Diagnostic and therapeutic process of neurofibromatosis type 1 and type 2
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Neurofibromatosis is one of the most common genetic diseases. It is inherited in an autosomal dominant manner. It is divided into two genetically distinct subtypes, characterised by multiple skin lesions and tumours of the peripheral and central nervous system. Neurofibromatosis type 1, or Recklinghausen's disease, is the most common phakomatosis. The disease is genetically determined by a mutation of the neurofibromin- 1 gene on chromosome 17. Neurofibromatosis type 2 accounts for 3% of all cases. The disease is genetically determined - caused by a mutation of the neurofibromin-2 gene on chromosome 22. The diagnostic and therapeutic process of neurofibromatosis is a major challenge for clinicians. Given the complexity of the problem, we have reviewed the literature on the diagnostic and therapeutic possibilities of the disease.Keywords:
Neurofibromin 1
Neurofibromatosis type 2
Neurofibromatosis type I
Neurofibromatosis type 1, the most common phakomatoses, can present with a host of signs and symptoms, usually involving the skin and the peripheral nervous system. It is characterized by a mutation in the neurofibromatosis type 1 gene on chromosome 17q11.2 that codes for the protein neurofibromin. Neurofibromin acts as a tumor suppressor gene by inhibiting rat sarcoma (Ras) activity and its deficiency leads to increased Ras activity, cellular proliferation and tumor formation. This review was conducted to analyze the various targeted therapies at the genetic and molecular level employed to manage the tumors and other clinical presentations associated with neurofibromatosis type 1. Twenty-eight studies of treatment modalities for the conditions associated with neurofibromatosis and which involved either targeted gene therapy or molecular level therapies, including the latest advances, were included in this review. Mitogen-activated protein kinase kinase inhibition, mammalian target of Rapamycin inhibition and Tyrosine kinase inhibition, represent some of the newer treatment options in this category. Although there are a number of trials for providing therapeutic options at the genetic and molecular level for the various physical and psychological morbidities associated with neurofibromatosis type 1, most of them are in the preclinical stage. Increased clinical trials of the molecules and gene therapies could significantly help in managing the various chronic and sometimes, life-threatening conditions associated with neurofibromatosis 1 and these will probably represent the preferred treatment direction of the future.
Neurofibromin 1
Neurofibromatosis type I
Neurofibromatoses
Targeted Therapy
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1. We analysed the expression of neurofibromin mRNAs, encoded by the gene responsible for neurofibromatosis type 1, and of neurofibromin protein in nine soft tissue tumours by S1 nuclease mapping and Western blot analyses. Four tumours were obtained from patients with neurofibromatosis type 1, comprising two neurofibromas, one fibrolipoma and one malignant schwannoma, and five neurogenic tumours were obtained from non-neurofibromatosis type 1 patients. 2. All tumours, except for a malignant schwannoma, similarly expressed three species of mRNA encoding neurofibromin, an isoform with the insertion of 21 amino acids in the domain related to ras GTPase-activating protein, and an N-terminal isoform lacking this domain. 3. Western blot analysis demonstrated deficiency of neurofibromin in the tumours derived from three out of the four neurofibromatosis type 1 patients: a fibrolipoma, a malignant schwannoma and a neurofibroma. In contrast, reduction in neurofibromin was not detected in the five tumours obtained from non-neurofibromatosis type 1 patients. Furthermore, the expression of ras GTPase-activating protein was detected in all nine tumours examined. 4. The undetectable or reduced level of neurofibromin in the tumours obtained from neurofibromatosis type 1 patients suggests that this deficiency is closely related to their tumourigenesis.
Neurofibromin 1
Neurofibromatosis type I
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Neurofibromatosis type 1 (NF1) is one of the most common neurocutaneus disorders. NF1 is caused by defects in the NF1 gene, coding for the neurofibromin protein which acts as a tumor suppressor. The inheritance of NF1 is autosomal dominant.
Neurofibromin 1
Neurofibromatosis type I
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Neurofibromatosis type 1 (NF1) is an autosomal dominant condition that primarily involves the skin and the nervous system. It affects about 1 in 4000 individuals. NF1 is caused by a mutation in the nfl gene located on chromosome 17q11.2. Neurofibromin, the protein products of the normal nf1 gene, acts as a tumor suppressor and limits cell growth. Mutation in this gene leads to cell overgrowth and an increased risk of developing benign and malignant tumor. The diagnosis of NF1 is made in an individual with any two of the following clinical features: cafe-au-lait spots, intertriginous freckling, Lisch nodules, neurofibromas, optic glioma, distinctive bone lesions and first degree family relative with NF1. Learning and developmental disorders are the most common neurologic complication of neurofibromatosis type 1 and can be responsible for significant lifetime morbidity. This report provides a review on cognitive and developmental manifestation of children with NF1 and the importance of early diagnosis and treatment.
Neurofibromin 1
Intertriginous
Neurofibromatosis type I
Neurofibromatoses
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Neurofibromatosis type 1 (NF1) or von Recklinghausen neurofibromatosis is a common autosomal dominant disorder affecting 1 in 3000 individuals. The gene for NF1 is localized on chromosome 17q11.2. The gene mutations or the inactivation its protein product--neurofibromin are responsible for the manifestation of the disease. NF1 demonstrates a wide variability of clinical symptoms classified by NIH Consensus Conference in 1987.
Neurofibromin 1
Pathogenesis
Neurofibromatosis type I
Inherited disease
Neurofibromatoses
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Neurofibromatosis type 1 (NF1) is an autosomal dominant disease characterised by café-au-lait spots, freckling in the axillary or inguinal region, dermal and plexiform neurofibromas and Lisch nodules. Complications are severe in one third of patients, and the clinical variability is pronounced, even within families. The NF1 gene has been localised to chromosome 17q11.2 and encodes the protein neurofibromin. The gene is proposed to be a tumour suppressor gene. Inactivation of neurofibromin leads to a disruption in cell growth regulation. Mutation analysis is possible but laborious, and therefore NF1 is generally a clinical diagnosis based on diagnostic criteria.
Neurofibromin 1
Neurofibromatosis type I
Neurofibromatoses
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Neurofibromatosis type 1 (NF1), also known as peripheral neurofibromatosis or von Recklinghausen's disease, is one of the most common genetic disorders. It is inherited in an autosomal dominant pattern. Multiple cutaneous neurofibromas are hallmark lesions of NF1. Localized and plexiform neurofibromas of the paraspinal and sacral region are the most common abdominal neoplasms in NF1. Herein, we report two patients with a known history of NF1 presenting with multiple, extensive localized and plexiform neurofibromas. We describe the important distinguishing features of these tumors as seen on magnetic resonance imaging (MRI), including very bright signal intensity and target sign on T2 weighted images.
Plexiform neurofibroma
Neurofibromin 1
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Neurofibromatosis type 1 (NF1) is a genetic disorder associated with neurofibromin 1 (NF1) gene mutation, which predisposes for various benign and malignant tumors. Some of these tumors that frequently observed in NF1 are pilocytic astrocytomas, gastrointestinal stromal tumors, pheochromocytomas and juvenile myelomonocytic leukemia. Pheochromocytomas account for 4% of incidentally discovered adrenal tumors and 0.1 to 0.2% of hypertensive patients. Neurofibromatosis type 1 is a rare cause of pheochromocytoma. We discuss through this case and a review of the literature.
Neurofibromin 1
Neurofibromatosis type I
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The risk of malignant myeloid disorders in young children with neurofibromatosis type 1 is 200 to 500 times the normal risk. The gene for neurofibromatosis type 1 (NF1) encodes neurofibromin, a protein that negatively regulates signals transduced by Ras proteins. Genetic and biochemical data support the hypothesis that NF1 functions as a tumor-suppressor gene in immature myeloid cells, but inactivation of both NF1 alleles has not been demonstrated in leukemic cells from patients with neurofibromatosis type 1.Using an in vitro transcription and translation system, we screened bone marrow samples from 18 children with neurofibromatosis type 1 and myeloid disorders for NF1 mutations that cause a truncated protein. Mutations were confirmed by direct sequencing of genomic DNA from the patients, and from their affected parents, in cases of familial neurofibromatosis type 1.Specimens from 9 of the 18 children contained abnormal peptide fragments, and truncating mutations of the NF1 gene were found in specimens from 8 of these children. The normal NF1 allele was absent in bone marrow samples from five of the eight children. We detected the same mutation in DNA from the affected parent of each child with familial neurofibromatosis type 1.Both alleles of the NF1 gene are inactivated in leukemic cells in some patients with neurofibromatosis type 1. NF1 appears to function as a tumor-suppressor gene in immature myeloid cells.
Neurofibromin 1
Neurofibromatosis type I
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Neurofibromatosis type 1 (NF1) or von Recklinghausen disease is an inherited autosomal dominant disorder and the most common of the phakomatoses (neurocutaneous syndromes), affecting 1 in 3,000 individuals.[1][1] Pathogenesis involves mutations in the NF1 gene that encodes the protein neurofibromin
Neurofibromin 1
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Neurofibromatosis type I
Inherited disease
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