Noonan Syndrome


Noonan Syndrome is an autosamal dominant multi-system disorder, characterised by facial anomalies, short stature, developmental delay, cardiac abnormalities and other symptoms. The syndrome pre-disposes to myeloproliferative disorders ( mainly chronic myeolomonocytic leukemia / juvenile myelomonocytic leukemia and acute lymphoblastic leukemia), with reports of neuroblastoma, rhabdomyosarcoma and a wide range of other tumors.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • SOS1 Protein
  • NF1
  • Autologous Transplantat
  • Neurofibromin 1
  • Missense Mutation
  • Proto-Oncogene Proteins
  • Germ-Line Mutation
  • DNA Mutational Analysis
  • Amino Acid Substitution
  • p120 GTPase Activating Protein
  • Infant
  • MAP Kinase Signaling System
  • Mutation
  • NRAS
  • Protein Tyrosine Phosphatases
  • Phenotype
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • LEOPARD Syndrome
  • Intracellular Signaling Peptides and Proteins
  • Congenital Heart Defects
  • DNA Sequence Analysis
  • PTPN11
  • Neurofibromatosis 1
  • Pedigree
  • Leukemia, Myelomonocytic, Juvenile
  • Neurofibromatosis
  • Pulmonary Valve Stenosis
  • Adolescents
  • Synovitis, Pigmented Villonodular
  • ras Proteins
  • Newborns
  • Differential Diagnosis
  • Genotype
  • CRAF
  • Genetic Predisposition
  • Childhood Cancer
  • Noonan Syndrome
  • Signal Transduction
  • Exons
  • Costello Syndrome
  • Acute Lymphocytic Leukaemia
  • KRAS
Tag cloud generated 29 August, 2019 using data from PubMed, MeSH and CancerIndex

Mutated Genes and Abnormal Protein Expression (6)

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PTPN11 12q24.13 CFC, NS1, JMML, SHP2, BPTP3, PTP2C, METCDS, PTP-1D, SH-PTP2, SH-PTP3 -PTPN11 and Noonan Syndrome
KRAS 12p12.1 NS, NS3, CFC2, RALD, KRAS1, KRAS2, RASK2, KI-RAS, C-K-RAS, K-RAS2A, K-RAS2B, K-RAS4A, K-RAS4B, c-Ki-ras2 -KRAS mutation in Noonan Syndrome
SOS1 2p21 GF1, HGF, NS4, GGF1, GINGF -SOS1 mutation in Noonan Syndrome
RAF1 3p25.2 NS5, CRAF, Raf-1, c-Raf, CMD1NN -RAF1 mutation in Noonan Syndrome
NRAS 1p13.2 NS6, CMNS, NCMS, ALPS4, N-ras, NRAS1 -NRAS mutation Noonan Syndrome
CBL 11q23.3 CBL2, NSLL, C-CBL, RNF55, FRA11B -CBL mutation in Noonan Syndrome

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications

Noonan Syndrome and cancer:
Tatiana S, Marta J, Monika M, Pavel V
Noonan syndrome from a fetopathologist perspective.
Cesk Patol. 2019; 55(1):48-52 [PubMed] Related Publications
We present our experience with four cases of fetal autopsies with abnormal prenatal ultrasound findings and suspicion of Noonan syndrome. These were fetuses from the 17th to the 24th age of gestation (GA). In all cases, prenatal ultrasound examination recorded increased nuchal translucency (NT) and presence of lymphatic neck sacs. Some fetuses showed signs of fetal hydrops and polyhydramnion was found. Similar signs and congenital developmental defects were confirmed in the autopsy examination. These were primarily signs of developing fetal hydrops with increased nuchal edema, in some cases up to the character of cystic hygroma, pleural and abdominal effusions, congenital heart and kidney defects, skeletal defects and facial dysmorphism. A karyotype was examined in all cases without chromosome aneuploidy. The diagnosis of NS was confimed by subsequent genetic analysis of causal gene mutations (mainly PTPN11, KRAS, RAF 1,). Our cases demonstrate a wide range of signs of prenatal presentation of this syndrome. Because of wide differential diagnosis, summarizing prenatal ultrasound findings, autopsy examination and molecular genetic testing is essential.

Schreurs L, Lannoo L, De Catte L, et al.
First trimester cystic hygroma colli: Retrospective analysis in a tertiary center.
Eur J Obstet Gynecol Reprod Biol. 2018; 231:60-64 [PubMed] Related Publications
OBJECTIVE: This retrospective study aims to evaluate the incidence, presence of chromosomal anomalies and outcome of fetuses diagnosed with cystic hygroma colli in the first trimester in a single tertiary center.
STUDY DESIGN: A retrospective study was performed over a ten-years period from 2007 to 2017 of all fetuses with a first-trimester diagnosis of cystic hygroma. Maternal and fetal parameters were assessed with descriptive statistics.
RESULTS: A total of 185 singleton pregnancies were included. Chromosomal anomalies were present in 122 cases (65.9%). Sixty-three fetuses (34.1%) had a normal karyotype. Noonan syndrome was diagnosed in 6 cases using additional testing for RASopathies. In euploid fetuses, a major congenital anomaly was detected in 35 of 63 cases (56%) and if present, 91.4% had an abnormal fetal outcome compared to 32.1% if no structural anomaly was found (p < 0.01). Fetuses with a nuchal translucency thickness more than 10 mm and hydropic fetuses had a worse outcome.
DISCUSSION: Associated structural anomalies or hydrops fetalis are significant predictors for an abnormal outcome in pregnancies with first-trimester cystic hygroma and a normal karyotype. Cytogenetic evaluation and detailed sonographic evaluation are of great importance in the determination of the prognosis of pregnancies complicated by first-trimester cystic hygroma.

Prasad RM, Mody RJ, Myers G, et al.
A genome-wide analysis of colorectal cancer in a child with Noonan syndrome.
Pediatr Blood Cancer. 2018; 65(11):e27362 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Noonan syndrome (NS) is a developmental syndrome caused by germline mutations in the Ras signaling pathway. No association has been shown between NS and pediatric colorectal cancer (CRC). We report the case of CRC in a pediatric patient with NS. The patient underwent whole genome sequencing. A germline SOS1 mutation c.1310T>C (p. Ile437Thr) confirmed NS diagnosis. No known hereditary cancer syndromes were identified. Tumor analysis revealed two mutations: a TP53 missense mutation c.481G>A (p. Ala161Tyr) and NCOR1 nonsense mutation c.6052C>T (p. Arg2018*). This report highlights the complexity of Ras signaling and the interplay between developmental syndromes and cancer.

Bizaoui V, Gage J, Brar R, et al.
RASopathies are associated with a distinct personality profile.
Am J Med Genet B Neuropsychiatr Genet. 2018; 177(4):434-446 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Personality is a complex, yet partially heritable, trait. Although some Mendelian diseases like Williams-Beuren syndrome are associated with a particular personality profile, studies have failed to assign the personality features to a single gene or pathway. As a family of monogenic disorders caused by mutations in the Ras/MAPK pathway known to influence social behavior, RASopathies are likely to provide insight into the genetic basis of personality. Eighty subjects diagnosed with cardiofaciocutaneous syndrome, Costello syndrome, neurofibromatosis type 1, and Noonan syndrome were assessed using a parent-report BFQ-C (Big Five Questionnaire for Children) evaluating agreeableness, extraversion, conscientiousness, intellect/openness, and neuroticism, along with 55 unaffected sibling controls. A short questionnaire was added to assess sense of humor. RASopathy subjects and sibling controls were compared for individual components of personality, multidimensional personality profiles, and individual questions using Student tests, analysis of variance, and principal component analysis. RASopathy subjects were given lower scores on average compared to sibling controls in agreeableness, extraversion, conscientiousness, openness, and sense of humor, and similar scores in neuroticism. When comparing the multidimensional personality profile between groups, RASopathies showed a distinct profile from unaffected siblings, but no difference in this global profile was found within RASopathies, revealing a common profile for the Ras/MAPK-related disorders. In addition, several syndrome-specific strengths or weaknesses were observed in individual domains. We describe for the first time an association between a single pathway and a specific personality profile, providing a better understanding of the genetics underlying personality, and new tools for tailoring educational and behavioral approaches for individuals with RASopathies.

Leung GKC, Luk HM, Tang VHM, et al.
Integrating Functional Analysis in the Next-Generation Sequencing Diagnostic Pipeline of RASopathies.
Sci Rep. 2018; 8(1):2421 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
RASopathies are a group of heterogeneous conditions caused by germline mutations in RAS/MAPK signalling pathway genes. With next-generation sequencing (NGS), sequencing capacity is no longer a limitation to molecular diagnosis. Instead, the rising number of variants of unknown significance (VUSs) poses challenges to clinical interpretation and genetic counselling. We investigated the potential of an integrated pipeline combining NGS and the functional assessment of variants for the diagnosis of RASopathies. We included 63 Chinese patients with RASopathies that had previously tested negative for PTPN11 and HRAS mutations. In these patients, we performed a genetic analysis of genes associated with RASopathies using a multigene NGS panel and Sanger sequencing. For the VUSs, we evaluated evidence from genetic, bioinformatic and functional data. Twenty disease-causing mutations were identified in the 63 patients, providing a primary diagnostic yield of 31.7%. Four VUSs were identified in five patients. The functional assessment supported the pathogenicity of the RAF1 and RIT1 VUSs, while the significance of two VUSs in A2ML1 remained unclear. In summary, functional analysis improved the diagnostic yield from 31.7% to 36.5%. Although technically demanding and time-consuming, a functional genetic diagnostic analysis can ease the clinical translation of these findings to aid bedside interpretation.

Harms FL, Alawi M, Amor DJ, et al.
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.
Am J Med Genet A. 2018; 176(2):470-476 [PubMed] Related Publications
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.

Lipka DB, Witte T, Toth R, et al.
RAS-pathway mutation patterns define epigenetic subclasses in juvenile myelomonocytic leukemia.
Nat Commun. 2017; 8(1):2126 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative disorder of early childhood characterized by mutations activating RAS signaling. Established clinical and genetic markers fail to fully recapitulate the clinical and biological heterogeneity of this disease. Here we report DNA methylome analysis and mutation profiling of 167 JMML samples. We identify three JMML subgroups with unique molecular and clinical characteristics. The high methylation group (HM) is characterized by somatic PTPN11 mutations and poor clinical outcome. The low methylation group is enriched for somatic NRAS and CBL mutations, as well as for Noonan patients, and has a good prognosis. The intermediate methylation group (IM) shows enrichment for monosomy 7 and somatic KRAS mutations. Hypermethylation is associated with repressed chromatin, genes regulated by RAS signaling, frequent co-occurrence of RAS pathway mutations and upregulation of DNMT1 and DNMT3B, suggesting a link between activation of the DNA methylation machinery and mutational patterns in JMML.

Yapijakis C, Pachis N, Voumvourakis C
Neurofibromatosis-Noonan Syndrome: A Possible Paradigm of the Combination of Genetic and Epigenetic Factors.
Adv Exp Med Biol. 2017; 987:151-159 [PubMed] Related Publications
Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia.

Castagna J, Clerc J, Dupond AS, Laresche C
[Multiple granular cell tumours in a patient with Noonan's syndrome and juvenile myelomonocytic leukaemia].
Ann Dermatol Venereol. 2017; 144(11):705-711 [PubMed] Related Publications
BACKGROUND: Granular cell tumour (GCT) is a rare form of tumour comprising Schwann cells. Herein, we report a case of a child presenting Noonan syndrome complicated by juvenile myelomonocytic leukaemia (JMML) and who also developed a multiple form of GCT. We discussed the molecular mechanisms that might account for this association.
PATIENTS AND METHODS: A six-year-old boy with Noonan syndrome complicated by JMML presented three asymptomatic subcutaneous nodules on his back, forearm and neck. Histological analysis revealed GCT. A literature review revealed seven cases of Noonan syndrome presenting GCT, none of which were associated with JMML. Mutation of gene PTPN11, via hyperactivation of intracellular Ras signalling may cause the development of GCT and JMML in children presenting Noonan syndrome.
DISCUSSION: Detailed clinical examination is recommended in children presenting GCT to screen for multiple forms and for signs of malformation suggestive of a genetic syndrome. Ours is the first case to be described of Noonan syndrome complicated by JMML associated with multiple GCT. This association once again raises the important question of the role of the Ras-MAPK signalling pathway in the development of benign and malignant tumours of solid organs or blood, associated with genetic syndromes.

Cao H, Alrejaye N, Klein OD, et al.
A review of craniofacial and dental findings of the RASopathies.
Orthod Craniofac Res. 2017; 20 Suppl 1:32-38 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
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.

Schmidbauer B, Menhart K, Hellwig D, Grosse J
Differentiated Thyroid Cancer-Treatment: State of the Art.
Int J Mol Sci. 2017; 18(6) [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Differentiated thyroid cancer (DTC) is a rare malignant disease, although its incidence has increased over the last few decades. It derives from follicular thyroid cells. Generally speaking, the prognosis is excellent. If treatment according to the current guidelines is given, cases of recurrence or persistence are rare. DTC requires special expertise by the treating physician. In recent years, new therapeutic options for these patients have become available. For this article we performed a systematic literature review with special focus on the guidelines of the American Thyroid Association, the European Association of Nuclear Medicine, and the German Society of Nuclear Medicine. For DTC, surgery and radioiodine therapy followed by levothyroxine substitution remain the established therapeutic procedures. Even metastasized tumors can be cured this way. However, in rare cases of radioiodine-refractory tumors, additional options are to be discussed. These include strict suppression of thyroid-stimulating hormone (also known as thyrotropin, TSH) and external local radiotherapy. Systemic cytostatic chemotherapy does not play a significant role. Recently, multikinase or tyrosine kinase inhibitors have been approved for the treatment of radioiodine-refractory DTC. Although a benefit for overall survival has not been shown yet, these new drugs can slow down tumor progression. However, they are frequently associated with severe side effects and should be reserved for patients with threatening symptoms only.

Villani A, Greer MC, Kalish JM, et al.
Recommendations for Cancer Surveillance in Individuals with RASopathies and Other Rare Genetic Conditions with Increased Cancer Risk.
Clin Cancer Res. 2017; 23(12):e83-e90 [PubMed] Related Publications
In October 2016, the American Association for Cancer Research held a meeting of international childhood cancer predisposition syndrome experts to evaluate the current knowledge of these syndromes and to propose consensus surveillance recommendations. Herein, we summarize clinical and genetic aspects of RASopathies and Sotos, Weaver, Rubinstein-Taybi, Schinzel-Giedion, and NKX2-1 syndromes as well as specific metabolic disorders known to be associated with increased childhood cancer risk. In addition, the expert panel reviewed whether sufficient data exist to make a recommendation that all patients with these disorders be offered cancer surveillance. For all syndromes, the panel recommends increased awareness and prompt assessment of clinical symptoms. Patients with Costello syndrome have the highest cancer risk, and cancer surveillance should be considered. Regular physical examinations and complete blood counts can be performed in infants with Noonan syndrome if specific

Duat-Rodriguez A, Hernandez-Martin A
[Update on the treatment of RASopathies].
Rev Neurol. 2017; 64(s03):S13-S17 [PubMed] Related Publications
INTRODUCTION: The term 'RASopathies' covers a series of diseases that present mutations in the genes that code for the proteins of the RAS/MAPK pathway. These diseases include neurofibromatosis type 1, Noonan syndrome, Legius syndrome, LEOPARD syndrome, Costello syndrome and cardiofaciocutaneous syndrome. Involvement of the RAS/MAPK pathway not only increases predisposition to develop tumours, but also determines the presence of phenotypic anomalies and alterations in learning processes.
AIM: To review the use of therapeutic strategies with mechanisms that have a selective action on RASopathies.
DEVELOPMENT: The fact that the RAS pathway is involved in a third of all neoplasms has led to the development and study of different drugs at this level. Some of these pharmaceutical agents have been tested in RASopathies, mainly in neurofibromatosis type 1. Here we analyse the use of different antitarget treatments: drugs that act on the membrane receptors, such as tyrosine kinase inhibitors, in the mTOR pathway or MEK inhibitors. These latter have shown potential benefits in recent studies conducted on different RASopathies.
CONCLUSIONS: Today, thanks to the results from the first studies conducted with MEK inhibitor based mainly on animal models, a number of promising clinical trials are being carried out.

Santoro C, Giugliano T, Melone MAB, et al.
Multiple spinal nerve enlargement and SOS1 mutation: Further evidence of overlap between neurofibromatosis type 1 and Noonan phenotype.
Clin Genet. 2018; 93(1):138-143 [PubMed] Related Publications
Neurofibromatosis type 1 (NF1) has long been considered a well-defined, recognizable monogenic disorder, with neurofibromas constituting a pathognomonic sign. This dogma has been challenged by recent descriptions of patients with enlarged nerves or paraspinal tumors, suggesting that neurogenic tumors and hypertrophic neuropathy may be a complication of Noonan syndrome with multiple lentigines (NSML) or RASopathy phenotype. We describe a 15-year-old boy, whose mother previously received clinical diagnosis of NF1 due to presence of bilateral cervical and lumbar spinal lesions resembling plexiform neurofibromas and features suggestive of NS. NF1 molecular analysis was negative in the mother. The boy presented with Noonan features, multiple lentigines and pectus excavatum. Next-generation sequencing analysis of all RASopathy genes identified p.Ser548Arg missense mutation in SOS1 in the boy, confirmed in his mother. Brain and spinal magnetic resonance imaging scans were negative in the boy. No heart involvement or deafness was observed in proband or mother. This is the first report of a SOS1 mutation associated with hypertrophic neuropathy resembling plexiform neurofibromas, a rare complication in Noonan phenotypes with mutations in RASopathy genes. Our results highlight the overlap between RASopathies, suggesting that NF1 diagnostic criteria need rethinking. Genetic analysis of RASopathy genes should be considered when diagnosis is uncertain.

Siegfried A, Cances C, Denuelle M, et al.
Noonan syndrome, PTPN11 mutations, and brain tumors. A clinical report and review of the literature.
Am J Med Genet A. 2017; 173(4):1061-1065 [PubMed] Related Publications
Noonan syndrome (NS), an autosomal dominant disorder, is characterized by short stature, congenital heart defects, developmental delay, and facial dysmorphism. PTPN11 mutations are the most common cause of NS. PTPN11 encodes a non-receptor protein tyrosine phosphatase, SHP2. Hematopoietic malignancies and solid tumors are associated with NS. Among solid tumors, brain tumors have been described in children and young adults but remain rather rare. We report a 16-year-old boy with PTPN11-related NS who, at the age of 12, was incidentally found to have a left temporal lobe brain tumor and a cystic lesion in the right thalamus. He developed epilepsy 2 years later. The temporal tumor was surgically resected because of increasing crises and worsening radiological signs. Microscopy showed nodules with specific glioneuronal elements or glial nodules, leading to the diagnosis of dysembryoplastic neuroepithelial tumor (DNT). Immunohistochemistry revealed positive nuclear staining with Olig2 and pERK in small cells. SHP2 plays a key role in RAS/MAPK pathway signaling which controls several developmental cell processes and oncogenesis. An amino-acid substitution in the N-terminal SHP2 domain disrupts the self-locking conformation and leads to ERK activation. Glioneuronal tumors including DNTs and pilocytic astrocytomas have been described in NS. This report provides further support for the relation of DNTs with RASopathies and for the implication of RAS/MAPK pathways in sporadic low-grade glial tumors including DNTs. © 2017 Wiley Periodicals, Inc.

Mason-Suares H, Toledo D, Gekas J, et al.
Juvenile myelomonocytic leukemia-associated variants are associated with neo-natal lethal Noonan syndrome.
Eur J Hum Genet. 2017; 25(4):509-511 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Gain-of-function variants in some RAS-MAPK pathway genes, including PTPN11 and NRAS, are associated with RASopathies and/or acquired hematological malignancies, most notably juvenile myelomonocytic leukemia (JMML). With rare exceptions, the spectrum of germline variants causing RASopathies does not overlap with the somatic variants identified in isolated JMML. Studies comparing these variants suggest a stronger gain-of-function activity in the JMML variants. As JMML variants have not been identified as germline defects and have a greater impact on protein function, it has been speculated that they would be embryonic lethal. Here we identified three variants, which have previously only been identified in isolated somatic JMML and other sporadic cancers, in four cases with a severe pre- or neo-natal lethal presentation of Noonan syndrome. These cases support the hypothesis that these stronger gain-of-function variants are rarely compatible with life.

O'Halloran K, Ritchey AK, Djokic M, Friehling E
Transient juvenile myelomonocytic leukemia in the setting of PTPN11 mutation and Noonan syndrome with secondary development of monosomy 7.
Pediatr Blood Cancer. 2017; 64(7) [PubMed] Related Publications
Juvenile myelomonocytic leukemia (JMML) is a rare childhood neoplasm with poor prognosis except in the setting of Noonan syndrome, where prognosis is generally favorable. We present the case of a child with JMML in the setting of germline PTPN11 mutation and Noonan syndrome with suspected secondary development of monosomy 7 in the bone marrow. Diagnosed shortly after birth, she has been managed with active surveillance alone. Myeloblast percentages initially fluctuated; however, bone marrow biopsy at 4 years of age showed spontaneous remission despite persistence of the monosomy 7 clone, supporting a cautious approach in similar cases.

Meyers AB, Awomolo AO, Szabo S
Multifocal tenosynovial giant cell tumors in a child with Noonan syndrome.
Pediatr Radiol. 2017; 47(3):361-365 [PubMed] Related Publications
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.

Dong L, Yu WM, Zheng H, et al.
Leukaemogenic effects of Ptpn11 activating mutations in the stem cell microenvironment.
Nature. 2016; 539(7628):304-308 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Germline activating mutations of the protein tyrosine phosphatase SHP2 (encoded by PTPN11), a positive regulator of the RAS signalling pathway, are found in 50% of patients with Noonan syndrome. These patients have an increased risk of developing leukaemia, especially juvenile myelomonocytic leukaemia (JMML), a childhood myeloproliferative neoplasm (MPN). Previous studies have demonstrated that mutations in Ptpn11 induce a JMML-like MPN through cell-autonomous mechanisms that are dependent on Shp2 catalytic activity. However, the effect of these mutations in the bone marrow microenvironment remains unclear. Here we report that Ptpn11 activating mutations in the mouse bone marrow microenvironment promote the development and progression of MPN through profound detrimental effects on haematopoietic stem cells (HSCs). Ptpn11 mutations in mesenchymal stem/progenitor cells and osteoprogenitors, but not in differentiated osteoblasts or endothelial cells, cause excessive production of the CC chemokine CCL3 (also known as MIP-1α), which recruits monocytes to the area in which HSCs also reside. Consequently, HSCs are hyperactivated by interleukin-1β and possibly other proinflammatory cytokines produced by monocytes, leading to exacerbated MPN and to donor-cell-derived MPN following stem cell transplantation. Remarkably, administration of CCL3 receptor antagonists effectively reverses MPN development induced by the Ptpn11-mutated bone marrow microenvironment. This study reveals the critical contribution of Ptpn11 mutations in the bone marrow microenvironment to leukaemogenesis and identifies CCL3 as a potential therapeutic target for controlling leukaemic progression in Noonan syndrome and for improving stem cell transplantation therapy in Noonan-syndrome-associated leukaemias.

Zhang J, Li M, Yao Z
Molecular screening strategies for NF1-like syndromes with café-au-lait macules (Review).
Mol Med Rep. 2016; 14(5):4023-4029 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Multiple café-au-lait macules (CALM) are usually associated with neurofibromatosis type 1 (NF1), one of the most common hereditary disorders. However, a group of genetic disorders presenting with CALM have mutations that are involved in human skin pigmentation regulation signaling pathways, including KIT ligand/KIT proto‑oncogene receptor tyrosine kinase and Ras/mitogen‑activated protein kinase. These disorders, which include Legius syndrome, Noonan syndrome with multiple lentigines or LEOPARD syndrome, and familial progressive hyperpigmentation) are difficult to distinguish from NF1 at early stages, using skin appearance alone. Furthermore, certain syndromes are clinically overlapping and molecular testing is a vital diagnostic method. The present review aims to provide an overview of these 'NF1‑like' inherited diseases and recommend a cost‑effective strategy for making a clear diagnosis among these diseases with an ambiguous borderline.

Salem B, Hofherr S, Turner J, et al.
Childhood Rhabdomyosarcoma in Association With a RASopathy Clinical Phenotype and Mosaic Germline SOS1 Duplication.
J Pediatr Hematol Oncol. 2016; 38(8):e278-e282 [PubMed] Related Publications
Childhood rhabdomyosarcoma (RMS) accounts for approximately 3.5% of cancer cases among children 0 to 14 years of age. Genetic conditions associated with high risk of childhood RMS include Li-Fraumeni syndrome, pleuropulmonary blastoma, Beckwith-Wiedemann syndrome, and some RASopathies, such as neurofibromatosis type 1, Costello syndrome (CS), and Noonan syndrome (NS). Here, we report the rare case of a 4-year-old girl with clinical features of NS who developed an embryonal RMS of the chest and needed emergent treatment. Molecular genetic testing identified a de novo, large, mosaic duplication of chromosome 2 encompassing the SOS1 gene, presumably caused by a mosaic, unbalanced translocation between chromosomes 2 and 17 found on routine cytogenetic analysis. Sequence analysis of all known genes causing Noonan spectrum disorders was negative. RMS has been reported in a few patients with NS, associated in very few with germline SOS1 mutations, but none with copy number abnormalities. This is the first report to our knowledge of early-onset RMS developing in a child with features of NS and a mosaic RAS pathway gene aberration, a large SOS1 duplication. We hypothesize that the inciting event for tumor development in this case is due to the germline mosaic duplication of SOS1, which was duplicated in all cells of the tumor, and the ultimate development of the tumor was further driven by multiple chromosomal aberrations in the tumor itself, all described as somatic events in isolated RMS tumors.

Mainberger F, Langer S, Mall V, Jung NH
Impaired synaptic plasticity in RASopathies: a mini-review.
J Neural Transm (Vienna). 2016; 123(10):1133-8 [PubMed] Related Publications
Synaptic plasticity in the form of long-term potentiation (LTP) and long-term depression (LTD) is considered to be the neurophysiological correlate of learning and memory. Impairments are discussed to be one of the underlying pathophysiological mechanisms of developmental disorders. In so-called RASopathies [e.g., neurofibromatosis 1 (NF1)], neurocognitive impairments are frequent and are affected by components of the RAS pathway which lead to impairments in synaptic plasticity. Transcranial magnetic stimulation (TMS) provides a non-invasive method to investigate synaptic plasticity in humans. Here, we review studies using TMS to evaluate synaptic plasticity in patients with RASopathies. Patients with NF1 and Noonan syndrome (NS) showed reduced cortical LTP-like synaptic plasticity. In contrast, increased LTP-like synaptic plasticity has been shown in Costello syndrome. Notably, lovastatin normalized impaired LTP-like plasticity and increased intracortical inhibition in patients with NF1. TMS has been shown to be a safe and efficient method to investigate synaptic plasticity and intracortical inhibition in patients with RASopathies. Deeper insights in impairments of synaptic plasticity in RASopathies could help to develop new options for the therapy of learning deficits in these patients.

Zhao B, Pritchard JR
Inherited Disease Genetics Improves the Identification of Cancer-Associated Genes.
PLoS Genet. 2016; 12(6):e1006081 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
The identification of biologically significant variants in cancer genomes is critical to therapeutic discovery, but it is limited by the statistical power needed to discern driver from passenger. Independent biological data can be used to filter cancer exomes and increase statistical power. Large genetic databases for inherited diseases are uniquely suited to this task because they contain specific amino acid alterations with known pathogenicity and molecular mechanisms. However, no rigorous method to overlay this information onto the cancer exome exists. Here, we present a computational methodology that overlays any variant database onto the somatic mutations in all cancer exomes. We validate the computation experimentally and identify novel associations in a re-analysis of 7362 cancer exomes. This analysis identified activating SOS1 mutations associated with Noonan syndrome as significantly altered in melanoma and the first kinase-activating mutations in ACVR1 associated with adult tumors. Beyond a filter, significant variants found in both rare cancers and rare inherited diseases increase the unmet medical need for therapeutics that target these variants and may bootstrap drug discovery efforts in orphan indications.

Fang Z, Marshall CB, Yin JC, et al.
Biochemical Classification of Disease-associated Mutants of RAS-like Protein Expressed in Many Tissues (RIT1).
J Biol Chem. 2016; 291(30):15641-52 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
RAS-like protein expressed in many tissues 1 (RIT1) is a disease-associated RAS subfamily small guanosine triphosphatase (GTPase). Recent studies revealed that germ-line and somatic RIT1 mutations can cause Noonan syndrome (NS), and drive proliferation of lung adenocarcinomas, respectively, akin to RAS mutations in these diseases. However, the locations of these RIT1 mutations differ significantly from those found in RAS, and do not affect the three mutational "hot spots" of RAS. Moreover, few studies have characterized the GTPase cycle of RIT1 and its disease-associated mutants. Here we developed a real-time NMR-based GTPase assay for RIT1 and investigated the effect of disease-associated mutations on GTPase cycle. RIT1 exhibits an intrinsic GTP hydrolysis rate similar to that of H-RAS, but its intrinsic nucleotide exchange rate is ∼4-fold faster, likely as a result of divergent residues near the nucleotide binding site. All of the disease-associated mutations investigated increased the GTP-loaded, activated state of RIT1 in vitro, but they could be classified into two groups with different intrinsic GTPase properties. The S35T, A57G, and Y89H mutants exhibited more rapid nucleotide exchange, whereas F82V and T83P impaired GTP hydrolysis. A RAS-binding domain pulldown assay indicated that RIT1 A57G and Y89H were highly activated in HEK293T cells, whereas T83P and F82V exhibited more modest activation. All five mutations are associated with NS, whereas two (A57G and F82V) have also been identified in urinary tract cancers and myeloid malignancies. Characterization of the effects on the GTPase cycle of RIT1 disease-associated mutations should enable better understanding of their role in disease processes.

Gezdirici A, Ekiz A, Güleç EY, et al.
How necessary is to analyze PTPN11 gene in fetuses with first trimester cystic hygroma and normal karyotype?
J Matern Fetal Neonatal Med. 2017; 30(8):938-941 [PubMed] Related Publications
Cystic hygroma (CH) is a vascular-lymphatic malformation and can occur either as an isolated finding or as a part of a syndrome. The incidence of CH is about 1:1000-1:6000 births. Ultrasonographic diagnosis of CH is usually obtained in the first trimester, and the lesion can appear in septated or non-septated forms. Increased nuchal translucency and CH have been associated with a wide range of structural and genetic abnormalities. Most of CHs are associated with a number of chromosomal abnormalities especially Trisomy 21, 13, 18 and Turner syndrome. Besides, the associations between CH and non-chromosomal syndromes were also reported and Noonan Syndrome (NS) is one of the leading causes. Approximately 50% of NS cases are caused by mutations in the PTPN11 gene. A novel PTPN11 mutation defined in two separate fetuses with CH and associated with NS phenotype is being reported here.

Hernández-Porras I, Schuhmacher AJ, Garcia-Medina R, et al.
K-Ras(V14I) -induced Noonan syndrome predisposes to tumour development in mice.
J Pathol. 2016; 239(2):206-17 [PubMed] Related Publications
The Noonan syndrome (NS) is an autosomal dominant genetic disorder characterized by short stature, craniofacial dysmorphism, and congenital heart defects. A significant proportion of NS patients may also develop myeloproliferative disorders (MPDs), including juvenile myelomonocytic leukaemia (JMML). Surprisingly, scarce information is available in relation to other tumour types in these patients. We have previously developed and characterized a knock-in mouse model that carries one of the most frequent KRAS-NS-related mutations, the K-Ras(V14I) substitution, which recapitulates most of the alterations described in NS patients, including MPDs. The K-Ras(V14I) mutation is a mild activating K-Ras protein; thus, we have used this model to study tumour susceptibility in comparison with mice expressing the classical K-Ras(G12V) oncogene. Interestingly, our studies have shown that these mice display a generalized tumour predisposition and not just MPDs. In fact, we have observed that the K-Ras(V14I) mutation is capable of cooperating with the p16Ink4a/p19Arf and Trp53 tumour suppressors, as well as with other risk factors such as pancreatitis, thereby leading to a higher cancer incidence. In conclusion, our results illustrate that the K-Ras(V14I) activating protein is able to induce cancer, although at a much lower level than the classical K-Ras(G12V) oncogene, and that it can be significantly modulated by both genetic and non-genetic events. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Yapijakis C, Pachis N, Natsis S, Voumvourakis C
Is Neurofibromatosis Type 1-Noonan Syndrome a Phenotypic Result of Combined Genetic and Epigenetic Factors?
In Vivo. 2016 May-Jun; 30(3):315-20 [PubMed] Related Publications
BACKGROUND/AIM: Neurofibromatosis 1-Noonan syndrome (NFNS) presents combined characteristics of both autosomal dominant disorders: NF1 and Noonan syndrome (NS). The genes causing NF1 and NS are located on different chromosomes, making it uncertain whether NFNS is a separate entity as previously suggested, or rather a clinical variation.
PATIENTS AND METHODS: We present a four-membered Greek family. The father was diagnosed with familial NF1 and the mother with generalized epilepsy, being under hydantoin treatment since the age of 18 years. Their two male children exhibited NFNS characteristics.
RESULTS: The father and his sons shared R1947X mutation in the NF1 gene. The two children with NFNS phenotype presented with NF1 signs inherited from their father and fetal hydantoin syndrome-like phenotype due to exposure to that anticonvulsant during fetal development.
CONCLUSION: The NFNS phenotype may be the result of both a genetic factor (mutation in the NF1 gene) and an epigenetic/environmental factor (e.g. hydantoin).

[The Biological Function of SHP2 in Human Disease].
Mol Biol (Mosk). 2016 Jan-Feb; 50(1):27-33 [PubMed] Related Publications
Tyrosyl phosphorylation participates in various pathological and physiological processes, which are regulated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). The Src homology-2 domain containing phosphatase SHP2 (encoded by PTPN11) is an important phosphatase, which was found to be implicated in the regulation of genetic disease, development, metabolic, neurological, muscle, skeletal disease and cancer. Germline mutations in PTPN11 cause the Noonan Syndrome, LEOPARD syndrome and metachondromatosis. Somatic PTPN11 mutations occur in hematologic malignancies and in solid tumors. SHP2 is also an important component in oncogenic signaling pathways. It may play different roles in different stages and positions of human cancers. Whether SHP2 is an oncogene or cancer suppressor gene remains to be elucidated. Elucidation of the regulatory mechanisms of SHP2 in human disease will provide new insights into disease and new targets for therapy. Here, we summarized the structural basis and recent research progression on SHP2 in various human disease, including genetic and cancer diseases.

Cavé H, Caye A, Strullu M, et al.
Acute lymphoblastic leukemia in the context of RASopathies.
Eur J Med Genet. 2016; 59(3):173-8 [PubMed] Related Publications
Noonan syndrome is associated with a range of malignancies including acute lymphoblastic leukemia (ALL). However, little information is available regarding the frequency, natural history, characteristics and prognosis of ALL in Noonan syndrome or RASopathies in general. Cross-referencing data from a large prospective cohort of 1176 patients having a molecularly confirmed RASopathy with data from the French childhood cancer registry allowed us to identify ALL in 6 (0.5%) patients including 4/778 (0.5%) with a germline PTPN11 mutation and 2/94 (2.1%) with a germline SOS1 mutation. None of the patients of our series with CFC syndrome (with germline BRAF or MAP2K1/MAP2K2 mutation - n = 121) or Costello syndrome (with HRAS mutation - n = 35) had an ALL. A total of 19 Noonan-ALL were gathered by adding our patients to those of the International Berlin-Munster-Frankfurt (I-BFM) study group and previously reported patients. Strikingly, all Noonan-associated ALL were B-cell precursor ALL, and high hyperdiploidy with more than 50 chromosomes was found in the leukemia cells of 13/17 (76%) patients with available genetics data. Our data suggest that children with Noonan syndrome are at higher risk to develop ALL. Like what is observed for somatic PTPN11 mutations, NS is preferentially associated with the development of hyperdiploid ALL that will usually respond well to chemotherapy. However, Noonan syndrome patients seem to have a propensity to develop post therapy myelodysplasia that can eventually be fatal. Hence, one should be particularly cautious when treating these patients.

Vurallı D, Gönç N, Vidaud D, et al.
Growth Hormone Deficiency in a Child with Neurofibromatosis-Noonan Syndrome.
J Clin Res Pediatr Endocrinol. 2016; 8(1):96-100 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Neurofibromatosis-Noonan syndrome (NFNS) is a distinct entity which shows the features of both NF1 (neurofibromatosis 1) and Noonan syndrome (NS). While growth hormone deficiency (GHD) has been relatively frequently identified in NF1 and NS patients, there is limited experience in NFNS cases. The literature includes only one case report of a NFNS patient having GHD and that report primarily focuses on the dermatological lesions that accompany the syndrome and not on growth hormone (GH) treatment. Here, we present a 13-year-old girl who had clinical features of NFNS with a mutation in the NF1 gene. The case is the first NFNS patient reported in the literature who was diagnosed to have GHD and who received GH treatment until reaching final height. The findings in this patient show that short stature is a feature of NFNS and can be caused by GHD. Patients with NFNS who show poor growth should be evaluated for GHD.

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