Craniofacial and dental development in Costello syndrome

Skeletal defects and bone metabolism in Noonan, Costello and cardio-facio-cutaneous syndromes

Noonan, Costello and Cardio-facio-cutaneous syndromes belong to a group of disorders named RASopathies due to their common pathogenetic origin that lies on the Ras/MAPK signaling pathway. Genetics has eased, at least in part, the distinction of these entities as they are presented with overlapping clinical features which, sometimes, become more pronounced with age. Distinctive face, cardiac and skeletal defects are among the primary abnormalities seen in these patients. Skeletal dysmorphisms range from mild to severe and may include anterior chest wall anomalies, scoliosis, kyphosis, short stature, hand anomalies, muscle weakness, osteopenia or/and osteoporosis. Patients usually have increased serum concentrations of bone resorption markers, while markers of bone formation are within normal range. The causative molecular defects encompass the members of the Ras/MAPK/ERK pathway and the adjacent cascades, important for the maintenance of normal bone homeostasis. It has been suggested that modulation of the expression of specific molecules involved in the processes of bone remodeling may affect the osteogenic fate decision, potentially, bringing out new pharmaceutical targets. Currently, the laboratory imprint of bone metabolism on the clinical picture of the affected individuals is not clear, maybe due to the rarity of these syndromes, the small number of the recruited patients and the methods used for the description of their clinical and biochemical profiles.

Non-Plaque Induced Diffuse Gingival Overgrowth: An Overview

Non-plaque induced diffuse gingival overgrowth represents a broad class of conditions caused by several etiological factors. The aim of this review is to highlight the most recent updates and classifications of all the existent gingival overgrowths. In addition, we highlighted the diagnostic pathway that should be employed in patients affected by gingival overgrowth. Gingival overgrowth can be related to syndromic diseases including a wide spectrum of genetic and chromosomal alterations. However, thanks to scientific sharing and the availability of genetic panels it is possible to obtain an accurate phenotypic identification of well-known syndromes and also to identify new ones. This narrative review shows that through rigid, strict diagnostic protocols, the work of the clinician is greatly facilitated, despite the wide variety of pathologies considered. In conclusion, the exchange of specialists’ competencies and the multidisciplinary management of these patients, are crucial to reach diagnosis and the correct clinical-therapeutic management.

The RASopathies: from pathogenetics to therapeutics

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

RASopathies: The musculoskeletal consequences and their etiology and pathogenesis

The RASopathies comprise an ever-growing number of clinical syndromes resulting from germline mutations in components of the RAS/MAPK signaling pathway. While multiple organs and tissues may be affected by these mutations, this review will focus on how these mutations specifically impact the musculoskeletal system. Herein, we review the genetics and musculoskeletal phenotypes of these syndromes in humans. We discuss how mutations in the RASopathy syndromes have been studied in translational mouse models. Finally, we discuss how signaling molecules within the RAS/MAPK pathway are involved in normal and abnormal bone biology in the context of osteoblasts, osteoclasts and chondrocytes.

Phoniatric, Audiological, Orodental and Speech Problems in a Boy with Cardio-Facio-Cutaneous Syndrome Type 3 (CFC 3) Due to a Pathogenic Variant in MAP2K1 - Case Study

Cardio-facio-cutaneous syndrome 3 (CFC3) due to variants in MAP2K1 is a rare genetic disorder manifested mainly by short stature, facial dysmorphism, abnormalities of the cardiovascular system, skin changes, and intellectual disability. The aim of the study is the evaluation of the occurrence of pathological changes in the upper respiratory tract, orthodontic disorders, as well as voice, speech and hearing abnormalities in an 11-year-old boy with CFC3 syndrome. The lack of detailed diagnostics of speech, voice and hearing disorders, as well as the degree of their severity was an inspiration to undertake research in this field. Pathological changes in face, oral cavity, upper respiratory tract (nose, nasopharynx, larynx), and hearing organ, as well as voice and speech quality, were assessed in an 11-year-old boy with CFC3 syndrome. Pathologies of the upper respiratory tract (adenoid hypertrophy, narrowing of the nasal passages) and laryngeal asymmetry were found without significant changes in voice quality in the acoustic examination, except for the voice timbre change confirmed in narrowband spectrography. Complex audiological assessment confirmed the existence of bilateral sensorineural hearing loss. Speech pathology assessment revealed abnormalities in the structure of articulation organ, its decreased motor efficiency, imprecision, reduced coordination, as well as the presence of autistic features. Exome sequencing showed the heterozygous variant c.371C>T (p.Pro124Leu) in the MAP2K1 gene, previously described as pathogenic, thus supporting a causative relevance. Phoniatric, audiological, orodental and speech problems should be considered as features of cardio-facio-cutaneous syndrome type 3 (CFC 3) phenotype due to a pathogenic variant in MAP2K1.

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

Background

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

Methods and Results

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

Conclusion

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

Prevalence of malocclusions in children with microcephaly associated with the Zika virus

INTRODUCTION

The objectives of this study were to determine the prevalence of malocclusion among children with Zika virus-associated microcephaly (MZV) and to describe the most common malocclusion in this population.

METHODS

This was a cross-sectional study including patients aged between 30 and 36 months diagnosed with MZV. Healthy children were randomly selected with the same sociodemographic characteristics as the control group. Information about arch-type, primate spaces, arch form, overbite, overjet, midline deviation, anterior crossbite, anterior open bite, and the posterior crossbite was recorded. The statistical analysis used descriptive analysis, Pearson chi-square test, and multivariate logistic regression.

RESULTS

Forty children comprised the MZV group, and 40 comprised the control group. Our results demonstrated a significantly higher prevalence of malocclusions in children who had MZV than the control group (P <0.001). Patients with MZV were more likely to have late eruption (P <0.001), hypoplastic maxillary arch (P <0.001), hypoplastic mandibular arch (P <0.001), excessive overjet (P <0.001), and posterior crossbite (P = 0.004).

CONCLUSIONS

The prevalence of malocclusion was higher among children with MZV. Late eruption, hypoplastic maxillary arch, hypoplastic mandibular arch, excessive overjet, and posterior crossbite were the most common characteristics for this population.

Activated KCNQ1 channel promotes fibrogenic response in hereditary gingival fibromatosis via clustering and activation of Ras

BACKGROUND AND OBJECTIVE

Activated potassium channels were found to be strongly correlated with gingival overgrowth (GO) phenotype as we reviewed syndromic hereditary gingival fibromatosis (HGF). Nevertheless, the functional roles of potassium channels in gingival fibrosis or gingival overgrowth remained uncovered. The aim of the present study was to explore the pathogenic role of aberrantly activated potassium channel in Hereditary Gingival Fibromatosis (HGF).

METHODS

Gingival tissues were collected from 9 HGF patients and 15 normal controls. Expression of KCNQ1 was detected by immunohistochemistry. Gingival fibroblasts were isolated, and outward K⁺ currents were detected by whole-cell patch-clamp analysis, transmembrane potential was determined by flow cytometry. Normal human gingival fibroblasts (NHGFs) were transfected with KCNQ1 adenovirus or treated with KCNQ1 selective agonist ML277 and antagonist chromanol 293B. Accumulation of Extracellular Matrix (ECM) was measured by Western blotting and Sircol Soluble Collagen Assay. Content of secreted TGF-β1 was measured by ELISA. Active RAS pull-down assay and cell immunofluorescence were utilized to verify RAS activation.

RESULTS

KCNQ1 was upregulated in gingival tissues derived from HGF patients and HGF gingival fibroblasts presented increased outward K⁺ currents than NHGFs. Overexpression of KCNQ1, or KCNQ1 agonist ML277, promoted fibrotic responses of NHGFs. TGF-β1 and KCNQ1 channels formed a positive feed-back loop. ML277 generated lateral clustering and activation of Ras on plasma membrane, followed by augmented MAPK/AP-1 signaling pathway output. JNK or ERK1/2 inhibitors suppressed ML277-induced AP-1 and ECM upregulation.

CONCLUSION

Activation of KCNQ1 potassium channel promoted fibrogenic responses in NHGFs via Ras/MAPK/AP-1 signaling.

The duality of human oncoproteins: drivers of cancer and congenital disorders

Human oncoproteins promote transformation of cells into tumours by dysregulating the signalling pathways that are involved in cell growth, proliferation and death. Although oncoproteins were discovered many years ago and have been widely studied in the context of cancer, the recent use of high-throughput sequencing techniques has led to the identification of cancer-associated mutations in other conditions, including many congenital disorders. These syndromes offer an opportunity to study oncoprotein signalling and its biology in the absence of additional driver or passenger mutations, as a result of their monogenic nature. Moreover, their expression in multiple tissue lineages provides insight into the biology of the proto-oncoprotein at the physiological level, in both transformed and unaffected tissues. Given the recent paradigm shift in regard to how oncoproteins promote transformation, we review the fundamentals of genetics, signalling and pathogenesis underlying oncoprotein duality.

Syndromes with gingival fibromatosis: A systematic review

OBJECTIVE

The aim of systematic review was to describe the phenotypes and molecular profiles of syndromes with gingival fibromatosis (GF).

METHODS

A comprehensive search of PubMed, LILACS, Livivo, Scopus, and Web of Science was conducted using key terms relevant to the research questions and supplemented by a gray literature search. The Methodological Quality and Synthesis of Case Series and Case Reports in association with the Case Series and Prevalence Studies from the Joanna Briggs Institute critical appraisal tools were used for the risk of bias. We followed the PRISMA checklist guidelines.

RESULTS

Eighty-four studies reporting GF as an oral manifestation of a syndrome were identified in this review. Enamel renal syndrome was the most frequently reported syndrome with GF, represented by 54 individuals in 19 studies, followed by Zimmermann-Laband syndrome with 24 individuals in 15 studies and Costello syndrome, which was presented in a case series study with 41 individuals. Among reported cases, other clinical manifestations such as hypertrichosis, ectopic gingival calcification, and cherubism were described.

CONCLUSIONS

The results emphasize the need of systematic oro-dental-facial phenotyping for future descriptions as well as further molecular analysis in order to better understand the occurrence of syndromic GF.

Nonsyndromic hereditary gingival fibromatosis: Characterization of a family and review of genetic etiology

Our aim is to describe a family with a nonsyndromic form of hereditary gingival fibromatosis (HGF) and discuss genetic characteristics of this rare disease by reviewing reported cases. A mother and three descendants were diagnosed with HGF. There was marked variable expressivity: from severe generalized gingival overgrowth in a 16-year-old boy (the proband) to minimal manifestations in the mother. The proband was submitted to gingivectomy and gingivoplasty. In younger siblings, the disease remained stable for 5 years, suggesting that clinical surveillance is a good option. The diagnosis was supported by histopathological examination. Analysis of this family and literature-reported cases supports that HGF most frequently shows an autosomal dominant inheritance with high penetrance and variable expressivity. Neomutations and gonadal mosaicism do not seem to be a rare event. Although five loci have been mapped by linkage analysis, only two genes, SOS1 and REST, were identified in four families.

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.

Craniofacial, orofacial and dental disorders: the role of the RAS/ERK pathway

Deviations from the precisely coordinated programme of human head development can lead to craniofacial and orofacial malformations often including a variety of dental abnormalities too. Although the aetiology is still unknown in many cases, during the last decades different intracellular signalling pathways have been genetically linked to specific disorders. Among these pathways, the RAS/extracellular signal-regulated kinase (ERK) signalling cascade is the focus of this review since it encompasses a large group of genes that when mutated cause some of the most common and severe developmental anomalies in humans. We present the components of the RAS/ERK pathway implicated in craniofacial and orodental disorders through a series of human and animal studies. We attempt to unravel the specific molecular targets downstream of ERK that act on particular cell types and regulate key steps in the associated developmental processes. Finally we point to ambiguities in our current knowledge that need to be clarified before RAS/ERK-targeting therapeutic approaches can be implemented.

A review of craniofacial and dental findings of the RASopathies

OBJECTIVES

The RASopathies are a group of syndromes that have in common germline mutations in genes that encode components of the Ras/mitogen-activated protein kinase (MAPK) pathway and have been a focus of study to understand the role of this pathway in development and disease. These syndromes include Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NSML or LEOPARD syndrome), neurofibromatosis type 1 (NF1), Costello syndrome (CS), cardio-facio-cutaneous (CFC) syndrome, neurofibromatosis type 1-like syndrome (NFLS or Legius syndrome) and capillary malformation-arteriovenous malformation syndrome (CM-AVM). These disorders affect multiple systems, including the craniofacial complex. Although the craniofacial features have been well described and can aid in clinical diagnosis, the dental phenotypes have not been analysed in detail for each of the RASopathies. In this review, we summarize the clinical features of the RASopathies, highlighting the reported craniofacial and dental findings.

METHODS

Review of the literature.

RESULTS

Each of the RASopathies reviewed, caused by mutations in genes that encode different proteins in the Ras pathway, have unique and overlapping craniofacial and dental characteristics.

CONCLUSIONS

Careful description of craniofacial and dental features of the RASopathies can provide information for dental clinicians treating these individuals and can also give insight into the role of Ras signalling in craniofacial development.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Oro-dental features of Pallister-Killian syndrome: Evaluation of 21 European probands

Pallister-Killian syndrome (PKS) is a rare sporadic multi-systemic developmental disorder caused by a mosaic tetrasomy of the short arm of chromosome 12. A wide range of clinical characteristics including intellectual disability, seizures, and congenital malformations has previously been described. Individuals with PKS show a characteristic facial phenotype with frontal bossing, alopecia, sparse eyebrows, depressed nasal bridge, long philtrum, telecanthus, and posteriorly rotated ears. Oro-dental features, such as "Pallister lip," macroglossia, delayed eruption of primary teeth, high arched-palate, prognathism, and cleft palate have been occasionally reported in the medical literature. The aim of the study was to assess the oro-dental phenotype of PKS and to describe the oral health status in a cohort participating in the First European Workshop on PKS. A clinical dental examination was performed in 21 Caucasian probands and data regarding medical and dental history collected. Twelve probands (57%) showed an atypical dental pattern, with multiple missing teeth (primarily the first permanent molars) and 2 (10%) a double teeth. The severity of gingivitis and dental caries increased with age and gingival overgrowth was a common finding. A characteristic occlusive phenotype was found: a high-arched palate with mandibular prognathism associated with an anterior openbite and crossbite and with posterior crossbite (unilateral or bilateral). The prevalence of oral habits (non-nutritive sucking, mouth breathing, bruxism) was high, even in older probands. This study suggests that individuals affected by PKS should be observed closely for oro-dental diseases and a multidisciplinary approach is needed to implement the right preventive measures. © 2016 Wiley Periodicals, Inc.

Modeling craniofacial and skeletal congenital birth defects to advance therapies

Craniofacial development is an intricate process of patterning, morphogenesis, and growth that involves many tissues within the developing embryo. Genetic misregulation of these processes leads to craniofacial malformations, which comprise over one-third of all congenital birth defects. Significant advances have been made in the clinical management of craniofacial disorders, but currently very few treatments specifically target the underlying molecular causes. Here, we review recent studies in which modeling of craniofacial disorders in primary patient cells, patient-derived induced pluripotent stem cells (iPSCs), and mice have enhanced our understanding of the etiology and pathophysiology of these disorders while also advancing therapeutic avenues for their prevention.

From Bench to Bedside and Back: Improving Diagnosis and Treatment of Craniofacial Malformations Utilizing Animal Models

Craniofacial anomalies are among the most common birth defects and are associated with increased mortality and, in many cases, the need for lifelong treatment. Over the past few decades, dramatic advances in the surgical and medical care of these patients have led to marked improvements in patient outcomes. However, none of the treatments currently in clinical use address the underlying molecular causes of these disorders. Fortunately, the field of craniofacial developmental biology provides a strong foundation for improved diagnosis and for therapies that target the genetic causes of birth defects. In this chapter, we discuss recent advances in our understanding of the embryology of craniofacial conditions, and we focus on the use of animal models to guide rational therapies anchored in genetics and biochemistry.