Human Genetics of Atrial Septal Defect.

Although atrial septal defects (ASD) can be subdivided based on their anatomical location, an essential aspect of human genetics and genetic counseling is distinguishing between isolated and familiar cases without extracardiac features and syndromic cases with the co-occurrence of extracardiac abnormalities, such as developmental delay. Isolated or familial cases tend to show genetic alterations in genes related to important cardiac transcription factors and genes encoding for sarcomeric proteins. By contrast, the spectrum of genes with genetic alterations observed in syndromic cases is diverse. Currently, it points to different pathways and gene networks relevant to the dysregulation of cardiomyogenesis and ASD pathogenesis. Therefore, this chapter reflects the current knowledge and highlights stable associations observed in human genetics studies. It gives an overview of the different types of genetic alterations in these subtypes, including common associations based on genome-wide association studies (GWAS), and it highlights the most frequently observed syndromes associated with ASD pathogenesis.

Obstetrical and neonatal outcomes of cardio-facio-cutaneous syndrome: Prenatal consequences of Ras/MAPK dysregulation.

We systematically delineated the prenatal phenotype, and obstetrical and neonatal outcomes of the RASopathy cardio-facio-cutaneous (CFC) syndrome. A comprehensive, retrospective medical history survey was distributed to parents of children with confirmed CFC in collaboration with CFC International, Inc. Data were collected on CFC gene variant, maternal characteristics, pregnancy course, delivery, and neonatal outcomes with the support of medical records. We identified 43 individuals with pathogenic variants in BRAF (81%), MEK1 (14%), or MEK2 (5%) genes. The median age was 8.5 years. Hyperemesis gravidarum, gestational diabetes, gestational hypertension, and preeclampsia occurred in 5/43 (12%), 4/43 (9%), 3/43 (7%), and 3/43 (7%) of pregnancies, respectively. Second and third trimester ultrasound abnormalities included polyhydramnios, macrocephaly, macrosomia, and renal and cardiac abnormalities. Delivery occurred via spontaneous vaginal, operative vaginal, or cesarean delivery in 15/42 (36%), 7/42 (16%), and 20/42 (48%), respectively. Median gestational age at delivery was 37 weeks and median birth weight was 3501 grams. Germline pathogenic vaiants had mutiple congenital consequences including polyhydramnios, renal and cardiac abnormalities, macrosomia, and macrocephaly on second and third trimester ultrasound. Elevated rates of operative delivery and neonatal complications were also noted. Understanding and defining a prenatal phenotype may improve prenatal prognostic counseling and outcomes.

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.

Cancer-causing MAP2K1 mutation in a mosaic patient with cardio-facio-cutaneous syndrome and immunodeficiency.

RASopathies are disorders caused by germline mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. These syndromes share features of developmental delay, facial dysmorphisms, and defects in various organs, as well as cancer predisposition. Somatic mutations of the same pathway are one of the primary causes of cancer. It is thought that germline cancer-causing mutations would be embryonic lethal, as a more severe phenotype was shown in Drosophila and zebrafish embryos with cancer MAP2K1 mutations than in those with RASopathy mutations. Here we report the case of a patient with RASopathy caused by a cancer-associated MAP2K1 p.Phe53Leu mutation. The postzygotic mosaic nature of this mutation could explain the patient's survival.

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.

Characterization of bone homeostasis in individuals affected by cardio-facio-cutaneous syndrome.

Cardio-facio-cutaneous syndrome (CFCS) is a rare disorder characterized by distinctive craniofacial appearance, cardiac, neurologic, cutaneous, and musculoskeletal abnormalities. It is due to heterozygous mutations in BRAF, MAP2K1, MAP2K2, and KRAS genes, belonging to the RAS/MAPK pathway. The role of RAS signaling in bone homeostasis is highly recognized, but data on bone mineral density (BMD) in CFCS are lacking. In the present study we evaluated bone parameters, serum and urinary bone metabolites in 14 individuals with a molecularly confirmed diagnosis of CFCS. Bone assessment was performed through dual X-ray absorptiometry (DXA); height-adjusted results were compared to age- and sex-matched controls. Blood and urinary bone metabolites were also analyzed and compared to the reference range. Despite vitamin D supplementation and almost normal bone metabolism biomarkers, CFCS patients showed significantly decreased absolute values of DXA-assessed subtotal and lumbar BMD (p ≤ 0.05), compared to controls. BMD z-scores and t-scores (respectively collected for children and adults) were below the reference range in CFCS, while normal in healthy controls. These findings confirmed a reduction in BMD in CFCS and highlighted the importance of monitoring bone health in these affected individuals.

Fibrous dysplasia in cardio-facio-cutaneous syndrome: A case report and review of literature.

Cardio-facio-cutaneous (CFC) syndrome (OMIM #:115150, 615278, 615279, 615280) is a rare genetic condition caused by variants in the RAS/mitogen-activated protein kinase (MAPK) signal transduction pathway. Up to 75% of cases are caused by mutations in the BRAF gene, whereas KRAS gene mutation has only been reported in <2% of cases. CFC syndrome is characterized by cardiac abnormalities, distinctive craniofacial dysmorphism, and various cutaneous abnormalities. Musculoskeletal and orthopedic manifestations are also prevalent in patients with CFC syndrome, among which the most common are skeletal deformities and joint laxities. Dysplastic bone disorders, on the other hand, have not been reported in CFC syndrome before. We report on a case of symmetrical polyostotic fibrous dysplasia (FD) in a patient with CFC syndrome with the KRAS(NM_004985.5):c.57G>C; p.Leu19Phe variant. The FDs were incidentally picked up, and patient was conservatively managed and remained asymptomatic on follow-up. The same variant was reported previously in a patient with Oculoectodermal Syndrome (OES), who developed polyostotic non-ossifying fibroma (NOF). This case explores FD as a possible new clinical feature of CFC syndrome, and when linked to the historical case of OES, explores whether the KRAS(NM_004985.5):c.57G>C; p.Leu19Phe mutation may potentially contribute to the development of dysplastic bone lesions in patients with this particular mutation.

Brain structural changes in patients with cardio-facio-cutaneous syndrome: effects of BRAF gene mutation and epilepsy on brain development. A case-control study by quantitative magnetic resonance imaging.

PURPOSE: To evaluate the brain volumetric changes caused by BRAF gene mutation in non-epileptic CFC patients and the influence of the age of epilepsy onset on brain development in 2 cohorts of epileptic CFC patients. METHODS: We enrolled CFC patients carrying BRAF gene mutations without epilepsy (4 patients) and with epilepsy (16 patients). CFC epileptic patients were divided into two cohorts based on the age of seizure onset: early-age onset (7 children) and late-age onset (9 adolescents). All three cohorts of patients underwent 3D FSPGR T1-weighted imaging to assess supratentorial and infratentorial brain volumes. Moreover, for each compartment, gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) volumes were measured. All measurements were compared with those of age-matched controls without neuroimaging abnormalities. RESULTS: All CFC patients showed supratentorial and infratentorial WM reduction and supratentorial ventricular enlargement (p < 0.01). However, patients with early age of epilepsy onset, compared with the other two cohorts of CFC patients, showed both GM and a more pronounced WM volume reduction (p < 0.01). CONCLUSION: In non-epileptic CFC children, we demonstrated WM volumetric reduction suggesting a direct effect of BRAF gene mutation on brain development. Nevertheless, in CFC epileptic patients, the age of epilepsy onset may contribute to brain atrophy. Brain atrophy in CFC patients, in part due to the natural history of the disease, may be worsened by epilepsy when it begins in the early ages because of interference with brain growth at that critical age of development.

Familial cardio-facio-cutaneous syndrome: Vertical transmission of the BRAF p.G464R pathogenic variant and review of the literature.

Cardio-facio-cutaneous syndrome (CFC) is one of the RASopathies and is caused by germline mutations that activate the Ras/mitogen-activated protein kinase (MAPK) pathway. CFC is due to heterozygous germline mutations in protein kinases BRAF, MEK1, or MEK2 and rarely in KRAS, a small GTPase. CFC is a multiple congenital anomaly disorder in which individuals may have craniofacial dysmorphia, heart issues, skin and hair anomalies, and delayed development. Pathogenic variants for CFC syndrome are usually considered de novo because vertical transmission has only been reported with MEK2 and KRAS. The index case was a 3-year-old male with features consistent with the clinical diagnosis of CFC. Sequencing revealed a previously reported heterozygous likely pathogenic variant BRAF p.G464R. Upon detailed family history, the index case's pregnant mother was noted to have similar features to her son. Targeted familial testing of the BRAF pathogenic variant was performed on the mother, confirming her diagnosis. Prenatal genetic testing for the fetus was declined, but postnatal molecular testing of the index case's sister was positive for the familial BRAF p.G464R variant. Functional analysis of the variant demonstrated increased kinase activity. We report the first identified vertically transmitted functional BRAF pathogenic variant. Our findings emphasize the importance of obtaining a comprehensive evaluation of family members and that activating pathogenic variants within the canonical MAPK cascade mediated by BRAF are compatible with human reproduction.

Cardio-facio-cutaneous syndrome with BRAF gene mutation: A case report and literature review. / BRAFåŸºå› çªå˜æ‰€è‡´å¿ƒ-面-皮肤综合征1ä¾‹å¹¶æ–‡çŒ®å¤ä¹ .

Cardio-facio-cutaneous (CFC) syndrome is an extremely rare autosomal dominant genetic disease due to BRAF and other gene mutations. The main characteristics of the patients are craniofacial deformities, cardiac malformations, skin abnormalities, delay of language and motor development, gastrointestinal dysfunction, intellectual disability, and epilepsy. In this case, the child has a typical CFC syndrome face and developmental delay. The gene results of the second-generation sequencing technology showed that there was a mutation site c.1741A>G (p. Asn581Asp) (heterozygous) in exon 14 of the BRAF (NM_004333.5) gene. The mutation was not observed in the child's parents. The above-mentioned mutation may be a de novo mutation. There is no effective therapy for this disease so far.

The sixth international RASopathies symposium: Precision medicine-From promise to practice.

The RASopathies are a group of genetic disorders that result from germline pathogenic variants affecting RAS-mitogen activated protein kinase (MAPK) pathway genes. RASopathies share RAS/MAPK pathway dysregulation and share phenotypic manifestations affecting numerous organ systems, causing lifelong and at times life-limiting medical complications. RASopathies may benefit from precision medicine approaches. For this reason, the Sixth International RASopathies Symposium focused on exploring precision medicine. This meeting brought together basic science researchers, clinicians, clinician scientists, patient advocates, and representatives from pharmaceutical companies and the National Institutes of Health. Novel RASopathy genes, variants, and animal models were discussed in the context of medication trials and drug development. Attempts to define and measure meaningful endpoints for treatment trials were discussed, as was drug availability to patients after trial completion.

A rare coincidence: the long QT syndrome and cardio-facio-cutaneous syndrome.

Cardio-facio-cutaneous syndrome is a genetic anomaly characterised by craniofacial dysmorphia, developmental retardation, skin lesions, mental retardation/learning disability, and cardiac malformations. Cardio-facio-cutaneous syndrome rarely causes arrhythmias and has not been previously associated with long QT in the literature. With this report, it was aimed to draw attention to a different presentation of the long QT syndrome.

MAP2K2 mutation as a cause of cardio-facio-cutaneous syndrome in an infant with a severe and fatal course of the disease.

Cardio-facio-cutaneous syndrome (CFCS), a rare congenital disorder of RASopathies, displays high phenotypic variability. Complications during pregnancy and in the perinatal period are commonly reported. Polyhydramnios is observed in over half of pregnancies and might occur with fetal macrocephaly, macrosomia, and/or heart defects. Premature birth is not uncommon and any complications like respiratory insufficiency, edema, and feeding difficulties are present and might delay accurate clinical diagnosis. Besides neonatal complications, CFCS newborns and later infants have distinctive dysmorphic features usually accompanied by neurological (hypotonia with motor delay, neurocognitive delay) findings. Also, heart defects usually present at birth. Herein, we present the case of a female baby born prematurely from a pregnancy complicated with polyhydramnios, presenting at birth with craniofacial features typical for RASopathies, heart defects, neurological abnormalities, and hyperkeratosis unusual for a neonatal period. Due to the presence of a heart defect and other complications related to premature birth, the course of the disease was severe with a fatal outcome at the age of 9 months. The RASopathy, particularly CFCS, clinical diagnosis was confirmed and de novo p.Phe57Ile mutation in MAP2K2 was identified.

Proceedings of the fifth international RASopathies symposium: When development and cancer intersect.

This report summarizes and highlights the fifth International RASopathies Symposium: When Development and Cancer Intersect, held in Orlando, Florida in July 2017. The RASopathies comprise a recognizable pattern of malformation syndromes that are caused by germ line mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. Because of their common underlying pathogenetic etiology, there is significant overlap in their phenotypic features, which includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, gastrointestinal and ocular abnormalities, neurological and neurocognitive issues, and a predisposition to cancer. The RAS pathway is a well-known oncogenic pathway that is commonly found to be activated in somatic malignancies. As in somatic cancers, the RASopathies can be caused by various pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. As such, the RASopathies represent an excellent model of study to explore the intersection of the effects of dysregulation and its consequence in both development and oncogenesis.

Craniosynostosis in patients with RASopathies: Accumulating clinical evidence for expanding the phenotype.

RASopathies are phenotypically overlapping genetic disorders caused by dysregulation of the RAS/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include Noonan syndrome, cardio-facio-cutaneous (CFC) syndrome, Costello syndrome, Neurofibromatosis type 1, Legius syndrome, Noonan syndrome with multiple lentigines, Noonan-like syndrome, hereditary gingival fibromatosis, and capillary malformation/arteriovenous malformation syndrome. Recently, six patients with craniosynostosis and Noonan syndrome involving KRAS mutations were described in a review, and a patient with craniosynostosis and Noonan syndrome involving a SHOC2 mutation has also been reported. Here, we describe patients with craniosynostosis and Noonan syndrome due to de novo mutations in PTPN11 and patients with craniosynostosis and CFC syndrome due to de novo mutations in BRAF or KRAS. All of these patients had cranial deformities in addition to the typical phenotypes of CFC syndrome and Noonan syndrome. In RASopathy, patients with cranial deformities, further assessments may be necessary to look for craniosynostosis. Future studies should attempt to elucidate the pathogenic mechanism responsible for craniosynostosis mediated by the RAS/MAPK signaling pathway.

New Mutations Associated with Rasopathies in a Central European Population and Genotype-Phenotype Correlations.

We performed the genetic analysis of Rasopathy syndromes in patients from Central European by direct sequencing followed by next generation sequencing of genes associated with Rasopathies. All 51 patients harboured the typical features of Rasopathy syndromes. Thirty-five mutations were identified in the examined patients (22 in PTPN11, two in SOS1, one in RIT1, one in SHOC2, two in HRAS, three in BRAF, two in MAP2K1 and two in the NF1 gene). Two of them (p.Gly392Glu in the BRAF gene and p.Gln164Lys in the MAP2K1 gene) were novel with a potentially pathogenic effect on the structure of these proteins. Statistically significant differences in the presence of pulmonary stenosis (63.64% vs. 23.81%, P = 0.013897) and cryptorchidism (76.47% vs. 30%, P = 0.040224) were identified as the result of comparison of the prevalence of phenotypic features in patients with the phenotype of Noonan syndrome and mutation in the PTPN11 gene, with the prevalence of the same features in patients without PTPN11 mutation. Cryptorchidism as a statistically significant feature in our patients with PTPN11 mutation was not reported as significant in other European countries (Germany, Italy and Greece). The majority of mutations were clustered in exons 3 (45.45%), 8 (22.73%), and 13 (22.73%) of the PTPN11 gene.

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.

Prenatal findings in cardio-facio-cutaneous syndrome.

Our study was designed to analyze prenatal manifestations in patients affected with cardio-facio-cutaneous syndrome (CFCS), in order to define indications of DNA testing in utero. Prenatal features were extracted from a national database and additional data were collected from 16 families contacted through the French association of CFC-Costello syndrome. We collected results of ultrasound scan (USS) biometrics, presence of congenital birth defects, and polyhydramnios. From the database, increased nuchal translucency was present in 13% of pregnancies, polyhydramnios in 52%, macrosomia and/or macrocephaly in 16%. Of the 16 pregnancies, 81% were complicated by abnormal USS findings. Polyhydramnios was reported in 67%. Head circumference, biparietal diameter, and abdominal circumference were above the 90th centile in 72%, 83% and, 81% of fetuses, respectively. Contrasting with macrosomia, femur length was below the 10th centile in 38%. Urinary tract abnormalities were found in 47% of fetuses. Most CFCS fetuses showed a combination of macrocephaly, macrosomia, and polyhydramnios, contrasting with relatively short femora. This growth pattern is also seen in Costello syndrome. We suggest that screening for CFCS and Costello gene mutations could be proposed in pregnancies showing this unusual pattern of growth parameters.

Cardiac Manifestations and Associations with Gene Mutations in Patients Diagnosed with RASopathies.

RASopathies are a group of syndromes caused by germline mutations of the RAS/MAPK pathway. They include Noonan syndrome, cardio-facio-cutaneous syndrome, Costello syndrome, and Noonan syndrome with multiple lentigines, which share many characteristic features including cardiac abnormalities. Here, we retrospectively reviewed the clinical manifestations and evaluated the genotype-phenotype associations with special focus on cardiac lesions of the patients with RASopathies. Cardiac symptoms were the most common initial presentation (27 %), except for admission to neonatal intensive care. Although there was a significant gap between the first visit to the hospital and the diagnosis of the genetic syndrome (19.9 ± 39.1 months), the age at the clinical diagnosis of the genetic syndrome was significantly lower in patients with CHD than in patients without CHD (47.26 ± 67.42 vs. 86.17 ± 85.66 months, p = 0.005). A wide spectrum of cardiac lesions was detected in 76.1 % (118/155) of included patients. The most common lesion was pulmonary stenosis, followed by atrial septal defect and hypertrophic cardiomyopathy (HCMP). About half of the pulmonary stenosis and HCMP patients progressed during the median follow-up period of 109.9 (range 9.7-315.4) months. Early rapid aggravation of cardiac lesions was linked to poor prognosis. MEK1, KRAS, and SOS1 mutations tend to be highly associated with pulmonary stenosis. Cardiologists may play important roles in early detection and diagnosis of RASopathies as well as associated CHDs. Due to the variety of clinical presentations and their progression of severity, proper management with regular long-term follow-up of these patients is essential.

The third international meeting on genetic disorders in the RAS/MAPK pathway: towards a therapeutic approach.

"The Third International Meeting on Genetic Disorders in the RAS/MAPK Pathway: Towards a Therapeutic Approach" was held at the Renaissance Orlando at SeaWorld Hotel (August 2-4, 2013). Seventy-one physicians and scientists attended the meeting, and parallel meetings were held by patient advocacy groups (CFC International, Costello Syndrome Family Network, NF Network and Noonan Syndrome Foundation). Parent and patient advocates opened the meeting with a panel discussion to set the stage regarding their hopes and expectations for therapeutic advances. In keeping with the theme on therapeutic development, the sessions followed a progression from description of the phenotype and definition of therapeutic endpoints, to definition of genomic changes, to identification of therapeutic targets in the RAS/MAPK pathway, to preclinical drug development and testing, to clinical trials. These proceedings will review the major points of discussion.