Case report: Noonan syndrome with multiple giant cell lesions and review of the literature

New Insights Into the Spectrum of RASopathies: Clinical and Genetic Data in a Cohort of 121 Spanish Patients

Noonan syndrome and related disorders are a group of well-known genetic conditions caused by dysregulation of the Ras/mitogen-activated protein kinase (RAS/MAPK) pathway. Because of the overlap of clinical and molecular features, they are now called RASopathies. In this study, we retrospectively analyzed the clinical data of 121 patients with a molecularly confirmed diagnosis of RASopathy, describing frequencies for clinical features in all organ systems as well as molecular data. The most common clinical diagnosis was Noonan Syndrome and the most frequently affected gene was PTPN11 followed by SOS1, RAF1, LZTR1, and RIT1. All patients had distinctive craniofacial features indicative of the RASopathy spectrum but we report some atypical features regarding craniofacial shape, such as craniosynostosis and microcephaly. We also describe uncommon clinical characteristics such as aortic dilation, multivalvular heart disease, abnormalities of the posterior fossa, and uterine congenital anomalies in female patients. Furthermore, the presence of multiple giant cell granulomas was observed specifically in patients with SOS1 variants. This comprehensive evaluation allows broadening the phenotypic spectrum of our population and their correlation with the genotype, which are essential to improve the recognition and the follow up of RASopathies as a multisystemic disease.

Craniomaxillofacial Fibro-osseous Lesions in Children

Craniofacial fibro-osseous lesions represent a diverse spectrum of pathologic conditions where fibrous tissue replaces healthy bone, resulting in the formation of irregular, woven bone. They are more commonly diagnosed in young people, with treatment strategies dependent on clinical behavior and skeletal maturity. This article discusses the examples of craniofacial fibro-osseous lesions, based on the latest classifications, along with their diagnostic criteria and management.

Craniofacial disorders and dysplasias: Molecular, clinical, and management perspectives

There is a wide spectrum of craniofacial bone disorders and dysplasias because embryological development of the craniofacial region is complex. Classification of craniofacial bone disorders and dysplasias is also complex because they exhibit complex clinical, pathological, and molecular heterogeneity. Most craniofacial disorders and dysplasias are rare but they present an array of phenotypes that functionally impact the orofacial complex. Management of craniofacial disorders is a multidisciplinary approach that involves the collaborative efforts of multiple professionals. This review provides an overview of the complexity of craniofacial disorders and dysplasias from molecular, clinical, and management perspectives.

Association between pectus excavatum and congenital genetic disorders: A systematic review and practical guide for the treating physician

BACKGROUND

Pectus excavatum (PE) could be part of a genetic disorder, which then has implications regarding comorbidity, the surgical correction of PE, and reproductive choices. However, referral of a patient presenting with PE for genetic analysis is often delayed because additional crucial clinical signs may be subtle or even missed in syndromic patients. We reviewed the literature to inventory known genetic disorders associated with PE and create a standardized protocol for clinical evaluation.

METHODS

A systematic literature search was performed in electronic databases. Genetic disorders were considered associated with PE if studies reported at least five cases with PE. Characteristics of each genetic disorder were extracted from the literature and the OMIM database in order to create a practical guide for the clinician.

RESULTS

After removal of duplicates from the initial search, 1632 citations remained. Eventually, we included 119 full text articles, representing 20 different genetic disorders. Relevant characteristics and important clinical signs of each genetic disorder were summarized providing a standardized protocol in the form of a scoring list. The most important clinical sign was a positive family history for PE and/or congenital heart defect.

CONCLUSIONS

Twenty unique genetic disorders have been found associated with PE. We have created a scoring list for the clinician that systematically evaluates crucial clinical signs, thereby facilitating decision making for referral to a clinical geneticist.

Multiple versus solitary giant cell lesions of the jaw: Similar or distinct entities?

The majority of giant cell lesions of the jaw present as a solitary focus of disease in bones of the maxillofacial skeleton. Less frequently they occur as multifocal lesions. This raises the clinical dilemma if these should be considered distinct entities and therefore each need a specific therapeutic approach. Solitary giant cell lesions of the jaw present with a great diversity of symptoms. Recent molecular analysis revealed that these are associated with somatic gain-of-function mutations in KRAS, FGFR1 or TRPV4 in a large component of the mononuclear stromal cells which all act on the RAS/MAPK pathway. For multifocal lesions, a small group of neoplastic multifocal giant cell lesions of the jaw remain after ruling out hyperparathyroidism. Strikingly, most of these patients are diagnosed with jaw lesions before the age of 20 years, thus before the completion of dental and jaw development. These multifocal lesions are often accompanied by a diagnosis or strong clinical suspicion of a syndrome. Many of the frequently reported syndromes belong to the so-called RASopathies, with germline or mosaic mutations leading to downstream upregulation of the RAS/MAPK pathway. The other frequently reported syndrome is cherubism, with gain-of-function mutations in the SH3BP2 gene leading through assumed and unknown signaling to an autoinflammatory bone disorder with hyperactive osteoclasts and defective osteoblastogenesis. Based on this extensive literature review, a RAS/MAPK pathway activation is hypothesized in all giant cell lesions of the jaw. The different interaction between and contribution of deregulated signaling in individual cell lineages and crosstalk with other pathways among the different germline- and non-germline-based alterations causing giant cell lesions of the jaw can be explanatory for the characteristic clinical features. As such, this might also aid in the understanding of the age-dependent symptomatology of syndrome associated giant cell lesions of the jaw; hopefully guiding ideal timing when installing treatment strategies in the future.

Dental and maxillofacial features of Noonan Syndrome: Case series of ten patients

Noonan syndrome (NS) is a relatively common congenital multiple-anomaly syndrome, resembling Turner syndrome, but without chromosomal anomaly. Besides the unusual facies, the maxillofacial and dental features of patients with NS are not well-summarized in the literature. The aim of this study was to describe these features and propose specific treatment guidelines for practitioners involved in oral and maxillofacial care. A retrospective multicentric study was conducted of 14 patients who were referred for NS screening. In total, 10 patients were found to carry a mutation involved in NS or NS-related disorders. Fifty percent of the mutations affected PTPN11. All patients presented with the typical extraoral features, such as macrocephaly, hypertelorism, ptosis, triangular face shape and ear dystrophy. Intraoral manifestations, including malocclusion (maxillary transversal deficiency, crossbite, anterior open-bite and class II malocclusion), dental anomalies (delayed eruption, agenesis and dystrophy, odontoma) and radiologic jaw lesions were identified in five out of 10 patients. These findings were searched in a review of the literature to obtain a comprehensive description of oral and maxillofacial features in patients with NS. The proposed treatment guidelines emphasize frequent coagulation anomalies that need to be considered prior to surgery. Early dental assessment and yearly follow-up with oral prophylaxis are recommended. Orthodontics and orthognathic surgery are also of primary importance in the management of NS patients.

Noonan syndrome with multiple Giant cell lesions, management and treatment with surgery and interferon alpha-2a therapy: Case report

We report the case of a 14-year-old girl that was referred to the maxillo facial surgery unit at age 11 years because she exhibited swelling in the right side of her maxilla and right mandible. After a conservative surgery, she started with interferon alpha-2a to avoid recurrence. She has remained in treatment with successful results during her follow up. Considerable reduction of both maxilla and mandible lesions and bone fill have been documented. In addition, her clinical history and phenotype were suggestive of Noonan syndrome. She has short stature, broad and short neck; hypertelorism (increased distance between the eyes); downslanting palpebral fissures; sparse eyebrows and eyelashes; posteriorly rotated ears with fleshy lobes; follicular keratosis over the face, and developmental delay. Her karyotype was 46, XX. Molecular analysis of RAS/MAPK pathway genes showed a SOS1 amino acid substitution of arginine to lysine at position 552 (p.R552K). This case presents the infrequent condition of Noonan syndrome with multiple giant cell lesions (NS/MGCL) that would be the first patient as far as we know treated with surgery and interferon alpha-2a for her giant cell lesions.

Chondroblastoma-like mass of the temporal bone, secondary aneurysmal bone cyst, and intracerebral hemorrhage in a patient with cardiofaciocutaneous syndrome: case report

Cardiofaciocutaneous syndrome (CFCS) is a rare developmental disorder that is phenotypically similar to Noonan syndrome and is associated with mutations in BRAF, MEK1, MEK2, and KRAS. The relationship between malignancy risk and CFCS is unclear with few cases published in the literature. The purpose of this paper is to describe the case of a patient with CFCS presenting in extremis as a result of a large intracerebral hemorrhage arising from a temporal bone mass with histopathology most consistent with chondroblastoma and secondary aneurysmal bone cyst. This is the first case to document an association between CFCS and chondroblastoma.

Multifocal Pigmented Villonodular Synovitis in the Noonan Syndrome

Noonan-like/multiple giant cell lesion (NS/MGCL) is a rare condition overlapping with Noonan syndrome. Once thought to be a specific and separate entity, it is now suggested to be a variant of the Noonan syndrome spectrum. We report the case of an 8-year-old boy with a typical clinical picture of Noonan syndrome with a de novo germline mutation of PTPN11 (c.854 T>C). During his follow-up, the patient developed multifocal pigmented villonodular synovitis which first affected the left knee and shortly after both elbows.

The novel RAF1 mutation p.(Gly361Ala) located outside the kinase domain of the CR3 region in two patients with Noonan syndrome, including one with a rare brain tumor

Noonan syndrome is characterized by typical craniofacial dysmorphism, postnatal growth retardation, congenital heart defect, and learning difficulties and belongs to the RASopathies, a group of neurodevelopmental disorders caused by germline mutations in genes encoding components of the RAS-MAPK pathway. Mutations in the RAF1 gene are associated with Noonan syndrome, with a high prevalence of hypertrophic cardiomyopathy (HCM). RAF1 mutations cluster in exons encoding the conserved region 2 (CR2), the kinase activation segment of the CR3 domain, and the C-terminus. We present two boys with Noonan syndrome and the identical de novo RAF1 missense variant c.1082G>C/p.(Gly361Ala) affecting the CR3, but located outside the kinase activation segment. The p.(Gly361Ala) mutation has been identified as a RAF1 allele conferring resistance to RAF inhibitors. This amino acid change favors a RAF1 conformation that allows for enhanced RAF dimerization and increased intrinsic kinase activity. Both patients with Noonan syndrome showed typical craniofacial dysmorphism, macrocephaly, and short stature. One individual developed HCM and was diagnosed with a disseminated oligodendroglial-like leptomeningeal tumor (DOLT) of childhood at the age of 9 years. While there is a well-established association of NS with malignant tumors, especially childhood hemato-oncological diseases, brain tumors have rarely been reported in Noonan syndrome. Our data demonstrate that mutation scanning of the entire coding region of genes associated with Noonan syndrome is mandatory not to miss rare variants located outside the known mutational hotspots.

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.

Multifocal tenosynovial giant cell tumors in a child with Noonan syndrome

Noonan syndrome is a genetic disorder with variable expression of distinctive facial features, webbed neck, chest deformity, short stature, cryptorchidism and congenital heart disease. The association of Noonan syndrome and giant cell granulomas of the mandible is widely reported. However, Noonan syndrome may also be associated with single or multifocal tenosynovial giant cell tumors, also referred to as pigmented villonodular synovitis. We report a child with Noonan syndrome, giant cell granulomas of the mandible and synovial and tenosynovial giant cell tumors involving multiple joints and tendon sheaths who was initially misdiagnosed with juvenile idiopathic arthritis. It is important for radiologists to be aware of the association of Noonan syndrome and multifocal giant cell lesions, which can range from the more commonly described giant cell granulomas of the mandible to isolated or multifocal intra- or extra-articular tenosynovial giant cell tumors or a combination of all of these lesions.