-mitogen-activated protein kinase pathway genes. These disorders, such as Noonan syndrome (NS) and NS-related disorders (NSRD), including cardio-facio-cutaneous (CFC) syndrome, Costello syndrome (CS), and NS with multiple lentigines (NSML; also known as LEOPARD syndrome), have a similar systemic phenotype. A wide spectrum of congenital heart disease and hypertrophic cardiomyopathy (HCMP) can exhibit major associated characteristics. A retrospective study was conducted at the Mackay Memorial Hospital, National Taiwan University Hospital, Buddhist Tzu-Chi General Hospital, Chang-Gung Memorial Hospital, Taichung Veterans General Hospital, and Chung Shan Medical University Hospital from January 2007 to December 2018. We reviewed the clinical records of 76 patients with a confirmed molecular diagnosis of RASopathies, including NS, CS, CFC syndrome, and NSML. We evaluated the demographic data and medical records with clinical phenotypes of cardiac structural anomalies using cross-sectional and color Doppler echocardiography, electrocardiographic findings, and follow-up data. A total of 47 (61.8%) patients had cardiac abnormalities. The prevalence of cardiac lesions according to each syndrome was 62.7, 50.0, 60.0, and 66.7% in patients with NS, CFC syndrome, CS, and NSML, respectively. An atrial septal defect was usually combined with other cardiac abnormalities, such as pulmonary stenosis (PS), HCMP, ventricular septal defect, or patent ductus arteriosus. Patients with NS most commonly showed PS. In patients with NSRD and cardiac abnormalities, HCMP (29.4%) was the most commonly observed cardiac lesion. PTPN11 was also the most frequently detected mutation in patients with NS and NSRD. Cardiac abnormalities were the most common symptoms observed in patients with RASopathies at the time of their first hospital visit. Performing precise analyses of genotype-cardiac phenotype correlations in a larger cohort will help us accurately diagnose RASopathy as soon as possible.

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.

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.

RASopathies are associated with a distinct personality profile.

Personality is a complex, yet partially heritable, trait. Although some Mendelian diseases like Williams-Beuren syndrome are associated with a particular personality profile, studies have failed to assign the personality features to a single gene or pathway. As a family of monogenic disorders caused by mutations in the Ras/MAPK pathway known to influence social behavior, RASopathies are likely to provide insight into the genetic basis of personality. Eighty subjects diagnosed with cardiofaciocutaneous syndrome, Costello syndrome, neurofibromatosis type 1, and Noonan syndrome were assessed using a parent-report BFQ-C (Big Five Questionnaire for Children) evaluating agreeableness, extraversion, conscientiousness, intellect/openness, and neuroticism, along with 55 unaffected sibling controls. A short questionnaire was added to assess sense of humor. RASopathy subjects and sibling controls were compared for individual components of personality, multidimensional personality profiles, and individual questions using Student tests, analysis of variance, and principal component analysis. RASopathy subjects were given lower scores on average compared to sibling controls in agreeableness, extraversion, conscientiousness, openness, and sense of humor, and similar scores in neuroticism. When comparing the multidimensional personality profile between groups, RASopathies showed a distinct profile from unaffected siblings, but no difference in this global profile was found within RASopathies, revealing a common profile for the Ras/MAPK-related disorders. In addition, several syndrome-specific strengths or weaknesses were observed in individual domains. We describe for the first time an association between a single pathway and a specific personality profile, providing a better understanding of the genetics underlying personality, and new tools for tailoring educational and behavioral approaches for individuals with RASopathies.

Phenotypic spectrum of Costello syndrome individuals harboring the rare HRAS mutation p.Gly13Asp.

Costello syndrome is part of the RASopathies, a group of neurocardiofaciocutaneous syndromes caused by deregulation of the RAS mitogen-activated protein kinase pathway. Heterozygous mutations in HRAS are responsible for Costello syndrome, with more than 80% of the patients harboring the specific p.Gly12Ser variant. These individuals show a homogeneous phenotype. The clinical characteristics of the Costello syndrome individuals harboring rarer HRAS mutations are less understood, due to the small number of reported cases. Here, we describe the phenotypic spectrum of five additional individuals with HRAS c.38G>A; p.Gly13Asp, including one with somatic mosaicism, and review five previously described cases. The facial and hair abnormalities of the HRAS p.Gly13Asp individuals differ from the typical pattern observed in those showing the common HRAS (p.Gly12Ser) mutation, with less coarse facial features and slow growing, sparse hair with abnormal texture, the latter resembling the pattern observed in Noonan syndrome-like disorder with loose anagen hair and individuals harboring another amino acid substitution in HRAS (p.Gly13Cys). Although some individuals with HRAS p.Gly13Asp developed papillomata and vascular proliferation lesions, no malignant tumors occurred, similar to what was reported for individuals harboring the HRAS p.Gly13Cys. The fact that no malignant tumors were described in these individuals does not allow definitive conclusions about the risk for cancer development. It remains to be determined if substitutions of amino acid 13 in HRAS (p.Gly13Asp and p.Gly13Cys) increase the risk of tumor development.

Mechanisms underlying cognitive deficits in a mouse model for Costello Syndrome are distinct from other RASopathy mouse models.

RASopathies, characterized by germline mutations in genes encoding proteins of the RAS-ERK signaling pathway, show overlapping phenotypes, which manifest themselves with a varying severity of intellectual disability. However, it is unclear to what extent they share the same downstream pathophysiology that underlies the cognitive deficits. Costello syndrome (CS) is a rare RASopathy caused by activating mutations in the HRAS gene. Here we investigated the mechanisms underlying the cognitive deficits of HRas G12V/G12V mice. HRas G12V/G12V mice showed robust upregulation of ERK signaling, neuronal hypertrophy, increased brain volume, spatial learning deficits, and impaired mGluR-dependent long-term depression (LTD). In contrast, long-term potentiation (LTP), which is affected in other RASopathy mouse models was unaffected. Treatment with lovastatin, a HMG-CoA-Reductase inhibitor which has been shown to rescue the behavioral phenotypes of mouse models of NF1 and Noonan syndrome, was unable to restore ERK signaling and the cognitive deficits of HRas G12V/G12V mice. Administration of a potent mitogen-activated protein kinase (MEK) inhibitor rescued the ERK upregulation and the mGluR-LTD deficit of HRas G12V/G12V mice, but failed to rescue the cognitive deficits. Taken together, this study indicates that the fundamental molecular and cellular mechanisms underlying the cognitive aspects of different RASopathies are remarkably distinct, and may require disease specific treatments.

Age-related differences in prevalence of autism spectrum disorder symptoms in children and adolescents with Costello syndrome.

Dysregulation of the mitogen activated protein kinase (MAPK) pathway in Costello syndrome (CS) may contribute to increased risk for autism-spectrum disorder (ASD). We examined prevalence of ASD symptoms in 14 individuals (six females) age 1-18 years with molecularly confirmed CS. Caregivers completed the Modified Checklist for Autism in Toddlers (M-CHAT) for ages 0-4 years (n = 7), and the Social Communication Questionnaire (SCQ) for ages 4 and older (n = 7). Age was associated with meeting ASD criteria: 5/7 (71.4%) younger children met the ASD cut-off on the MCHAT, compared to 0/7 older children on the SCQ. The following medical and developmental factors were strongly associated with ASD criteria on the M-CHAT: having a gastrostomy tube at time of assessment, not eating solid food, not walking, and not being toilet trained. Two children who met stricter ASD criteria had significantly lower adaptive functioning and were physically much more impaired. Among older participants, SCQ subscale scores in communication, socialization, and repetitive behavior domains were comparable to the typically-developing normative sample. ASD symptoms were highly elevated in younger CS individuals. Older children did not differ from typically developing samples in prevalence of ASD symptoms. CS individuals may appear to fall on the autism spectrum in early childhood due to severe feeding and orthopedic problems that improve by age four, suggesting many of these children may eventually emerge out of an ASD presentation.

Retinal dystrophy in two boys with Costello syndrome due to the HRAS p.Gly13Cys mutation.

Features of Costello Syndrome, a systemic disorder caused by germline mutations in the proto-oncogene HRAS from the RAS/MAPK pathway, include failure-to-thrive, short stature, coarse facial features, cardiac defects including hypertrophic cardiomyopathy, intellectual disability, and predisposition to neoplasia. Two unrelated boys with Costello syndrome and an HRAS mutation (p.Gly13Cys) are presented with their ophthalmologic findings. Both had early symptoms of nystagmus, photophobia, and vision abnormalities. Fundus examination findings of retinal dystrophy were present at age 3 years. Both boys have abnormal electroretinograms with reduced or undetectable rod responses along with reduced cone responses consistent with rod-cone dystrophy. Our observations suggest that early ophthalmic examination and re-evaluations are indicated in children with Costello syndrome.

Before and after - Nutritional transformation of dysmorphism in a case of Costello syndrome.

Costello syndrome is a type of RASopathy mapped to HRAS gene in chromosome 11, characterized by prenatal overgrowth, postnatal failure to thrive, classic facial gestalt and multisystem involvement including cardiomyopathy and intellectual disability. We present a 7 months old child with severe failure to thrive whose "subtle" facial dysmorphism at the time eluded clinical recognition of the syndrome. It was only with optimization of his nutritional status that dysmorphic features became more apparent, which affirmed the molecular diagnosis of Costello syndrome from exome sequencing. The case illustrated how drastic failure to thrive can be in Costello syndrome, and how nutritional status can transform dysmorphic features in a child. It also highlights the importance of serial dysmorphic evaluation in difficult cases.

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.

Differential Effects of HRAS Mutation on LTP-Like Activity Induced by Different Protocols of Repetitive Transcranial Magnetic Stimulation.

BACKGROUND: Costello syndrome (CS) is a rare congenital disorder due to a G12S amino acid substitution in HRAS protoncogene. Previous studies have shown that Paired Associative Stimulation (PAS), a repetitive brain stimulation protocol inducing motor cortex plasticity by coupling peripheral nerve stimulation with brain stimulation, leads to an extremely pronounced motor cortex excitability increase in CS patients. Intermittent Theta Burst Stimulation (iTBS) represents a protocol able to induce motor cortex plasticity by trains of stimuli at 50 Hz. In healthy subjects PAS and iTBS produce similar after-effects in motor cortex excitability. Experimental models showed that HRAS-dependent signalling pathways differently affect LTP induced by different patterns of repetitive synaptic stimulation. OBJECTIVE: We aimed to compare iTBS-induced after-effects on motor cortex excitability with those produced by PAS in CS patients and to observe whether HRAS mutation differentially affects two different forms of neuromodulation protocols. METHODS: We evaluated in vivo after-effects induced by PAS and iTBS applied over the right motor cortex in 4 CS patients and in 21 healthy age-matched controls. RESULTS: Our findings confirmed HRAS-dependent extremely pronounced PAS-induced after-effects and showed for the first time that iTBS induces no change in MEP amplitude in CS patients whereas both protocols lead to an increase of about 50% in controls. CONCLUSIONS: CS patients are characterized by an impairment of iTBS-related LTP-like phenomena besides enhanced PAS-induced after-effects, suggesting that HRAS-dependent signalling pathways have a differential influence on PAS- and iTBS-induced plasticity in humans.

Function and disability in children with Costello syndrome and Cardiofaciocutaneous syndrome.

There is limited research on function in individuals with RASopathies. Our hypothesis was that there was function and disability differences between Costello syndrome (CS) and Cardiofaciocutaneous syndrome (CFCS). The purpose of this study was to describe and compare the functional performance and level of disability of children with CS and CFCS using the Pediatric Outcomes Data Collection Instrument (PODCI) and Pediatric Evaluation of Disability Index (PEDI). Parents of individuals with a medical diagnosis of CS and CFCS completed the computer or paper version of the questionnaires. Comparisons of response data were made between the two syndromes and published normative data. Fifty-two parents participated in the study, 38 in the CS group and 14 in the CFCS group. There were no significant differences in PODCI or PEDI scores between the CS and CFCS groups. There were statistically significant differences from normative values for all PODCI domains (P ≤ 0.012). The PEDI T-scores of both groups were greater than two standard deviations below normative scores in mobility (CS = 12.37, CFCS = 2.37), social (CS = 24.01, CFCS = 20.08), and activity (CS = 15.88, CFCS = 14.32). Responsibility T scores were in the normal range (30-70) for the CS group (31.38), but not for the CFCS group (28.40). The CS and CFCS groups had activity limitations in the PODCI domains of upper extremity function, transfers, and mobility, sport and physical function. These functional limitations cause significant disability in the PEDI domains of daily activity, mobility, and socialization and cognition. CS and CFCS are similar conditions in respect to functional limitations and severity of disability.

Syndrome in question

Costello syndrome (CS) is a rare genetic disorder, first described by Costello in 1971, caused by mutations in the HRAS proto-oncogene. Clinical findings include facial dysmorphism, skin disorders, cognitive impairment, cardiac and musculoskeletal defects. There is an increased risk of malignancies in these patients, due to the proto-oncogene mutation, and also sudden death secondary to heart disease. We report a case with characteristic phenotype, highlighting the peculiar skin changes.

Syndrome in question. Costello syndrome.

Costello syndrome (CS) is a rare genetic disorder, first described by Costello in 1971, caused by mutations in the HRAS proto-oncogene. Clinical findings include facial dysmorphism, skin disorders, cognitive impairment, cardiac and musculoskeletal defects. There is an increased risk of malignancies in these patients, due to the proto-oncogene mutation, and also sudden death secondary to heart disease. We report a case with characteristic phenotype, highlighting the peculiar skin changes.

Decreased bone mineral density in Costello syndrome.

INTRODUCTION: Costello syndrome (CS) is a multisystemic disorder characterized by postnatal reduced growth, facial dysmorphism, cardiac defects, cognitive impairment, skin and musculo-skeletal anomalies, and predisposition to certain cancers. CS is caused by activating germline mutations in the HRAS proto-oncogene. Similar to what is observed in other RASopathies, CS causative HRAS mutations promote enhanced signal flow through the RAF-MEK-ERK and PI3K-AKT signaling cascades. While decreased bone mineralization has been documented in other RASopathies, such as neurofibromatosis type 1 and Noonan syndrome, systematic studies investigating bone mineral density (BMD) are lacking in CS. MATERIALS AND METHODS: Dual-energy X-ray absorptiometry (DXA) was utilized to assess BMD and body composition (fat and fat-free mass) in a cohort of subjects with molecularly confirmed diagnosis of CS (n = 9) and age-matched control individuals (n = 29). Using general linear regression, subtotal body (total body less head), lumbar, femoral neck and femur BMD parameters were compared considering age, sex, body mass index (BMI) and Tanner stage. Blood and urine biomarkers of bone metabolism were also assessed. RESULTS: All individuals with CS showed significantly lower mean values of subtotal, lumbar and femoral neck BMD compared to the control group (p ≤ 0.01). Similarly, mean total body mass and fat-free mass parameters were lower among the CS patients than in controls (p < 0.01). Low 25-OH vitamin D concentration was documented in all individuals with CS, with values below the reference range in two patients. No significant correlation between vitamin D levels and BMD parameters was observed. DISCUSSION: CS belongs to a family of developmental disorders, the RASopathies, that share skeletal defects as a common feature. The present data provide evidence that, similar to what is recently seen in NF1 and NS, bone homeostasis is impaired in CS. The significant decrease in BMD and low levels of vitamin D documented in the present cohort, along with the risk for pathologic fractures reported in adult individuals with CS, testifies the requirement for a preventive treatment to alleviate evolutive complications resulting from dysregulated bone metabolism.

Antioxidant effects of potassium ascorbate with ribose in costello syndrome.

BACKGROUND: Costello syndrome is a rare genetic condition characterized by coarse facies, short stature, loose folds of skin especially on hands and feet, severe feeding difficulties and failure to thrive. Other features include cardiac anomalies, developmental disability and increased risk of neoplasms. Given the link between oxidative stress (OS) and carcinogenesis, we tested the hypothesis that OS occurs in this syndrome, supposing its role both in cancer development and in other clinical features. PATIENTS AND METHODS: We describe four cases with Costello syndrome in which we verified the presence of OS by measuring a redox biomarker profile including total hydroperoxides, non-protein-bound iron, advanced oxidation protein products, thyols, carbonyl groups and isoprostanes. Thus, we introduced an antioxidant agent, namely potassium ascorbate with ribose (PAR) into the therapy and monitored the redox profile every three months to verify its efficacy. RESULTS: A progressive decrease in OS biomarkers occurred, together with an improvement in the clinical features of the patients. CONCLUSION: OS was proven in all four cases of Costello syndrome. The antioxidant therapy with PAR demonstrated positive effects. These promising results need further research to confirm the relevance of OS and the efficacy of PAR therapy in Costello syndrome.

Peripheral muscle weakness in RASopathies.

INTRODUCTION: RASopathies are a group of genetic conditions due to alterations of the Ras/MAPK pathway. Neurocutaneous findings are hallmark features of the RASopathies, but musculoskeletal abnormalities are also frequent. The objective was to evaluate handgrip strength in the RASopathies. METHODS: Individuals with RASopathies (e.g., Noonan syndrome, Costello syndrome, cardio-facio-cutaneous [CFC] syndrome, and neurofibromatosis type 1 [NF1]) and healthy controls were evaluated. Two methods of handgrip strength were tested: GRIP-D Takei Hand Grip Dynamometer and the Martin vigorimeter. A general linear model was fitted to compare average strength among the groups, controlling for confounders such as age, gender, height, and weight. RESULTS: Takei dynamometer: handgrip strength was decreased in each of the syndromes compared with controls. Decreased handgrip strength compared with sibling controls was also seen with the Martin vigorimeter (P < 0.0001). CONCLUSIONS: Handgrip strength is decreased in the RASopathies. The etiology of the reduced muscle force is unknown, but likely multifactorial.

Dystonia in Costello syndrome.

BACKGROUND: Costello Syndrome is a rare multiple congenital anomaly disorder caused by de novo heterozygous mutations in the v-Ha-ras Harvey rat sarcoma viral oncogene homolog (HRAS) gene. Recent studies seem to support apparent autosomal dominant inheritance and somatic mosaicism and an association with advanced parental age. Abnormal hand posture has been reported as a typical feature of Costello Syndrome but the pathophysiology of this is unclear. METHODS: We evaluated and described posture and movement in six consecutive subjects with genetically proven Costello Syndrome, in order to better characterize the phenomenology of the associated postural abnormalities and any related motor abnormalities. We also evaluated motor cortex plasticity by applying Paired Associative Stimulation. RESULTS: All the patients presented the typical postural abnormalities reported in Costello Syndrome, in particular the ulnar deviation of fingers. The latter was reducible and not fixed. In addition, patients exhibited more explicit dystonic features of the face, limbs and trunk and altered sensorimotor plasticity consistent with generalized dystonia. CONCLUSIONS: These findings suggest that dystonia may underlie the abnormal postures described in Costello Syndrome patients.