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Palit A, Inamadar AC. RASopathies: Dermatologists’ viewpoints. Indian J Dermatol Venereol Leprol 2021; 88:452-463. [DOI: 10.25259/ijdvl_799_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 04/01/2021] [Indexed: 11/04/2022]
Abstract
Ras/mitogen-activated protein kinase pathway dysregulation results in a group of disorders, collectively termed as RASopathies. Neurofibromatosis type 1, Noonan syndrome, Noonan syndrome with multiple lentigines, Noonan syndrome/loose anagen hair, Legius syndrome, Costello syndrome, cardio-facio-cutaneous syndrome and capillary malformation-arteriovenous malformation are the well-recognized RASopathies. These are characterized by multi-organ tumours and hamartomas. Some other features in common are facial dysmorphism, skeletal abnormalities, congenital heart disease, neurocognitive abnormalities and risk of various solid-organ and haematological malignancies. Some of the RASopathies are heterogeneous, caused by several gene mutations resulting in variations in phenotypes and severity ranging from mild to fatal. Significant phenotypic overlaps among different disorders, often makes it difficult to pinpoint a clinical diagnosis. Specific cutaneous manifestations are present in some of the RASopathies and are often the earliest clinical signs/symptoms. Hence, dermatologists contribute significantly as primary care physicians by identifying disorder-specific cutaneous lesions. However, diagnostic work-up and management of these disorders are often multidisciplinary. Confirmation of diagnosis is possible only by genetic mapping in each case. Genetic counseling of the patients and the affected families is an important component of the management. The aim of this review is description of cutaneous manifestations of RASopathies in the background of multi-system involvement to enable dermatologists a comprehensive and logical approach to work up and diagnose such patients in the absence of facility for specific molecular testing.
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Affiliation(s)
| | - Arun C. Inamadar
- Department of Dermatology, Venereology and Leprosy, Shri B. M. Patil Medical College, Hospital and Research Center, BLDE University, Vijayapur, Karnataka, India
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Fowlkes JL, Thrailkill KM, Bunn RC. RASopathies: The musculoskeletal consequences and their etiology and pathogenesis. Bone 2021; 152:116060. [PMID: 34144233 PMCID: PMC8316423 DOI: 10.1016/j.bone.2021.116060] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 01/07/2023]
Abstract
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.
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Affiliation(s)
- John L Fowlkes
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America.
| | - Kathryn M Thrailkill
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
| | - R Clay Bunn
- University of Kentucky Barnstable Brown Diabetes Center, Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, United States of America
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Borrie SC, Plasschaert E, Callaerts-Vegh Z, Yoshimura A, D'Hooge R, Elgersma Y, Kushner SA, Legius E, Brems H. MEK inhibition ameliorates social behavior phenotypes in a Spred1 knockout mouse model for RASopathy disorders. Mol Autism 2021; 12:53. [PMID: 34311771 PMCID: PMC8314535 DOI: 10.1186/s13229-021-00458-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 07/12/2021] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND RASopathies are a group of disorders that result from mutations in genes coding for proteins involved in regulating the Ras-MAPK signaling pathway, and have an increased incidence of autism spectrum disorder (ASD). Legius syndrome is a rare RASopathy caused by loss-of-function mutations in the SPRED1 gene. The patient phenotype is similar to, but milder than, Neurofibromatosis type 1-another RASopathy caused by loss-of-function mutations in the NF1 gene. RASopathies exhibit increased activation of Ras-MAPK signaling and commonly manifest with cognitive impairments and ASD. Here, we investigated if a Spred1-/- mouse model for Legius syndrome recapitulates ASD-like symptoms, and whether targeting the Ras-MAPK pathway has therapeutic potential in this RASopathy mouse model. METHODS We investigated social and communicative behaviors in Spred1-/- mice and probed therapeutic mechanisms underlying the observed behavioral phenotypes by pharmacological targeting of the Ras-MAPK pathway with the MEK inhibitor PD325901. RESULTS Spred1-/- mice have robust increases in social dominance in the automated tube test and reduced adult ultrasonic vocalizations during social communication. Neonatal ultrasonic vocalization was also altered, with significant differences in spectral properties. Spred1-/- mice also exhibit impaired nesting behavior. Acute MEK inhibitor treatment in adulthood with PD325901 reversed the enhanced social dominance in Spred1-/- mice to normal levels, and improved nesting behavior in adult Spred1-/- mice. LIMITATIONS This study used an acute treatment protocol to administer the drug. It is not known what the effects of longer-term treatment would be on behavior. Further studies titrating the lowest dose of this drug that is required to alter Spred1-/- social behavior are still required. Finally, our findings are in a homozygous mouse model, whereas patients carry heterozygous mutations. These factors should be considered before any translational conclusions are drawn. CONCLUSIONS These results demonstrate for the first time that social behavior phenotypes in a mouse model for RASopathies (Spred1-/-) can be acutely reversed. This highlights a key role for Ras-MAPK dysregulation in mediating social behavior phenotypes in mouse models for ASD, suggesting that proper regulation of Ras-MAPK signaling is important for social behavior.
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Affiliation(s)
- Sarah C Borrie
- Department of Human Genetics, KU Leuven, O&N1 Herestraat 49, Box 607, 3000, Leuven, Belgium
| | - Ellen Plasschaert
- Department of Human Genetics, KU Leuven, O&N1 Herestraat 49, Box 607, 3000, Leuven, Belgium
| | | | - Akihiko Yoshimura
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Rudi D'Hooge
- Laboratory for Biological Psychology, KU Leuven, Leuven, Belgium
| | - Ype Elgersma
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Neuroscience, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Steven A Kushner
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Eric Legius
- Department of Human Genetics, KU Leuven, O&N1 Herestraat 49, Box 607, 3000, Leuven, Belgium
| | - Hilde Brems
- Department of Human Genetics, KU Leuven, O&N1 Herestraat 49, Box 607, 3000, Leuven, Belgium.
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Borrie SC, Horner AE, Yoshimura A, Legius E, Kopanitsa MV, Brems H. Impaired instrumental learning in Spred1 -/- mice, a model for a rare RASopathy. GENES BRAIN AND BEHAVIOR 2021; 20:e12727. [PMID: 33624414 DOI: 10.1111/gbb.12727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 01/27/2021] [Accepted: 02/22/2021] [Indexed: 12/31/2022]
Abstract
RASopathies are neuro-cardio-facio-cutaneous disorders stemming from mutations in genes regulating the RAS-MAPK pathway. Legius syndrome is a rare RASopathy disorder caused by mutations in the SPRED1 gene. SPRED1 protein negatively regulates activation of Ras by inhibiting RAS/RAF and by its interaction with neurofibromin, a Ras GTPase-activating protein (RAS-GAP). Cognitive impairments have been reported in Legius syndrome as well as in other RASopathy disorders. Modelling these cognitive deficits in a Spred1 mouse model for Legius syndrome has demonstrated spatial learning and memory deficits, but other cognitive domains remained unexplored. Here, we attempted to utilize a cognitive touchscreen battery to investigate if Spred1-/- mice exhibit deficits in other cognitive domains. We show that Spred1-/- mice had heterogeneous performance in instrumental operant learning, with a large subgroup (n = 9/20) failing to reach the standard criterion on touchscreen operant pretraining, precluding further cognitive testing. To examine whether targeting the RAS-MAPK signalling pathway could rescue these cognitive impairments, Spred1-/- mice were acutely treated with the clinically relevant mitogen-activated protein kinase (MEK) inhibitor PD325901. However, MEK inhibition did not improve their instrumental learning. We conclude that Spred1-/- mice can model severe cognitive impairments that cannot be reversed in adulthood.
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Affiliation(s)
- Sarah C Borrie
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Akihiko Yoshimura
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Eric Legius
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Hilde Brems
- Department of Human Genetics, KU Leuven, Leuven, Belgium
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Orlandi V, Cavarzere P, Palma L, Gaudino R, Antoniazzi F. Central precocious puberty in a girl with LEGIUS syndrome: an accidental association? Ital J Pediatr 2021; 47:50. [PMID: 33663580 PMCID: PMC7934465 DOI: 10.1186/s13052-021-01004-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Central precocious puberty is a condition characterized by precocious activation of the hypothalamic-pituitary-gonadal axis. It may be idiopathic or secondary to organic causes, including syndromes such as Neurofibromatosis type 1 (NF1). CASE PRESENTATION We presented a girl of 6 years and 10 months with almost 11 café-au-lait skin macules, without other clinical or radiological signs typical of NF1, and with a central precocious puberty. Genetic analysis evidenced the new variant NM-152594.2:c.304delAp. (Thr102Argfs*19) in SPRED1 gene, which allowed to diagnose Legius syndrome. CONCLUSIONS We report for the first time a case of central precocious puberty in a girl with Legius syndrome. The presence of central precocious puberty in a child with characteristic café-au-lait macules should suggest pediatricians to perform genetic analysis in order to reach a definitive diagnosis. Further studies on timing of puberty in patients with RASopathies are needed to better elucidate if this clinical association is casual or secondary to their clinical condition.
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Affiliation(s)
- Valentina Orlandi
- Pediatric Division, Department of Pediatrics, University Hospital of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - Paolo Cavarzere
- Pediatric Division, Department of Pediatrics, University Hospital of Verona, Piazzale Stefani 1, 37126, Verona, Italy.
| | - Laura Palma
- Pediatric Division, Department of Pediatrics, University Hospital of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - Rossella Gaudino
- Pediatric Division, Department of Pediatrics, University Hospital of Verona, Piazzale Stefani 1, 37126, Verona, Italy.,Pediatric Clinic, Department Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy
| | - Franco Antoniazzi
- Pediatric Division, Department of Pediatrics, University Hospital of Verona, Piazzale Stefani 1, 37126, Verona, Italy.,Pediatric Clinic, Department Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy.,Regional Center for the diagnosis and treatment of children and adolescents rare skeletal disorders. Pediatric Clinic, Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy
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Walsh KS, del Castillo A, Kennedy T, Karim AI, Semerjian C. A Review of Psychological, Social, and Behavioral Functions in the RASopathies. JOURNAL OF PEDIATRIC NEUROPSYCHOLOGY 2020. [DOI: 10.1007/s40817-020-00088-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Pierpont EI, Wolford M. Behavioral functioning in cardiofaciocutaneous syndrome: Risk factors and impact on parenting experience. Am J Med Genet A 2016; 170:1974-88. [PMID: 27149079 DOI: 10.1002/ajmg.a.37725] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/24/2016] [Indexed: 11/10/2022]
Abstract
The present study is an investigation of behavioral functioning in children with cardiofaciocutaneous syndrome (CFC). CFC is a rare single-gene disorder associated with cardiac disease, characteristic skin and facial features, intellectual disability, and neurological complications such as seizures and structural brain anomalies. Emotional and behavioral features of CFC have not been systematically investigated. We aimed to identify key variables that contribute to psychopathology during childhood and adolescence, and to examine the impact of challenging behaviors on the caregiving experience. Parents of 34 children and adolescents with CFC completed standardized broadband measures of child emotional and behavioral functioning, as well as measures of sensory modulation, functional communication, and caregiver stress. Results indicate that children with CFC syndrome are at heightened risk for psychopathology, with attention problems, social difficulties, and unusual behaviors (e.g., obsessive thoughts, strange behaviors, repetitive acts) found to be especially prevalent. Behavioral challenges in children with CFC syndrome were significantly associated with a history of obstetric complications and with problems modulating sensory information. With regard to the impact of child neurocognitive and behavioral issues on the caregiving experience, parent self-reported stress was significantly higher among parents of children who engaged in more problem behaviors, and lower among parents whose children could communicate effectively with others. Results of this study suggest avenues to help families cope with CFC-related stressors and enhance overall functioning. In particular, this study highlights the need for educational and treatment interventions aimed at addressing sensory needs, increasing functional communication, and identifying and managing challenging behaviors. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Elizabeth I Pierpont
- Division of Clinical Behavioral Neuroscience, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Melinda Wolford
- Department of Counseling, Special Education and School Psychology, Youngstown State University, Youngstown, Ohio
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Benelli E, Bruno I, Belcaro C, Ventura A, Berti I. Legius syndrome: case report and review of literature. Ital J Pediatr 2015; 41:8. [PMID: 25883013 PMCID: PMC4323213 DOI: 10.1186/s13052-015-0115-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/26/2015] [Indexed: 11/10/2022] Open
Abstract
A 8-month-old child was referred to our Dermatologic Unit for suspected Neurofibromatosis type 1 (NF 1), because of the appearance, since few days after birth, of numerous café-au-lait spots (seven larger than 5 mm); no other sign evocative of NF 1 was found. Her family history was remarkable for the presence of multiple café-au-lait spots in the mother, the grandfather and two aunts. The family had been already examined for NF 1, but no sign evocative of the disease was found. We then suspected Legius syndrome, a dominant disease characterized by a mild neurofibromatosis 1 phenotype. The diagnosis was confirmed by the finding of a mutation in SPRED1 gene, a feedback regulator of RAS/MAPK signaling. Here, we discuss the differential diagnosis of cafè-au-lait spots and we briefly review the existing literature about Legius syndrome.
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Affiliation(s)
| | - Irene Bruno
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy.
| | | | - Alessandro Ventura
- University of Trieste, Trieste, Italy. .,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy.
| | - Irene Berti
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy.
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Finsterer J, Stollberger C, Stubenberger E, Tschakoschian S. Lymphangiopathy in neurofibromatosis 1 manifesting with chylothorax, pericardial effusion, and leg edema. Int J Gen Med 2013; 6:743-6. [PMID: 24043952 PMCID: PMC3772692 DOI: 10.2147/ijgm.s45825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background This case report documents the affliction of the lymph vessels as a phenotypic feature of neurofibromatosis-1 (NF-1). Methodology Routine transthoracic echocardiography, computed tomography scan of the thorax, magnetic resonance angiography of the renal arteries, and conventional digital subtraction angiography were applied. Comprehensive NF-1 mutation analysis was carried out by fluorescence in situ hybridization analysis, long-range reverse transcriptase polymerase chain reaction, and multiple-ligation probe assay. All other investigations were performed using routine, well-established techniques. Results The subject is a 34-year-old, half-Chinese male; NF-1 was suspected at age 15 years for the first time. His medical history included preterm birth, mild facial dysmorphism, “café au lait” spots, subcutaneous and paravertebral fibromas, multifocal tachycardia, atrial fibrillation, and heart failure in early infancy. Noncalcified bone fibromas in the femur and tibia were detected at age 8 years. Surgical right leg lengthening was carried out at age 11 years. Bilateral renal artery stenosis, stenosis and aneurysm of the superior mesenteric artery, and an infrarenal aortic stenosis were detected at age 15 years. Leg edema and ectasia of the basilar artery were diagnosed at age 18 years. After an episode with an erysipela at age 34 years, he developed pericardial and pleural effusion during a 4-month period. Stenosis of the left subclavian vein at the level of thoracic duct insertion was detected. After repeated pleural punctures, pleural effusion was interpreted as chylothorax. Reduction of lymph fluid production by diet and injection of talcum into the pleural cavity had a long-term beneficial effect on the chylothorax. Leg edema and chylothorax were attributed to affliction of the lymph vessels by the NF-1. Discussion Lymphangiopathy resulting in impaired lymph fluid flow and sequestration of lymph fluid into the pleural sinus and the legs may be a rare phenotypic feature of NF-1.
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Diggs-Andrews KA, Gutmann DH. Modeling cognitive dysfunction in neurofibromatosis-1. Trends Neurosci 2013; 36:237-47. [PMID: 23312374 DOI: 10.1016/j.tins.2012.12.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/19/2012] [Accepted: 12/12/2012] [Indexed: 12/17/2022]
Abstract
Cognitive dysfunction, including significant impairments in learning, behavior, and attention, is found in over 10% of children in the general population. However, in the common inherited cancer predisposition syndrome, neurofibromatosis type 1 (NF1), the prevalence of these cognitive deficits approaches 70%. As a monogenic disorder, NF1 provides a unique genetic tool to identify and dissect mechanistically the molecular and cellular bases underlying cognitive dysfunction. In this review, we discuss Nf1 fly and mouse systems that mimic many of the cognitive abnormalities seen in children with NF1. Further, we describe discoveries from these models that have uncovered defects in the regulation of Ras activity, cAMP generation, and dopamine homeostasis as key mechanisms important for cognitive dysfunction in children with NF1.
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Affiliation(s)
- Kelly A Diggs-Andrews
- Department of Neurology, Washington University School of Medicine, Box 8111, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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Pascual-Castroviejo I, Pascual-Pascual SI. Neurofibromatosis type 1 (NF1) associated with tumor of the corpus callosum. Childs Nerv Syst 2012; 28:2177-80. [PMID: 23001021 DOI: 10.1007/s00381-012-1903-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/25/2012] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Neurofibromatosis type 1 (NF1), one of the most common neurocutaneous disorders, is a multisystemic disease associated with tumors in any organ of the body, especially in the central nervous system and also the peripheral nervous system. Pilocytic astrocytomas have been described in almost all intracranial regions in patients with NF1. However, only a few patients with NF1 and tumor of the corpus callosum have been reported to date. MATERIAL AND METHODS An 11-year-old white Spanish boy was evaluated due to a family history of NF1 and low performance test scores in school. He was studied from the neurological and intellectual level points of view. RESULTS Magnetic resonance (MR) study revealed a tumor in the anterior-middle portion of the corpus callosum and a Wechsler Intelligence Scale for Children-Revised showed verbal IQ of 92, a performance IQ of 108, and a total IQ of 100. In addition, he showed attention deficit and hyperactivity disorder. CONCLUSIONS Tumors of corpus callosum in patients with NF1 are very uncommon. The patient presented in this paper consulted due to family history of NF1, progressive hyperactivity, and below average school performance. The MR study showed tumor in the corpus callosum. Tumor histology was not investigated.
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Brems H, Pasmant E, Van Minkelen R, Wimmer K, Upadhyaya M, Legius E, Messiaen L. Review and update of SPRED1 mutations causing Legius syndrome. Hum Mutat 2012; 33:1538-46. [PMID: 22753041 DOI: 10.1002/humu.22152] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/07/2012] [Indexed: 01/24/2023]
Abstract
Legius syndrome presents as a mild neurofibromatosis type 1 (NF1) phenotype. Multiple café-au-lait spots and macrocephaly are present with or without axillary or inguinal freckling. Other typical NF1-associated features (Lisch nodules, bone abnormalities, neurofibromas, optic pathway gliomas, and malignant peripheral nerve sheath tumors) are systematically absent. Legius syndrome is caused by germline loss-of-function SPRED1 mutations, resulting in overactivation of the RAS-MAPK signal transduction cascade. The first families were identified in 2007. Here, we review all identified SPRED1 mutations and summarize molecular, clinical, and functional data. All mutations have been deposited in a database created using the Leiden Open Variation Database software and accessible at http://www.lovd.nl/SPRED1. At present, the database contains 89 different mutations identified in 146 unrelated probands, including 16 new variants described for the first time. The database contains a spectrum of mutations: 29 missense, 28 frameshift, 19 nonsense, eight copy number changes, two splicing, one silent, one in-frame deletion and a mutation affecting the initiation codon. Sixty-three mutations and deletions are definitely pathogenic or most likely pathogenic, eight SPRED1 mutations are probably benign rare variants, and 17 SPRED1 missense mutations are still unclassified and need further family and functional studies to help with the interpretation.
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Affiliation(s)
- Hilde Brems
- Department of Human Genetics, Catholic University Leuven, Leuven, Belgium
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