scholarly journals Application of Combined Long Amplicon Sequencing (CoLAS) for Genetic Analysis of Neurofibromatosis Type 1: A Pilot Study

2021 ◽  
Vol 43 (2) ◽  
pp. 782-801
Author(s):  
Sumihito Togi ◽  
Hiroki Ura ◽  
Yo Niida

Elaborate analyses of the status of gene mutations in neurofibromatosis type 1 (NF1) are still difficult nowadays due to the large gene sizes, broad mutation spectrum, and the various effects of mutations on mRNA splicing. These problems cannot be solved simply by sequencing the entire coding region using next-generation sequencing (NGS). We recently developed a new strategy, named combined long amplicon sequencing (CoLAS), which is a method for simultaneously analysing the whole genomic DNA region and, also, the full-length cDNA of the disease-causative gene with long-range PCR-based NGS. In this study, CoLAS was specifically arranged for NF1 genetic analysis, then applied to 20 patients (five previously reported and 15 newly recruited patients, including suspicious cases) for optimising the method and to verify its efficacy and benefits. Among new cases, CoLAS detected not only 10 mutations, including three unreported mutations and one mosaic mutation, but also various splicing abnormalities and allelic expression ratios quantitatively. In addition, heterozygous mapping by polymorphisms, including introns, showed copy number monitoring of the entire NF1 gene region was possible in the majority of patients tested. Moreover, it was shown that, when a chromosomal level microdeletion was suspected from heterozygous mapping, it could be detected directly by breakpoint-specific long PCR. In conclusion, CoLAS not simply detect the causative mutation but accurately elucidated the entire structure of the NF1 gene, its mRNA expression, and also the splicing status, which reinforces its high usefulness in the gene analysis of NF1.

2021 ◽  
Vol 23 (1) ◽  
pp. 352
Author(s):  
Maximilian Scheer ◽  
Sandra Leisz ◽  
Eberhard Sorge ◽  
Olha Storozhuk ◽  
Julian Prell ◽  
...  

Neurofibromatosis type 1 (NF1) gene mutations or alterations occur within neurofibromatosis type 1 as well as in many different malignant tumours on the somatic level. In glioblastoma, NF1 loss of function plays a major role in inducing the mesenchymal (MES) subtype and, therefore defining the most aggressive glioblastoma. This is associated with an immune signature and mediated via the NF1–MAPK–FOSL1 axis. Specifically, increased invasion seems to be regulated via mutations in the leucine-rich domain (LRD) of the NF1 gene product neurofibromin. Novel targets for therapy may arise from neurofibromin deficiency-associated cellular mechanisms that are summarised in this review.


2021 ◽  
Vol 12 ◽  
Author(s):  
Wei Wang ◽  
Cheng-Jiang Wei ◽  
Xi-Wei Cui ◽  
Yue-Hua Li ◽  
Yi-Hui Gu ◽  
...  

Neurofibromatosis type 1 (NF1) is a tumor predisposition genetic disorder that directly affects more than 1 in 3,000 individuals worldwide. It results from mutations of the NF1 gene and shows almost complete penetrance. NF1 patients show high phenotypic variabilities, including cafe-au-lait macules, freckling, or other neoplastic or non-neoplastic features. Understanding the underlying mechanisms of the diversities of clinical symptoms might contribute to the development of personalized healthcare for NF1 patients. Currently, studies have shown that the different types of mutations in the NF1 gene might correlate with this phenomenon. In addition, genetic modifiers are responsible for the different clinical features. In this review, we summarize different genetic mutations of the NF1 gene and related genetic modifiers. More importantly, we focus on the genotype–phenotype correlation. This review suggests a novel aspect to explain the underlying mechanisms of phenotypic heterogeneity of NF1 and provides suggestions for possible novel therapeutic targets to prevent or delay the onset and development of different manifestations of NF1.


1993 ◽  
Vol 92 (4) ◽  
pp. 429-430 ◽  
Author(s):  
Conxi L�zaro ◽  
Antonia Gaona ◽  
Ganfeng Xu ◽  
Robert Weiss ◽  
Xavier Estivill

Author(s):  
Nahla Abdel‐Aziz ◽  
Ghada El‐Kamah ◽  
Rabab Khairat ◽  
Hanan Mohamed ◽  
Yehia Gad ◽  
...  

1994 ◽  
Vol 94 (1) ◽  
pp. 97-100 ◽  
Author(s):  
Sven Hoffmeyer ◽  
Günter Assum ◽  
Dieter Kaufmann ◽  
Kirsten Schwenk ◽  
Winfrid Krone

2018 ◽  
Vol 178 (2) ◽  
pp. K1-K9 ◽  
Author(s):  
Laura Gieldon ◽  
Jimmy Rusdian Masjkur ◽  
Susan Richter ◽  
Roland Därr ◽  
Marcos Lahera ◽  
...  

Objective Our objective was to improve molecular diagnostics in patients with hereditary pheochromocytoma and paraganglioma (PPGL) by using next-generation sequencing (NGS) multi-gene panel analysis. Derived from this study, we here present three cases that were diagnosed with NF1 germline mutations but did not have a prior clinical diagnosis of neurofibromatosis type 1 (NF1). Design We performed genetic analysis of known tumor predisposition genes, including NF1, using a multi-gene NGS enrichment-based panel applied to a total of 1029 PPGL patients. We did not exclude genes known to cause clinically defined syndromes such as NF1 based on missing phenotypic expression as is commonly practiced. Methods Genetic analysis was performed using NGS (TruSight Cancer Panel/customized panel by Illumina) for analyzing patients’ blood and tumor samples. Validation was carried out by Sanger sequencing. Results Within our cohort, three patients, who were identified to carry pathogenic NF1 germline mutations, attracted attention, since none of the patients had a clinical suspicion of NF1 and one of them was initially suspected to have MEN2A syndrome due to co-occurrence of a medullary thyroid carcinoma. In these cases, one splice site, one stop and one frameshift mutation in NF1 were identified. Conclusions Since phenotypical presentation of NF1 is highly variable, we suggest analysis of the NF1 gene also in PPGL patients who do not meet diagnostic NF1 criteria. Co-occurrence of medullary thyroid carcinoma and PPGL was found to be a clinical decoy in NF1 diagnostics. These observations underline the value of multi-gene panel NGS for PPGL patients.


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