Hyperactive HRAS dysregulates energetic metabolism in fibroblasts from patients with Costello syndrome via enhanced production of reactive oxidizing species.

Germline-activating mutations in HRAS cause Costello syndrome (CS), a cancer prone multisystem disorder characterized by reduced postnatal growth. In CS, poor weight gain and growth are not caused by low caloric intake. Here, we show that constitutive plasma membrane translocation and activation of the GLUT4 glucose transporter, via reactive oxygen species-dependent AMP-activated protein kinase α and p38 hyperactivation, occurs in primary fibroblasts of CS patients, resulting in accelerated glycolysis and increased fatty acid synthesis and storage as lipid droplets. An accelerated autophagic flux was also identified as contributing to the increased energetic expenditure in CS. Concomitant inhibition of p38 and PI3K signaling by wortmannin was able to rescue both the dysregulated glucose intake and accelerated autophagic flux. Our findings provide a mechanistic link between upregulated HRAS function, defective growth and increased resting energetic expenditure in CS, and document that targeting p38 and PI3K signaling is able to revert this metabolic dysfunction.

Expanding the molecular spectrum of pathogenic SHOC2 variants underlying Mazzanti syndrome.

We previously molecularly and clinically characterized Mazzanti syndrome, a RASopathy related to Noonan syndrome that is mostly caused by a single recurrent missense variant (c.4A > G, p.Ser2Gly) in SHOC2, which encodes a leucine-rich repeat-containing protein facilitating signal flow through the RAS-mitogen-associated protein kinase (MAPK) pathway. We also documented that the pathogenic p.Ser2Gly substitution causes upregulation of MAPK signaling and constitutive targeting of SHOC2 to the plasma membrane due to the introduction of an N-myristoylation recognition motif. The almost invariant occurrence of the pathogenic c.4A > G missense change in SHOC2 is mirrored by a relatively homogeneous clinical phenotype of Mazzanti syndrome. Here, we provide new data on the clinical spectrum and molecular diversity of this disorder and functionally characterize new pathogenic variants. The clinical phenotype of six unrelated individuals carrying novel disease-causing SHOC2 variants is delineated, and public and newly collected clinical data are utilized to profile the disorder. In silico, in vitro and in vivo characterization of the newly identified variants provides evidence that the consequences of these missense changes on SHOC2 functional behavior differ from what had been observed for the canonical p.Ser2Gly change but converge toward an enhanced activation of the RAS-MAPK pathway. Our findings expand the molecular spectrum of pathogenic SHOC2 variants, provide a more accurate picture of the phenotypic expression associated with variants in this gene and definitively establish a gain-of-function behavior as the mechanism of disease.

Early neurological signs in infants identified through neonatal screening for SMA: do they predict outcome?

Neonatal screening for SMA has allowed the identification of infants who may present with early clinical signs. Our aim was to establish whether the presence and the severity of early clinical signs have an effect on the development of motor milestones. Infants identified through newborn screening were prospectively assessed using a structured neonatal neurological examination and an additional module developed for the assessment of floppy infants. As part of the follow-up, all infants were assessed using the HINE-2 to establish developmental milestones. Only infants with at least 24 months of follow-up were included. Normal early neurological examination (n = 11) was associated with independent walking before the age of 18 months while infants with early clinical signs of SMA (n = 4) did not achieve ambulation (duration follow-up 33.2 months). Paucisymptomatic patients (n = 3) achieved ambulation, one before the age of 18 months and the other 2 between 22 and 24 months.  Conclusion: Our findings suggest that early clinical signs may contribute to predict motor milestones development. What is Known: • There is increasing evidence of heterogeneity among the SMA newborns identified via NBS. • The proposed nosology describes a clinically silent disease, an intermediate category ('paucisymptomatic') and 'symptomatic SMA'. What is New: • The presence of minimal clinical signs at birth does not prevent the possibility to achieve independent walking but this may occur with some delay. • The combination of genotype at SMN locus and clinical evaluation may better predict the possibility to achieve milestones.

Genotypes and phenotypes heterogeneity in PIK3CA-related overgrowth spectrum and overlapping conditions: 150 novel patients and systematic review of 1007 patients with PIK3CA pathogenetic variants.

BACKGROUND: Postzygotic activating PIK3CA variants cause several phenotypes within the PIK3CA-related overgrowth spectrum (PROS). Variant strength, mosaicism level, specific tissue involvement and overlapping disorders are responsible for disease heterogeneity. We explored these factors in 150 novel patients and in an expanded cohort of 1007 PIK3CA-mutated patients, analysing our new data with previous literature to give a comprehensive picture. METHODS: We performed ultradeep targeted next-generation sequencing (NGS) on DNA from skin biopsy, buccal swab or blood using a panel including phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway genes and GNAQ, GNA11, RASA1 and TEK. Additionally, 914 patients previously reported were systematically reviewed. RESULTS: 93 of our 150 patients had PIK3CA pathogenetic variants. The merged PROS cohort showed that PIK3CA variants span thorough all gene domains, some were exclusively associated with specific PROS phenotypes: weakly activating variants were associated with central nervous system (CNS) involvement, and strongly activating variants with extra-CNS phenotypes. Among the 57 with a wild-type PIK3CA allele, 11 patients with overgrowth and vascular malformations overlapping PROS had variants in GNAQ, GNA11, RASA1 or TEK. CONCLUSION: We confirm that (1) molecular diagnostic yield increases when multiple tissues are tested and by enriching NGS panels with genes of overlapping 'vascular' phenotypes; (2) strongly activating PIK3CA variants are found in affected tissue, rarely in blood: conversely, weakly activating mutations more common in blood; (3) weakly activating variants correlate with CNS involvement, strong variants are more common in cases without; (4) patients with vascular malformations overlapping those of PROS can harbour variants in genes other than PIK3CA.

De Novo VPS4A Mutations Cause Multisystem Disease with Abnormal Neurodevelopment.

The endosomal sorting complexes required for transport (ESCRTs) are essential for multiple membrane modeling and membrane-independent cellular processes. Here we describe six unrelated individuals with de novo missense variants affecting the ATPase domain of VPS4A, a critical enzyme regulating ESCRT function. Probands had structural brain abnormalities, severe neurodevelopmental delay, cataracts, growth impairment, and anemia. In cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A. Proband-derived fibroblasts had enlarged endosomal structures with abnormal accumulation of the ESCRT protein IST1 on the limiting membrane. VPS4A function was also required for normal endosomal morphology and IST1 localization in iPSC-derived human neurons. Mutations affected other ESCRT-dependent cellular processes, including regulation of centrosome number, primary cilium morphology, nuclear membrane morphology, chromosome segregation, mitotic spindle formation, and cell cycle progression. We thus characterize a distinct multisystem disorder caused by mutations affecting VPS4A and demonstrate that its normal function is required for multiple human developmental and cellular processes.

Delineation of a KDM2B-related neurodevelopmental disorder and its associated DNA methylation signature.

PURPOSE: Pathogenic variants in genes involved in the epigenetic machinery are an emerging cause of neurodevelopment disorders (NDDs). Lysine-demethylase 2B (KDM2B) encodes an epigenetic regulator and mouse models suggest an important role during development. We set out to determine whether KDM2B variants are associated with NDD. METHODS: Through international collaborations, we collected data on individuals with heterozygous KDM2B variants. We applied methylation arrays on peripheral blood DNA samples to determine a KDM2B associated epigenetic signature. RESULTS: We recruited a total of 27 individuals with heterozygous variants in KDM2B. We present evidence, including a shared epigenetic signature, to support a pathogenic classification of 15 KDM2B variants and identify the CxxC domain as a mutational hotspot. Both loss-of-function and CxxC-domain missense variants present with a specific subepisignature. Moreover, the KDM2B episignature was identified in the context of a dual molecular diagnosis in multiple individuals. Our efforts resulted in a cohort of 21 individuals with heterozygous (likely) pathogenic variants. Individuals in this cohort present with developmental delay and/or intellectual disability; autism; attention deficit disorder/attention deficit hyperactivity disorder; congenital organ anomalies mainly of the heart, eyes, and urogenital system; and subtle facial dysmorphism. CONCLUSION: Pathogenic heterozygous variants in KDM2B are associated with NDD and a specific epigenetic signature detectable in peripheral blood.

Further case of enlarged spinal nerve roots in KRAS-related Noonan syndrome.

Noonan syndrome (NS) belongs to RASopathies, a family of disorders caused by unregulated signaling through the RAS-MAPK pathway. Herein, we report on an individual with molecularly confirmed diagnosis of NS showing asymptomatic enlarged spinal nerve roots, which are distinctive features of neurofibromatosis type 1. To date, a total of 16 patients with neurogenic tumors resembling neurofibromas/schwannomas and a molecularly confirmed diagnosis of a non-NF1 RASopathy have been reported, adding this further feature shared among RASopathies.

Congenital heart defects in CTNNB1 syndrome: Raising clinical awareness.

CTNNB1 [OMIM *116806] encodes ß-catenin, an integral part of the cadherin/catenin complex, which functions as effector of Wnt signaling. CTNNB1 is highly expressed in brain as well as in other tissues, including heart. Heterozygous CTNNB1 pathogenic variations are associated with a neurodevelopmental disorder characterized by spastic diplegia and visual defects (NEDSDV) [OMIM #615075], featuring psychomotor delay, intellectual disability, behavioral disturbances, movement disorders, visual defects and subtle facial and somatic features. We report on a new series of 19 NEDSDV patients (mean age 10.3 years), nine of whom bearing novel CTNNB1 variants. Notably, five patients showed congenital heart anomalies including absent pulmonary valve with intact ventricular septum, atrioventricular canal with hypoplastic aortic arch, tetralogy of Fallot, and mitral valve prolapse. We focused on the cardiac phenotype characterizing such cases and reviewed the congenital heart defects in previously reported NEDSDV patients. While congenital heart defects had occasionally been reported so far, the present findings configure a higher rate of cardiac anomalies, suggesting dedicated heart examination to NEDSDV clinical management.

Systematic ophthalmologic evaluation in cardio-facio-cutaneous syndrome: A genotype-endophenotype correlation.

Cardio-facio-cutaneous syndrome (CFCS) is a rare genetic disorder belonging to the RASopathies, a group of developmental syndromes caused by upregulated RAS/MAPK signaling. Pathogenic variants affecting four genes, KRAS, BRAF, MAP2K1 and MAP2K2, encoding core signal transducers of the pathway, underlie the condition. Major clinical features include a distinctive facies, ectodermal and cardiac anomalies, reduced postnatal growth, intellectual disability, and musculoskeletal abnormalities. Similar to other RASopathies, reports of visual impairment, high refractive error, optic nerve pallor, and other ocular abnormalities have been anecdotally reported in the literature. The aim of our study is to report the prevalence of ophthalmologic abnormalities in a large monocentric cohort of individuals affected by CFCS and explore the occurrence of genotype-endophenotype correlations in this series of patients. We observed that BRAF mutations are associated to a higher prevalence of anisometropia >3D (11.8% vs. 0%) and high astigmatism (29.4% vs. 0%; both p < 0.001) while patients with mutations in other genes had a significantly higher prevalence of myopia >6 D (60% vs. 5.9%; p = 0.012). Pale optic disc was associated with higher prevalence of inferior oblique muscle (IO) overaction (33.3% vs. 0%) and lower prevalence of ptosis (0% vs. 11.8%; both p < 0.001). Combined exotropia, IO overaction and nystagmus were frequent in patients with pale optic nerve. Our findings might suggest the need for earlier ophthalmologic referral for CFCS patients due to high risk of amblyopia, especially those expressing BRAF mutations.

Celiac disease prevalence and predisposing-HLA in a cohort of 93 Williams-Beuren syndrome patients.

Williams-Beuren syndrome is considered to be at increased risk for celiac disease, as for recent literature data and celiac disease guidelines, despite pathogenic mechanisms are still unclear. Our study analyzed the prevalence of autoimmune disorders, HLA DQ2 and/or DQ8 haplotypes, of transglutaminase antibodies and of diagnosis of celiac disease in a cohort of 93 Williams-Beuren syndrome's patients (mean age 21.26 years). Our study showed an increased prevalence of celiac disease equal to 10.8% (10/93 patients). We did not find a significant different frequency of predisposing HLA in subjects with Williams-Beuren syndrome compared to literature data in the general population (49.5% vs. 42.9%, with p > .1), nor a susceptibility to autoimmunity. This suggests that the increased prevalence of celiac disease in Williams-Beuren syndrome cannot be ascribed to HLA haplotype and may be related to other factors that still need to be identified in these patients.

Cross-cultural adaptation and validation of the Italian version of the Montreal Children's Hospital Feeding Scale in a special healthcare needs population.

BACKGROUND: The Montreal Children's Hospital Feeding Scale (MCH-FS) allows paediatricians and other health care professionals to identify feeding difficulties among children. AIM: To translate and adapt the MCH-FS into Italian, and to evaluate the validity and reliability of this Italian version of the Montreal Children's Hospital Feeding Scale (I-MCH-FS). METHODS & PROCEDURES: A total of 150 children with special healthcare needs were admitted to the Rare Disease Unit of the Paediatrics Department at the Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy, between March 2021 and March 2022 (74 males; mean age = 3.85 ± 1.96 years; median age = 4 years; age range = 6 months-6 years and 11 months) and 150 healthy participants (83 males; mean age = 3.5 ± 1.98 years; median age = 3 years; age range = 6 months-6 years and 11 months) were included in the study, which was approved by the local ethics committee. The original version of the MCH-FS was translated and cross-cultural adapted through five stages: (1) initial translation, (2) synthesis of the translations, (3) back translation, (4) expert committee and (5) test of the prefinal version. Test-retest reliability and internal consistency were assessed using Pearson r, Spearman r and Cronbach's alpha, respectively. Construct validity was established by comparing data obtained from patients with those of healthy participants using the Mann-Whitney U-test. OUTCOMES & RESULTS: A Pearson r of 0.98, a Spearman r of 0.95 and Cronbach's alpha value of 0.86 were obtained. In the clinical group, 40.6% children were classified as having feeding disorders (n = 61), while in the normative group 4.7% were diagnosed with feeding problems (n = 7). Mean total score of the clinical group was significatively different from the normative's. CONCLUSIONS & IMPLICATIONS: The I-MCH-FS is a valid and reliable one-page, quick screening tool used to identify feeding disorders among children with special needs in outpatient paediatric setting. WHAT THIS PAPER ADDS: What is already known on the subject The MCH-FS is a valid and reliable parent-report measure aimed at discriminating between children presenting or not feeding disorders. What this paper adds to existing knowledge This paper presents the translation and cross-cultural adaptation of the scale into the Italian language. What are the potential or actual clinical implications of this work? The Italian version of the MCH-FS can be used in the special healthcare needs population.

Validation and cross-cultural adaptation of the Italian version of the paediatric eating assessment tool (I-PEDI-EAT-10) in genetic syndromes.

BACKGROUND: The Pediatric Eating Assessment Tool (PEDI-EAT-10) is a reliable and valid tool for rapid identification of dysphagia in patients aged 18 months to 18 years. AIMS: To translate and adapt the PEDI-EAT-10 into the Italian language and evaluate its validity and reliability. METHODS & PROCEDURES: The translation and cross-cultural adaptation of the tool consisted of five stages: initial translation, synthesis of the translations, back translation, expert committee evaluation and test of the prefinal version. The internal consistency of the translated tool was analysed in a clinical group composed of 200 patients with special healthcare needs aged between 18 months and 18 years. They were consecutively enrolled at the Rare Disease Unit, Paediatrics Department, Fondazione Policlinico Agostino Gemelli-IRCCS, Rome. For test-retest reliability, 50 caregivers filled in the PEDI-EAT-10 questionnaire for a second time after a 2-week period. Construct validity was established by comparing data obtained from patients with data from healthy participants (n = 200). The study was approved by the local ethics committee. OUTCOMES & RESULTS: Psychometric data obtained from patients (104 M; mean age = 8.08 ± 4.85 years; median age = 7 years) showed satisfactory internal consistency (Cronbach's α = 0.89) and test-retest reliability (Pearson r = 0.99; Spearman r = 0.96). A total of 30% of children were classified as having a high risk of penetration/aspiration. The Italian PEDI-EAT-10 mean total score of the clinical group was significantly different from that resulting from healthy participants. CONCLUSIONS & IMPLICATIONS: The PEDI-EAT-10 was successfully translated into Italian, validated and found to be a reliable one-page rapid screening tool to identify dysphagia in children and adolescents with special needs. WHAT THIS PAPER ADDS: What is already known on the subject The PEDI-EAT-10 is a valid and reliable quick discriminative paediatric tool for identifying penetration/aspiration risks. What this paper adds to the existing knowledge In the present study we successfully translated and adapted the PEDI-EAT-10 into the Italian language. What are the potential or actual clinical implications of this work? This translation and adaptation increase access to valid feeding and swallowing assessment for children of Italian-speaking families. In addition, the I-PEDI-EAT-10 can suggest further assessment of patients' swallowing abilities.

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

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

Infantile epileptic spasms syndrome in children with cardiofaciocutanous syndrome: Clinical presentation and associations with genotype.

Gene variants that dysregulate signaling through the RAS-MAPK pathway cause cardiofaciocutaneous syndrome (CFCS), a rare multi-system disorder. Infantile epileptic spasms syndrome (IESS) and other forms of epilepsy are among the most serious complications. To investigate clinical presentation, treatment outcomes, and genotype-phenotype associations in CFCS patients with IESS, molecular genetics and clinical neurological history were reviewed across two large clinical research cohorts (n = 180). IESS presented in 18/180 (10%) cases, including 16 patients with BRAF variants and 2 with MAP2K1 variants. Among IESS patients with BRAF variants, 16/16 (100%) had sequence changes affecting the protein kinase domain (exons 11-16), although only 57% of total BRAF variants occurred in this domain. Clinical onset of spasms occurred at a median age of 5.4 months (range: 1-24 months). Among 13/18 patients whose IESS resolved with anti-seizure medications, 10 were treated with ACTH and/or vigabatrin. A substantial majority of CFCS patients with IESS subsequently developed other epilepsy types (16/18; 89%). In terms of neurodevelopmental outcomes, gross motor function and verbal communication were more limited in patients with a history of IESS compared to those without IESS. These findings can inform clinical neurological care guidelines for CFCS and development of relevant pre-clinical models for severe epilepsy phenotypes.

Elucidating the clinical spectrum and molecular basis of HYAL2 deficiency.

PURPOSE: We previously defined biallelic HYAL2 variants causing a novel disorder in 2 families, involving orofacial clefting, facial dysmorphism, congenital heart disease, and ocular abnormalities, with Hyal2 knockout mice displaying similar phenotypes. In this study, we better define the phenotype and pathologic disease mechanism. METHODS: Clinical and genomic investigations were undertaken alongside molecular studies, including immunoblotting and immunofluorescence analyses of variant/wild-type human HYAL2 expressed in mouse fibroblasts, and in silico modeling of putative pathogenic variants. RESULTS: Ten newly identified individuals with this condition were investigated, and they were associated with 9 novel pathogenic variants. Clinical studies defined genotype-phenotype correlations and confirmed a recognizable craniofacial phenotype in addition to myopia, cleft lip/palate, and congenital cardiac anomalies as the most consistent manifestations of the condition. In silico modeling of missense variants identified likely deleterious effects on protein folding. Consistent with this, functional studies indicated that these variants cause protein instability and a concomitant cell surface absence of HYAL2 protein. CONCLUSION: These studies confirm an association between HYAL2 alterations and syndromic cleft lip/palate, provide experimental evidence for the pathogenicity of missense alleles, enable further insights into the pathomolecular basis of the disease, and delineate the core and variable clinical outcomes of the condition.

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.

Smith Magenis syndrome: First case of congenital heart defect in a patient with Rai1 mutation.

Smith Magenis syndrome (SMS) is a rare neurobehavioral disorder caused by 17p11.2 microdeletion encompassing Retinoic Acid-Induced 1 (RAI1) gene (90% of cases) or by RAI1 point mutation (10% of cases). The neuropsychological phenotype of individuals with 17p11.2 deletion and in those with RAI1 variants mostly overlaps. However, cardiac defects have been described only in patients with a deletion so far. Here, we present the first case of a patient affected by SMS caused by RAI1 variant in whom a severe congenital pulmonary valve stenosis was diagnosed at birth, requiring trans catheter dilatation in the first month of life. This case expands the phenotypic spectrum associated with RAI1 variants in SMS, describing a previously unreported association with a congenital heart disease.

Prevalence of gastrointestinal disorders in individuals with RASopathies: May RAS/MAP/ERK pathway dysfunctions be a model of neuropathic pain and visceral hypersensitivity?

RASopathies are a group of neurodevelopmental syndromes caused by germline variants in genes of the Ras/MAP/ERK pathway. Growth failure, neurological involvement, and pain represent the main features of these conditions. ERK signaling cascade plays a crucial role in nociception and visceral pain and it is likely implicated in the genesis of neuropathic pain and maintenance of altered pain states. We studied the prevalence of abdominal pain and functional gastrointestinal (GI) disorders in a large sample of individuals with RASopathies. A brief pain inventory questionnaire and semi-structured dedicated interview were used to investigate presence and localization of pain. A Rome IV questionnaire was used to screen for functional GI disorders. Eighty patients with clinical and molecular diagnoses of RASopathy were recruited (42 with Noonan syndrome; 17 with Costello Syndrome and 21 with cardio-facio-cutaneous syndrome). Overall, the prevalence of abdominal pain was 44% and prevalence of functional GI disorders was 78% with constipation, abdominal pain, and aerophagia being the most frequently detected ones. A significant association was found between pain and irritable bowel syndrome, functional constipation and aerophagia. Children with RASopathies have a high prevalence of functional gastrointestinal disorders. These children could represent a good in vivo model to study neuropathic pain, visceral hypersensitivity and gut-brain axis disorders.

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.

Bone tissue homeostasis and risk of fractures in Costello syndrome: A 4-year follow-up study.

Costello syndrome (CS) is a neurodevelopmental disorder with a distinctive musculoskeletal phenotype and reduced bone mineral density (BMD) caused by activating de novo mutations in the HRAS gene. Herein, we report the results of a prospective study evaluating the efficacy of a 4-year vitamin D supplementation on BMD and bone health. A cohort of 16 individuals ranging from pediatric to adult age with molecularly confirmed CS underwent dosages of bone metabolism biomarkers (serum/urine) and dual-energy X-ray absorptiometry (DXA) scans to assess bone and body composition parameters. Results were compared to age-matched control groups. At baseline evaluation, BMD was significantly reduced (p ≤ 0.05) compared to controls, as were the 25(OH)vitD levels. Following the 4-year time interval, despite vitamin D supplementation therapy at adequate dosages, no significant improvement in BMD was observed. The present data confirm that 25(OH)vitD and BMD parameters are reduced in CS, and vitamin D supplementation is not sufficient to restore proper BMD values. Based on this evidence, routine monitoring of bone homeostasis to prevent bone deterioration and possible fractures in adult patients with CS is highly recommended.