scholarly journals Identifying Possible Candidate Factors Influencing the Penetrance of Heterozygous NFKB1 Loss of Function Mutations By Whole Exome Sequencing

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3706-3706
Author(s):  
Cyrill Schipp ◽  
Arndt Borkhardt ◽  
Polina Stepensky ◽  
Ute Fischer

Abstract Introduction The NFκB signaling pathway is a master regulator of immune and inflammatory responses. Recently we and other groups reported heterozygous NFKB1 loss-of-function mutations in patients with combined variable immunodeficiency (CVID) characterized by recurrent infections, autoimmunity and immunoglobulin deficiency. Pedigree analysis revealed incomplete penetrance of the disease causing mutation in 5 of the 6 analyzed families. While patients showed a severe phenotype including hypogammaglobulinemia, chronic infections and cytopenias, other carriers of the same mutation were unaffected except for slightly perturbed immunoglobulin levels indicating the existence of other factors influencing the penetrance of these mutations. Methods To identify genetic factors associated with complete penetrance of dominant NFKB1 mutations, whole exome sequencing was carried out using DNA extracted from blood samples derived from two patients and their families. Sequencing data of two patients and X unaffected carriers of the same NFKB1 mutations (p.R157X and p.I47fsX2) were then screened in silico for single nucleotide variations, small insertions and deletions present in modulators of immune responses in general and the NFκB pathway in particular, employing lists generated based on publicly available data on gene interactions (including e.g. data of the KEGG, and STRING databases). Results We detected no deleterious mutations in known modifier genes such as IL10, IL1B, IL6, CCR5, CCL5, RANTES, TGFB1 and others. But strikingly both patients harbored two polymorphisms (g.797C>A, Gly54Asp, Gly57Glu) in the Mannose Binding Lectin 2 (MBL2) gene that were previously reported as disease causing mutations in patients with primary immunodeficiency. These polymorphisms lead to reduced MBL2 expression and are linked with high susceptibility to infections. We hypothesize that low MBL2 expression in an NFKB1 haploinsufficient background may promote disease penetrance or increase the predisposition to infections. Conclusion Our combined next-generation sequencing and bioinformatics analyses approach identified MBL2 as an interesting candidate factor whose deficient expression may influence the penetrance of NFKB1 loss-of-function mutations. Further analysis of greater cohorts is needed to reinforce the role of MBL2 in the pathogenesis of NFKB1 haploinsufficiency. Disclosures No relevant conflicts of interest to declare.

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 220-220
Author(s):  
Charuta Gavankar Furey ◽  
Jungmin Choi ◽  
Daniel Duran ◽  
Andrew T Timberlake ◽  
Xue Zeng ◽  
...  

Abstract INTRODUCTION Congenital hydrocephalus (CH), with an estimated prevalence of 1 in 1000 births, is the most common disease treated by pediatric neurosurgeons, and exerts a tremendous burden on the United States health care budget, consuming over $2 billion annually. Paradoxically, CH treatments remain inadequate, crude, and primarily symptomatic, comprised largely of surgical shunts riddled with infectious and mechanical complications. Despite evidence that genetic factors play a major role in the pathogenesis of CH an estimated 40% of human CH has a genetic etiology our knowledge of specific CH-causing mutations and their pathogenic mechanisms remains primitive. Understanding critical genetic drivers underlying human CH holds promise for the development of targeted therapies. However, traditional genetic approaches have been limited in their ability to identify causative CH genes because kindreds are rare, small in size, or appear to have sporadic inheritance patterns. Next-generation sequencing, and specifically whole exome sequencing (WES), can overcome these barriers to gene discovery. METHODS We performed whole-exome sequencing on DNA isolated from 130 patient-parent trios (affected patient and unaffected parents) and an additional 57 probands for a total of 187 CH patients with non-L1CAM primary CH. Exome-sequencing data from these 447 individuals was then analyzed to identify rare, de novo and transmitted mutations contributing to CH, and candidate mutations were subsequently confirmed by Sanger sequencing. RESULTS >Exome sequencing identified multiple novel and recurrent de novo and transmitted loss-of function gene mutations enriched in neurodevelopmental and ciliogenesis pathways. Binomial and case-control analyses confirmed exome-wide statistical significance of candidate genes, and functional modeling in Xenopus established gene causality. CONCLUSION These findings reveal novel disease-causing mutations in human CH, thereby providing new opportunities for improved prognostic assessment and non-invasive therapies.


2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jennifer D. Hintzsche ◽  
William A. Robinson ◽  
Aik Choon Tan

Whole Exome Sequencing (WES) is the application of the next-generation technology to determine the variations in the exome and is becoming a standard approach in studying genetic variants in diseases. Understanding the exomes of individuals at single base resolution allows the identification of actionable mutations for disease treatment and management. WES technologies have shifted the bottleneck in experimental data production to computationally intensive informatics-based data analysis. Novel computational tools and methods have been developed to analyze and interpret WES data. Here, we review some of the current tools that are being used to analyze WES data. These tools range from the alignment of raw sequencing reads all the way to linking variants to actionable therapeutics. Strengths and weaknesses of each tool are discussed for the purpose of helping researchers make more informative decisions on selecting the best tools to analyze their WES data.


Neurology ◽  
2018 ◽  
Vol 91 (23) ◽  
pp. e2170-e2181 ◽  
Author(s):  
Oswaldo Lorenzo-Betancor ◽  
Patrick R. Blackburn ◽  
Emily Edwards ◽  
Rocío Vázquez-do-Campo ◽  
Eric W. Klee ◽  
...  

ObjectiveTo identify novel genes involved in the etiology of intracranial aneurysms (IAs) or subarachnoid hemorrhages (SAHs) using whole-exome sequencing.MethodsWe performed whole-exome sequencing in 13 individuals from 3 families with an autosomal dominant IA/SAH inheritance pattern to look for candidate genes for disease. In addition, we sequenced PCNT exon 38 in a further 161 idiopathic patients with IA/SAH to find additional carriers of potential pathogenic variants.ResultsWe identified 2 different variants in exon 38 from the PCNT gene shared between affected members from 2 different families with either IA or SAH (p.R2728C and p.V2811L). One hundred sixty-four samples with either SAH or IA were Sanger sequenced for the PCNT exon 38. Five additional missense mutations were identified. We also found a second p.V2811L carrier in a family with a history of neurovascular diseases.ConclusionThe PCNT gene encodes a protein that is involved in the process of microtubule nucleation and organization in interphase and mitosis. Biallelic loss-of-function mutations in PCNT cause a form of primordial dwarfism (microcephalic osteodysplastic primordial dwarfism type II), and ≈50% of these patients will develop neurovascular abnormalities, including IAs and SAHs. In addition, a complete Pcnt knockout mouse model (Pcnt−/−) published previously showed general vascular abnormalities, including intracranial hemorrhage. The variants in our families lie in the highly conserved PCNT protein-protein interaction domain, making PCNT a highly plausible candidate gene in cerebrovascular disease.


2017 ◽  
Vol 33 (15) ◽  
pp. 2402-2404 ◽  
Author(s):  
Alessandro Romanel ◽  
Tuo Zhang ◽  
Olivier Elemento ◽  
Francesca Demichelis

2021 ◽  
Author(s):  
yanhan deng ◽  
yujian liu ◽  
wei tu ◽  
liu yang

Abstract Background: Hereditary Multiple Osteochondromas(HMO) is a rare genetic musculoskeletal disorder characterized by multiple osteochondromas that form near to the growth plates of many bones. Loss-of-function mutations in EXT1 or EXT2 that encode glycosyltrasferases are the causal mutations for most HMO patients.Methods: After collecting the family history and clinical information, we used Whole-Exome Sequencing to find the pathogenic mutations in one Chinese Hereditary Multiple Exostoses pedigree. Sanger sequencing and relevant online databases were used to validate the screened variants. Lollipop plots were drew to map the reported mutations from online databases (Multiple Osteochondroma Mutation Database and clinvar)on a linear protein domains by MutationMapper.Results: A novel heterozygous splicing-site mutation in gene EXT1 (NM_000127:exon5:c.1417+1G>C,chr8:118834703) was found in this pedigree and mutation spectrum of genes EXT1 and EXT2 were demonstrated.Conclusions: Our results help this pedigree to identify the pathogenic variant and guide the prenatal diagnosis, also expand the mutation spectrum in Hereditary Multiple Osteochondromas.


2020 ◽  
Author(s):  
Chih-Fen Hu ◽  
G. W. Gant Luxton ◽  
Feng-Chin Lee ◽  
Chih-Sin Hsu ◽  
Shih-Ming Huang ◽  
...  

AbstractBackgroundDYT1 dystonia is a neurological movement disorder characterized by painful sustained muscle contractions resulting in abnormal twisting and postures. In a subset of patients, it is caused by a loss-of-function mutation (ΔE302/303; or ΔE) in the luminal ATPases associated with various cellular activities (AAA+) protein torsinA encoded by the TOR1A gene. The low penetrance of the ΔE mutation (∼30-40%) suggests the existence of unknown genetic modifiers of DYT1 dystonia.MethodsTo identify these modifiers, we performed whole exome sequencing of blood leukocyte DNA isolated from two DYT1 dystonia patients, three asymptomatic carriers of the ΔE mutation, and an unaffected adult relative.ResultsA total of 264 DYT1 dystonia-associated variants (DYT1 variants) were identified in 195 genes. Consistent with the emerging view of torsinA as an important regulator of the cytoskeleton, endoplasmic reticulum homeostasis, and lipid metabolism, we found DYT1 variants in genes that encode proteins implicated in these processes. Moreover, 40 DYT1 variants were detected in 32 genes associated with neuromuscular and neuropsychiatric disorders.ConclusionThe DYT1 variants described in this work represent exciting new targets for future studies designed to increase our understanding of the pathophysiology and pathogenesis of DYT1 dystonia.


2018 ◽  
Vol 103 (6) ◽  
pp. 761-767 ◽  
Author(s):  
Laura Bryant ◽  
Olga Lozynska ◽  
Anson Marsh ◽  
Tyler E Papp ◽  
Lucas van Gorder ◽  
...  

BackgroundVariants in PRPF31, which encodes pre-mRNA processing factor 31 homolog, are known to cause autosomal-dominant retinitis pigmentosa (adRP) with incomplete penetrance. However, the majority of mutations cause null alleles, with only two proven pathogenic missense mutations. We identified a novel missense mutation in PRPF31 in a family with adRP.MethodsWe performed whole exome sequencing to identify possible pathogenic mutations in the proband of a family with adRP. Available affected family members had a full ophthalmological evaluation including kinetic and two-colour dark adapted static perimetry, electroretinography and multimodal imaging of the retina. Two patients had evaluations covering nearly 20 years. We carried out segregation analysis of the probable mutation, PRPF31 c.590T>C. We evaluated the cellular localisation of the PRPF31 variant (p.Leu197Pro) compared with the wildtype PRPF31 protein.ResultsPRPF31 c.590T>C segregated with the disease in this four-generation autosomal dominant pedigree. There was intrafamilial variability in disease severity. Nyctalopia and mid-peripheral scotomas presented from the second to the fourth decade of life. There was severe rod >cone dysfunction. Visual acuity (VA) was relatively intact and was maintained until later in life, although with marked interocular asymmetries. Laboratory studies showed that the mutant PRPF31 protein (p.Leu197Pro) does not localise to the nucleus, unlike the wildtype PRPF31 protein. Instead, mutant protein resulted in punctate localisation to the cytoplasm.Conclusionsc.590T>C is a novel pathogenic variant in PRPF31 causing adRP with incomplete penetrance. Disease may be due to protein misfolding and associated abnormal protein trafficking to the nucleus.


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