Neurofibromatosis type 1 (NF1) is a common inherited disorder with an autosomal dominant trait. We encountered an NF1 patient who showed adrenal pheochromocytoma, and analyzed expression of neurofibromin in an excised...Neurofibromatosis type 1 (NF1) is a common inherited disorder with an autosomal dominant trait. We encountered an NF1 patient who showed adrenal pheochromocytoma, and analyzed expression of neurofibromin in an excised specimen. A 54-year-old man showing multiple neurofibromas and café-au-lait spots in the skin was pointed out to have a right adrenal tumor by ultrasonography. Abdominal CT also revealed a right adrenal tumor. He was diagnosed with neurofibromatosis type 1 with no family history. Urine catecholamines, metanephrine, and normetanephrine levels were elevated. MIBG scintigraphy showed positive right adrenal uptake, and so pheochromocytoma was also diagnosed. The patient underwent laparoscopic right adrenalectomy. The excised adrenal specimen of this patient was stained with anti-neurofibromin polyclonal antibody. The NF1 pheochromocytoma was completely negative for neurofibromin protein expression, while the NF1 non-pheochromocytomatous adrenal medulla was neurofibromin-positive in the cytoplasm and nucleus. The clear discrepancy in neurofibromin expression between pheochromocytoma cells and “normal” adrenal medullary cells of the patient may well be explained by Knudson’s two-hit hypothesis.展开更多
Neurofibromatosis type 1 is a common autosomal dominant disorder with a high rate of penetrance. It is caused by the mutation of the tumor suppressor gene NF1, which encodes neurofibromin. The main function of neurofi...Neurofibromatosis type 1 is a common autosomal dominant disorder with a high rate of penetrance. It is caused by the mutation of the tumor suppressor gene NF1, which encodes neurofibromin. The main function of neurofibromin is down-regulating the biological activity of the proto-oncoprotein Ras by acting as a Ras-specific GTPase activating protein. In this study, we identified a Chinese family affected with neurofibromatosis type 1. The known gene NF1 associated with NF1 was studied by linkage analysis and by direct sequencing of the entire coding region and exon-intron boundaries of the NF1 gene. The R1947X mutation of NF1 was identified, which was co-segregated with affected individuals in the Chinese family, but not present in unaffected family members. This is the first report, which states that the R1947X mutation of NF1 may be one of reasons for neurofibromatosis type 1 in Chinese population.展开更多
AIM:To examine neuroretinal function by using the multifocal electroretinography(mf ERG)test in patients with neurofibromatosis type 1(NF1)without optic pathway gliomas(OPGs).METHODS:This study was conducted on 35 pat...AIM:To examine neuroretinal function by using the multifocal electroretinography(mf ERG)test in patients with neurofibromatosis type 1(NF1)without optic pathway gliomas(OPGs).METHODS:This study was conducted on 35 patients(35 eyes)with NF1 and 30 healthy subjects(30 eyes)for the control group.Each subject underwent a complete ophthalmological examination including spectral domainoptical coherence tomography(SD-OCT)and mf ERG.The 1.5-Tesla magnetic resonance imaging(MRI)scan of the brain was performed in NF1 patients to assess the presence of OPGs.All participants were recruited having a best corrected visual acuity(BCVA)of no less than 20/20 in each eye.The amplitude and implicit time of the P1 wave(first-order Kernel component)were evaluated on mf ERG.Data analysis was carried out in the two central degrees and in the four quadrants from two to 25 degrees of visual field.RESULTS:Statistically significant results were obtained for the P1 wave amplitudes in the 4 quadrants in NF1 patients compared to healthy controls,while the reduction was not significant in the 2 central degrees between the groups.A statistically significant difference was observed among the P1 wave amplitudes as recorded in the 4 quadrants within the NF1 group,with lower amplitudes detected in the nasal quadrants.No differences in the implicit times were recorded in the 2 central degrees and in the 4 quadrants as compared between NF1 patients and controls.CONCLUSION:Impaired neuroretinal function in NF1 patients is expressed in a decreased amplitude of the P1-wave between 2 and 25 central retinal degrees on mf ERG.Altered intracellular signal transduction due to abnormal neurofibromin-mediated cyclic adenosine monophosphate(c AMP)generation,can be involved.The possible use of mf ERG as subclinical retinal damage indicator has a potential utility in clinical practice for the follow-up of NF1 patients.展开更多
Neurofibromatosis type 1(NF1) is a common autosomal dominant disease characterized by formation of multiple benign and malignant tumors.People with this disorder also experience chronic pain,which can be disabling.Neu...Neurofibromatosis type 1(NF1) is a common autosomal dominant disease characterized by formation of multiple benign and malignant tumors.People with this disorder also experience chronic pain,which can be disabling.Neurofibromin,the protein product of the Nf1 gene,is a guanosine triphosphatase activating protein(GAP) for p21Ras(Ras).Loss of Nf1 results in an increase in activity of the Ras transduction cascade.Because of the growing evidence suggesting involvement of downstream components of the Ras transduction cascade in the sensitization of nociceptive sensory neurons,we examined the stimulus-evoked release of the neuropeptides,substance P(SP) and calcitonin gene-related peptide(CGRP),from primary sensory neurons of mice with a mutation of the Nf1 gene(Nf1+/-).Measuring the levels of SP and CGRP by radioimmunoassay,we demonstrated that capsaicinstimulated release of neuropeptides is 3-5 folds higher in spinal cord slices from Nf1+/-mice than that from wildtype mouse tissue.In addition,the potassium-and capsaicin-stimulated release of CGRP from the culture of sensory neurons isolated from Nf1+/-mice was more than double that from the culture of wildtype neurons.Using patch-clamp electrophysiological techniques,we also examined the excitability of capsaicin-sensitive sensory neurons.It was found that the number of action potentials generated by the neurons from Nf1+/-mice,responsing to a ramp of depolarizing current,was more than three times of that generated by wildtype neurons.Consistent with that observation,neurons from Nf1+/-mice had lower firing thresholds,lower rheobase currents and shorter firing latencies compared with wildtype neurons.These data clearly demonstrate that GAPs,such as neurofibromin,can alter the excitability of nociceptive sensory neurons.The augmented response of sensory neurons with altered Ras signaling may explain the abnormal pain sensations experienced by people with NF1 and suggests an important role of GAPs in the mechanism of sensory neuron sensitization.展开更多
1型神经纤维瘤病(neurofibromatosis type 1,NF1)是常见的常染色体显性遗传病之一。该疾病由NF1基因突变所引起,可累及多个系统,具有多种临床表现,包括牛奶咖啡斑、虹膜结节、神经胶质瘤、孤独症谱系障碍、学习困难、神经纤维瘤和骨骼...1型神经纤维瘤病(neurofibromatosis type 1,NF1)是常见的常染色体显性遗传病之一。该疾病由NF1基因突变所引起,可累及多个系统,具有多种临床表现,包括牛奶咖啡斑、虹膜结节、神经胶质瘤、孤独症谱系障碍、学习困难、神经纤维瘤和骨骼发育不良等。既往在NF1发病机制的研究中,多聚焦在神经纤维蛋白调控RAS信号通路。近年来,研究者开始探索除RAS信号之外的通路,挖掘神经纤维蛋白潜在功能。该文就近年来对NF1发病机制的研究进展进行综述,旨在为治疗提供新思路。展开更多
文摘Neurofibromatosis type 1 (NF1) is a common inherited disorder with an autosomal dominant trait. We encountered an NF1 patient who showed adrenal pheochromocytoma, and analyzed expression of neurofibromin in an excised specimen. A 54-year-old man showing multiple neurofibromas and café-au-lait spots in the skin was pointed out to have a right adrenal tumor by ultrasonography. Abdominal CT also revealed a right adrenal tumor. He was diagnosed with neurofibromatosis type 1 with no family history. Urine catecholamines, metanephrine, and normetanephrine levels were elevated. MIBG scintigraphy showed positive right adrenal uptake, and so pheochromocytoma was also diagnosed. The patient underwent laparoscopic right adrenalectomy. The excised adrenal specimen of this patient was stained with anti-neurofibromin polyclonal antibody. The NF1 pheochromocytoma was completely negative for neurofibromin protein expression, while the NF1 non-pheochromocytomatous adrenal medulla was neurofibromin-positive in the cytoplasm and nucleus. The clear discrepancy in neurofibromin expression between pheochromocytoma cells and “normal” adrenal medullary cells of the patient may well be explained by Knudson’s two-hit hypothesis.
基金This work was supported by the National Natural Science Foundation of China(No.30571677)the National Basic Research Program of China(973 Program)(No.2007CB512000).
文摘Neurofibromatosis type 1 is a common autosomal dominant disorder with a high rate of penetrance. It is caused by the mutation of the tumor suppressor gene NF1, which encodes neurofibromin. The main function of neurofibromin is down-regulating the biological activity of the proto-oncoprotein Ras by acting as a Ras-specific GTPase activating protein. In this study, we identified a Chinese family affected with neurofibromatosis type 1. The known gene NF1 associated with NF1 was studied by linkage analysis and by direct sequencing of the entire coding region and exon-intron boundaries of the NF1 gene. The R1947X mutation of NF1 was identified, which was co-segregated with affected individuals in the Chinese family, but not present in unaffected family members. This is the first report, which states that the R1947X mutation of NF1 may be one of reasons for neurofibromatosis type 1 in Chinese population.
文摘AIM:To examine neuroretinal function by using the multifocal electroretinography(mf ERG)test in patients with neurofibromatosis type 1(NF1)without optic pathway gliomas(OPGs).METHODS:This study was conducted on 35 patients(35 eyes)with NF1 and 30 healthy subjects(30 eyes)for the control group.Each subject underwent a complete ophthalmological examination including spectral domainoptical coherence tomography(SD-OCT)and mf ERG.The 1.5-Tesla magnetic resonance imaging(MRI)scan of the brain was performed in NF1 patients to assess the presence of OPGs.All participants were recruited having a best corrected visual acuity(BCVA)of no less than 20/20 in each eye.The amplitude and implicit time of the P1 wave(first-order Kernel component)were evaluated on mf ERG.Data analysis was carried out in the two central degrees and in the four quadrants from two to 25 degrees of visual field.RESULTS:Statistically significant results were obtained for the P1 wave amplitudes in the 4 quadrants in NF1 patients compared to healthy controls,while the reduction was not significant in the 2 central degrees between the groups.A statistically significant difference was observed among the P1 wave amplitudes as recorded in the 4 quadrants within the NF1 group,with lower amplitudes detected in the nasal quadrants.No differences in the implicit times were recorded in the 2 central degrees and in the 4 quadrants as compared between NF1 patients and controls.CONCLUSION:Impaired neuroretinal function in NF1 patients is expressed in a decreased amplitude of the P1-wave between 2 and 25 central retinal degrees on mf ERG.Altered intracellular signal transduction due to abnormal neurofibromin-mediated cyclic adenosine monophosphate(c AMP)generation,can be involved.The possible use of mf ERG as subclinical retinal damage indicator has a potential utility in clinical practice for the follow-up of NF1 patients.
文摘Neurofibromatosis type 1(NF1) is a common autosomal dominant disease characterized by formation of multiple benign and malignant tumors.People with this disorder also experience chronic pain,which can be disabling.Neurofibromin,the protein product of the Nf1 gene,is a guanosine triphosphatase activating protein(GAP) for p21Ras(Ras).Loss of Nf1 results in an increase in activity of the Ras transduction cascade.Because of the growing evidence suggesting involvement of downstream components of the Ras transduction cascade in the sensitization of nociceptive sensory neurons,we examined the stimulus-evoked release of the neuropeptides,substance P(SP) and calcitonin gene-related peptide(CGRP),from primary sensory neurons of mice with a mutation of the Nf1 gene(Nf1+/-).Measuring the levels of SP and CGRP by radioimmunoassay,we demonstrated that capsaicinstimulated release of neuropeptides is 3-5 folds higher in spinal cord slices from Nf1+/-mice than that from wildtype mouse tissue.In addition,the potassium-and capsaicin-stimulated release of CGRP from the culture of sensory neurons isolated from Nf1+/-mice was more than double that from the culture of wildtype neurons.Using patch-clamp electrophysiological techniques,we also examined the excitability of capsaicin-sensitive sensory neurons.It was found that the number of action potentials generated by the neurons from Nf1+/-mice,responsing to a ramp of depolarizing current,was more than three times of that generated by wildtype neurons.Consistent with that observation,neurons from Nf1+/-mice had lower firing thresholds,lower rheobase currents and shorter firing latencies compared with wildtype neurons.These data clearly demonstrate that GAPs,such as neurofibromin,can alter the excitability of nociceptive sensory neurons.The augmented response of sensory neurons with altered Ras signaling may explain the abnormal pain sensations experienced by people with NF1 and suggests an important role of GAPs in the mechanism of sensory neuron sensitization.
文摘1型神经纤维瘤病(neurofibromatosis type 1,NF1)是常见的常染色体显性遗传病之一。该疾病由NF1基因突变所引起,可累及多个系统,具有多种临床表现,包括牛奶咖啡斑、虹膜结节、神经胶质瘤、孤独症谱系障碍、学习困难、神经纤维瘤和骨骼发育不良等。既往在NF1发病机制的研究中,多聚焦在神经纤维蛋白调控RAS信号通路。近年来,研究者开始探索除RAS信号之外的通路,挖掘神经纤维蛋白潜在功能。该文就近年来对NF1发病机制的研究进展进行综述,旨在为治疗提供新思路。
