scholarly journals Identification of a Novel EXT Mutation in A Kindred With Hereditary Multiple Exostoses Using Whole-Exome Sequencing and Overview of Mutation Spectrum

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.

2019 ◽  
Author(s):  
Mei Sim Lung ◽  
Catherine A. Mitchell ◽  
Maria A. Doyle ◽  
Andrew C. Lynch ◽  
Kylie L. Gorringe ◽  
...  

Abstract Background Familial cases of appendiceal mucinous tumours (AMTs) are extremely rare and the underlying genetic aetiology uncertain. We identified potential predisposing germline genetic variants in a father and daughter with AMTs presenting with pseudomyxoma peritonei (PMP) and correlated these with regions of loss of heterozygosity (LOH) in the tumours. Materials and Methods Through germline whole exome sequencing, we identified novel heterozygous loss-of-function (LoF) (i.e. nonsense, frameshift and essential splice site mutations) and missense variants shared between father and daughter, and validated all LoF variants, and missense variants with a Combined Annotation Dependent Depletion (CADD) scaled score of ≥10. Genome-wide copy number analysis was performed on tumour tissue from both individuals to identify regions of LOH. Results Seventeen novel variants in 17 genes were shared by the father and daughter: a nonsense mutation in REEP5 , an essential splice site mutation in THOP1 , and 15 missense variants. None of these germline variants were located in tumour regions of LOH shared by the father and daughter. Four genes ( EXOG , RANBP2, RANBP6 and TNFRSF1B ) harboured missense variants that fell in a region of LOH in the tumour from the father only, but none showed somatic loss of the wild type allele in the tumour. The REEP5 gene was sequenced in 23 individuals with presumed sporadic PMP; no LoF or rare missense germline variants were identified. Conclusion Germline exome sequencing of a father and daughter with AMTs identified novel candidate predisposing genes. Further studies are required to clarify the role of these genes in familial AMTs.


2020 ◽  
Vol 12 (3) ◽  
pp. 990-996
Author(s):  
Chao Liang ◽  
Yong‐jie Wang ◽  
Yu‐xuan Wei ◽  
Yang Dong ◽  
Zhi‐chang Zhang

2020 ◽  
Author(s):  
YiQiang Li ◽  
XueMei Lin ◽  
MingWei Zhu ◽  
FuXing Xun ◽  
JingChun Li ◽  
...  

Abstract Background: Although the main causative genes for hereditary multiple exostoses (HME) are EXT-1 and EXT-2, there are still many HME patients without EXT-1 and EXT-2 mutations. This study aimed to identify novel candidate genes for the development of HME in patients without EXT-1 and EXT-2 mutations.Methods: Whole-exome sequencing was performed in a typical Chinese HME family without EXT-1 and EXT-2 mutations, followed by a combined bioinformatics pipeline including annotation and filtering process to identify candidate variants. Candidate variants were then validated by Sanger sequencing.Results: A total of 1830 original variants were revealed to be heterozygous mutations in the three patients suffering from HME that were not present in the healthy controls. Two mutations (c.C1849T in SLC20A2 and c.G506A in LETM1) were identified as a possible causative variant for HME through a bioinformatics filtering procedure and harmful prediction. Sanger sequencing results confirmed these two mutations in all patients with HME. A mutation in SLC20A2 (c.C1849T) led to a change in amino acid (p.R617C), which may be involved in the development of HME by inducing metabolic disorders of phosphate and abnormal proliferation and differentiation in chondrocytes.Conclusions: The present study revealed two mutations [SLC20A2 (c.C1849T) and LETM1 (c.G506A) in a Chinese HME family. The mutation in SLC20A2 (c.C1849T) is more likely to be involved in the development of HME.


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.


2021 ◽  
Author(s):  
Peng Tu ◽  
Hairui Sun ◽  
Xiaohang Zhang ◽  
Qian Ran ◽  
suzhen Ran ◽  
...  

Abstract Background: Left ventricular non-compaction cardiomyopathy (LVNC) is a rare congenital heart defect (CHD), genetics defects have been found in patients with LVNC and their family members; and MYH7 is the most common genetic associated with LVNC. Methods: A trio (fetus and the parents) whole-exome sequencing (WES) was performed when the fetus was found with Ebstein's anomaly (EA), heart dilatation, perimembranous ventricular septal defects (VSD), mild seroperitoneum and single umbilical artery (SUA).Results: Whole-exome sequencing identified a maternal inherited heterozygous splice site mutation in MYH7 (NM_000257.3:c.732+1G>A). Subsequent Sanger sequencing confirmed that the mutation was heterozygous in the fetus, the old sister, the grandmother, and the mother. QPCR experiment using RNA from blood lymphocytes but were unable to amplify any product.Conclusion: This familial case underlines that the striking cardiac phenotypic of MYH7 mutation (the c.732+1G>A spice site variant) may be highly variable. The mechanistic studies which could uncover candidate genes modulating cardiac phenotype associated with LVNC/EA should be proceed.


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.


2021 ◽  
Author(s):  
Rui Zhang ◽  
Yajing Hao ◽  
Ying Xu ◽  
Jiale Qin ◽  
Yanfang Wang ◽  
...  

Abstract Background: Isolated sulfite oxidase deficiency (ISOD) is the rarest types of life-threatening neurometabolic disorders characterized by neonatal intractable seizures and severe developmental delay with an autosomal recessive mode of inheritance. ISOD is extremely rare and till date only 32 mutations have been identified and reported worldwide. Germline mutation in SUOX gene causes ISOD. Methods: Here, we investigated a 5-days old Chinese female child, presented with intermittent tremor or seizures of limbs, neonatal encephalopathy, subarachnoid cyst and haemorrhage, dysplasia of corpus callosum, neonatal convulsion, respiratory failure, cardiac failure, hyperlactatemia, severe metabolic acidosis, hyperglycemia, hyperkalemia, moderate anemia, atrioventricular block and complete right bundle branch block. Results: Whole exome sequencing identified a novel homozygous transition (c.1227G>A) in exon 6 of the SUOX gene in the proband. This novel homozygous variant leads to the formation of a truncated sulfite oxidase (p.Trp409*) of 408 amino acids. Hence, it is a loss-of-function variant. Proband’s father and mother is carrying this novel variant in a heterozygous state. This variant was not identified in 200 ethnically matched normal healthy control individuals. Conclusions: Our study not only expand the mutational spectrum of SUOX gene associated ISOD, but also strongly suggested the application of whole exome sequencing for identifying candidate genes and novel disease-causing mutations.


2019 ◽  
Vol 25 (11) ◽  
pp. 1788-1795 ◽  
Author(s):  
Thomas Magg ◽  
Anna Shcherbina ◽  
Duran Arslan ◽  
Mukesh M Desai ◽  
Sarah Wall ◽  
...  

Abstract Background Children with very early onset inflammatory bowel diseases (VEO-IBD) often have a refractory and severe disease course. A significant number of described VEO-IBD-causing monogenic disorders can be attributed to defects in immune-related genes. The diagnosis of the underlying primary immunodeficiency (PID) often has critical implications for the treatment of patients with IBD-like phenotypes. Methods To identify the molecular etiology in 5 patients from 3 unrelated kindred with IBD-like symptoms, we conducted whole exome sequencing. Immune workup confirmed an underlying PID. Results Whole exome sequencing revealed 3 novel CARMIL2 loss-of-function mutations in our patients. Immunophenotyping of peripheral blood mononuclear cells showed reduction of regulatory and effector memory T cells and impaired B cell class switching. The T cell proliferation and activation assays confirmed defective responses to CD28 costimulation, consistent with CARMIL2 deficiency. Conclusion Our study highlights that human CARMIL2 deficiency can manifest with IBD-like symptoms. This example illustrates that early diagnosis of underlying PID is crucial for the treatment and prognosis of children with VEO-IBD.


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