scholarly journals Genetic Survey of Autosomal Recessive Peripheral Neuropathy Cases Unravels High Genetic Heterogeneity in a Turkish Cohort

2021 ◽  
Vol 7 (5) ◽  
pp. e621
Author(s):  
Ayşe Candayan ◽  
Arman Çakar ◽  
Gulshan Yunisova ◽  
Ayşe Nur Özdağ Acarlı ◽  
Derek Atkinson ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Candidate Genes ◽  
Whole Exome Sequencing ◽  
Autosomal Recessive ◽  
Axonal Neuropathy ◽  
Genetic Diagnosis ◽  
Clinical Feature ◽  
Whole Exome ◽  
Recurrent Mutations ◽  
Diagnosis Rate

Background and ObjectivesInherited peripheral neuropathies (IPNs) are a group of genetic disorders of the peripheral nervous system in which neuropathy is the only or the most predominant clinical feature. The most common type of IPN is Charcot-Marie-Tooth (CMT) disease. Autosomal recessive CMT (ARCMT) is generally more severe than dominant CMT and its genetic basis is poorly understood due to high clinical and genetic diversity. Here, we report clinical and genetic findings from 56 consanguineous Turkish families initially diagnosed with CMT disease.MethodsWe initially screened the GDAP1 gene in our cohort as it is the most commonly mutated ARCMT gene. Next, whole-exome sequencing and homozygosity mapping based on whole-exome sequencing (HOMWES) analysis was performed. To understand the molecular impact of candidate causative genes, functional analyses were performed in patient primary fibroblasts.ResultsBiallelic recurrent mutations in the GDAP1 gene have been identified in 6 patients. Whole-exome sequencing and HOMWES analysis revealed 16 recurrent and 13 novel disease-causing alleles in known IPN-related genes and 2 novel candidate genes: 1 for a CMT-like disease and 1 for autosomal recessive cerebellar ataxia with axonal neuropathy. We have achieved a potential genetic diagnosis rate of 62.5% (35/56 families) in our cohort. Considering only the variants that meet the American College for Medical Genetics and Genomics (ACMG) classification as pathogenic or likely pathogenic, the definitive diagnosis rate was 55.35% (31/56 families).DiscussionThis study paints a genetic landscape of the Turkish ARCMT population and reports additional candidate genes that might help enlighten the mechanism of pathogenesis of the disease.

Utility of Whole Exome Sequencing for Genetic Diagnosis of Previously Undiagnosed Pediatric Neurology Patients

2016 ◽  
Vol 31 (14) ◽  
pp. 1534-1539 ◽  
Author(s):  
Maya Kuperberg ◽  
Dorit Lev ◽  
Lubov Blumkin ◽  
Ayelet Zerem ◽  
Mira Ginsberg ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Autosomal Recessive ◽  
Genetic Diagnosis ◽  
Clinical Feature ◽  
Causative Gene ◽  
High Detection Rate ◽  
Whole Exome ◽  
Neurological Patients ◽  
Low Costs

Whole exome sequencing enables scanning a large number of genes for relatively low costs. The authors investigate its use for previously undiagnosed pediatric neurological patients. This retrospective cohort study performed whole exome sequencing on 57 patients of “Magen” neurogenetic clinics, with unknown diagnoses despite previous workup. The authors report on clinical features, causative genes, and treatment modifications and provide an analysis of whole exome sequencing utility per primary clinical feature. A causative gene was identified in 49.1% of patients, of which 17 had an autosomal dominant mutation, 9 autosomal recessive, and 2 X-linked. The highest rate of positive diagnosis was found for patients with developmental delay, ataxia, or suspected neuromuscular disease. Whole exome sequencing warranted a definitive change of treatment for 5 patients. Genetic databases were updated accordingly. In conclusion, whole exome sequencing is useful in obtaining a high detection rate for previously undiagnosed disorders. Use of this technique could affect diagnosis, treatment, and prognostics for both patients and relatives.

scholarly journals Searching for the missing genetic determinants of hereditary breast cancer risk by whole-exome sequencing of BRCA-negative patients: new candidate genes USP39, SLIT3, CREB3

2021 ◽  
Vol 67 (1) ◽  
pp. 111-116
Author(s):  
Kirill Zagorodnev ◽  
Aleksandr Romanko ◽  
Uliy Gorgul ◽  
Aleksandr Ivantsov ◽  
Anna Sokolenko ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Exome Sequencing ◽  
Candidate Genes ◽  
Whole Exome Sequencing ◽  
Hereditary Breast Cancer ◽  
Germ Line ◽  
Genetic Diagnosis ◽  
Clinical Signs ◽  
Causative Mutation ◽  
Whole Exome

The search for the new hereditary mutations and a precise molecular genetic diagnosis that determines the causative mutation in each specific case of hereditary breast cancer (BC) is a clinically important task since it helps to define the personal therapeutic approach and increase the effectiveness of preventive measures. Using whole-exome sequencing (WES) we analyzed the full spectrum of hereditary variations in 49 Russian patients with clinical signs of a hereditary disease which allowed us to compile a list of 229 candidate probably pathogenic germ-line variants. Then, the selected candidate mutations were validated by Sanger sequencing and molecular-epidemiological studies, the predisposing roles of three oncologically relevant mutations (USP39 c.*208G>C, SLIT3 p.Arg154Cys, and CREB3 p.Lys157Glu) were confirmed. Our candidate genes are first mentioned in connection with the hereditary risk of BC. The final proofs of the causative roles of these variants could be obtained through functional tests as well as via the analysis of the mutations segregation in BC families.

A Novel Homozygous SACS Mutation Identified by Whole-Exome Sequencing in a Consanguineous Family with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay

2017 ◽  
Vol 152 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Hui Zeng ◽  
Jian-Guang Tang ◽  
Yi-Feng Yang ◽  
Zhi-Ping Tan ◽  
Jie-Qiong Tan
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Autosomal Recessive ◽  
Genetic Diagnosis ◽  
Homozygous Deletion ◽  
Consanguineous Family ◽  
Spastic Ataxia ◽  
Whole Exome ◽  
Family Based ◽  
Classical Triad

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a hereditary neurological disorder mostly manifested with a classical triad: progressive early-onset cerebellar ataxia, lower limb pyramidal signs, and peripheral neuropathy. We employed whole-exome sequencing and bioinformatics to identify the genetic cause in an ARSACS patient from a consanguineous family. Based on whole-exome sequences of the patient and her healthy parents, a novel homozygous deletion variant (NM_014363: c.9495_9508del; p.F3166Tfs*9) in the SACS gene was identified in the patient. This frameshift mutation is predicted to generate a truncated sacsin protein, which results in the loss of the C-terminal 1,406 amino acids. Our study provides a potential genetic diagnosis for the patient and expands the spectrum of SACS mutations.

scholarly journals Exome sequencing in paediatric patients with movement disorders

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Anna Ka-Yee Kwong ◽  
Mandy Ho-Yin Tsang ◽  
Jasmine Lee-Fong Fung ◽  
Christopher Chun-Yu Mak ◽  
Kate Lok-San Chan ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Movement Disorders ◽  
Rare Variants ◽  
Diagnostic Yield ◽  
Neurological Diseases ◽  
Genetic Diagnosis ◽  
Potential Treatment ◽  
Paediatric Patients ◽  
Whole Exome

Abstract Background Movement disorders are a group of heterogeneous neurological diseases including hyperkinetic disorders with unwanted excess movements and hypokinetic disorders with reduction in the degree of movements. The objective of our study is to investigate the genetic etiology of a cohort of paediatric patients with movement disorders by whole exome sequencing and to review the potential treatment implications after a genetic diagnosis. Results We studied a cohort of 31 patients who have paediatric-onset movement disorders with unrevealing etiologies. Whole exome sequencing was performed and rare variants were interrogated for pathogenicity. Genetic diagnoses have been confirmed in 10 patients with disease-causing variants in CTNNB1, SPAST, ATP1A3, PURA, SLC2A1, KMT2B, ACTB, GNAO1 and SPG11. 80% (8/10) of patients with genetic diagnosis have potential treatment implications and treatments have been offered to them. One patient with KMT2B dystonia showed clinical improvement with decrease in dystonia after receiving globus pallidus interna deep brain stimulation. Conclusions A diagnostic yield of 32% (10/31) was reported in our cohort and this allows a better prediction of prognosis and contributes to a more effective clinical management. The study highlights the potential of implementing precision medicine in the patients.

scholarly journals Novel MYO15A variants are associated with hearing loss in the two Iranian pedigrees

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Somayeh Khatami ◽  
Masomeh Askari ◽  
Fatemeh Bahreini ◽  
Morteza Hashemzadeh-Chaleshtori ◽  
Saeed Hematian ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Diagnosis ◽  
Clinical Genetic ◽  
Large Size ◽  
Whole Exome ◽  
Novel Variants ◽  
Syndromic Hearing Loss ◽  
Traditional Approaches

Abstract Background Clinical genetic diagnosis of non-syndromic hearing loss (NSHL) is quite challenging. With regard to its high heterogeneity as well as large size of some genes, it is also really difficult to detect causative mutations using traditional approaches. One of the recent technologies called whole-exome sequencing (WES) has been thus developed in this domain to remove the limitations of conventional methods. Methods This study was a report on a research study of two unrelated pedigrees with multiple affected cases of hearing loss (HL). Accordingly, clinical evaluations and genetic analysis were performed in both families. Results The results of WES data analysis to uncover autosomal recessive non-syndromic hearing loss (ARNSHL) disease-causing variants was reported in the present study. Initial analysis identified two novel variants of MYO15A i.e. c.T6442A:p.W2148R and c.10504dupT:p.C3502Lfs*15 correspondingly which were later confirmed by Sanger validations and segregation analyses. According to online prediction tools, both identified variants seemed to have damaging effects. Conclusion In this study, whole exome sequencing were used as a first approach strategy to identify the two novel variants in MYO15A in two Iranian families with ARNSHL.

scholarly journals Genetic Diagnosis Using Whole Exome Sequencing in Common Variable Immunodeficiency

2016 ◽  
Vol 7 ◽  
Author(s):  
Patrick Maffucci ◽  
Charles A. Filion ◽  
Bertrand Boisson ◽  
Yuval Itan ◽  
Lei Shang ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Common Variable Immunodeficiency ◽  
Genetic Diagnosis ◽  
Whole Exome ◽  
Common Variable

scholarly journals Whole-exome sequencing reveals a novel homozygous mutation in the COQ8B gene associated with nephrotic syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohd Fareed ◽  
Vikas Makkar ◽  
Ravi Angral ◽  
Mohammad Afzal ◽  
Gurdarshan Singh
Keyword(s):  
Nephrotic Syndrome ◽  
Disease Management ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Homozygous Mutation ◽  
Consanguineous Family ◽  
Clinical Prognosis ◽  
Whole Exome ◽  
Recurrent Mutations ◽  
Ckd Stage

AbstractNephrotic syndrome arising from monogenic mutations differs substantially from acquired ones in their clinical prognosis, progression, and disease management. Several pathogenic mutations in the COQ8B gene are known to cause nephrotic syndrome. Here, we used the whole-exome sequencing (WES) technology to decipher the genetic cause of nephrotic syndrome (CKD stage-V) in a large affected consanguineous family. Our study exposed a novel missense homozygous mutation NC_000019.9:g.41209497C > T; NM_024876.4:c.748G > A; NP_079152.3:p.(Asp250Asn) in the 9th exon of the COQ8B gene, co-segregated well with the disease phenotype. Our study provides the first insight into this homozygous condition, which has not been previously reported in 1000Genome, ClinVar, ExAC, and genomAD databases. In addition to the pathogenic COQ8B variant, the WES data also revealed some novel and recurrent mutations in the GLA, NUP107, COQ2, COQ6, COQ7 and COQ9 genes. The novel variants observed in this study have been submitted to the ClinVar database and are publicly available online with the accessions: SCV001451361.1, SCV001451725.1 and SCV001451724.1. Based on the patient's clinical history and genomic data with in silico validation, we conclude that pathogenic mutation in the COQ8B gene was causing kidney failure in an autosomal recessive manner. We recommend WES technology for genetic testing in such a consanguineous family to not only prevent the future generation, but early detection can help in disease management and therapeutic interventions.

P–541 Identification of novel variants and candidate genes in women with familial idiopathic premature ovarian failure using whole-exome sequencing

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
R Morale. Sabater ◽  
B Lledo ◽  
J A Ortiz ◽  
F Lozano ◽  
A Bernabeu ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Candidate Genes ◽  
Allele Frequency ◽  
Whole Exome Sequencing ◽  
Minor Allele Frequency ◽  
Premature Ovarian Failure ◽  
Ovarian Function ◽  
Ovarian Failure ◽  
Minor Allele ◽  
Whole Exome

Abstract Study question Is it possible to identify a genetic cause of familial premature ovarian failure (POF) with whole-exome sequencing (WES)? Summary answer Whole-exome sequencing is the most efficient strategy to identify probably pathogenic mutations in different genes in pathologies of polygenic etiology such as premature ovarian failure. What is known already Premature ovarian failure is the loss of ovarian function before the age of 40, and it is a common cause of infertility in women. This pathology has a heterogeneous etiology. Some chromosomal and genetic alterations have been described, and could explain approximately 20% of cases. However, in most patients the origin remains unknown. Recent studies with next-generation sequencing (NGS) have identified new variants in candidate genes related with premature ovarian insufficiency (POI) or premature ovarian failure (POF). These genes are not only involved in processes such as folliculogenesis, but also with DNA damage repair, homologous recombination, and meiosis. Study design, size, duration Fourteen women, from 7 families, affected by idiopathic POF were included in the study from October 2019 to September 2020. Seven POF patients were recruited when they came to our clinic to undergo assisted reproductive treatment. In the anamnesis, it was found that they had relatives with a diagnosis of POF, who were also recruited for the study. The inclusion criteria were amenorrhea before 38 years old and analytical and ultrasound signs of ovarian failure. Participants/materials, setting, methods WES was performed using TrusightOne (Illumina®). Sequenced data were aligned through BWA tool and GATK algorithm was used for SNVs/InDel identification. VCF files were annotated using Variant Interpreter software. Only the variants shared by each family were extracted for analysis and these criteria were followed: (1) Exonic/splicing variants in genes related with POF or involved in biological ovarian functions (2) Variants with minor allele frequency (MAF) ≤0.05 and (3) having potentially moderate/strong functional effects. Main results and the role of chance Seventy-nine variants possibly related with the POF phenotype were identified in the seven families. All these variants had a minor allele frequency (MAF) ≤0.05 in the gnomAD database and 1000 genomes project. Among these candidate variants, two were nonsense, six splice region, one frameshift, two inframe deletion and 68 missense. Thirty-two of the missense variants were predicted to have deleterious effects by minimum two of the four in silico algorithms used (SIFT, PolyPhen–2, MutationTaster and PROVEAN). All variants were heterozygous, and all the families carried three or more candidate variants. Altogether, 43 probably damaging genetic variants were identified in 39 genes expressed in the ovary and related with POF/POI or linked to ovarian physiology. We have described genes that have never been associated to POF pathology, however they may be involved in key biological processes for ovarian function. Moreover, some of these genes were found in two families, for example DDX11, VWF, PIWIL3 and HSD3B1. DDX11 may function at the interface of replication-coupled DNA repair and sister chromatid cohesion. VWF gene is suggested to be associated with follicular atresia in previous studies. PIWIL3 functions in development and maintenance of germline stem cells, and HSD3B1 is implicated in ovarian steroidogenesis. Limitations, reasons for caution Whole-exome sequencing has some limitations: does not cover noncoding regions of the genome, it also cannot detect large rearrangements, copy-number variants (large deletions/duplications), mosaic mutations, mutations in repetitive or high GC rich regions and mutations in genes with corresponding pseudogenes or other highly homologous sequences. Wider implications of the findings: WES has previously shown to be an efficient tool to identify genes as cause of POF, and has demonstrated the polygenic etiology. Although some studies have focused on it, and many genes are identified, this study proposes new candidate genes and variants, having potentially moderate/strong functional effects, associated with POF. Trial registration number Not applicable

Identification of Two Novel Mutations in PKHD1 Gene from Two Families with Polycystic Kidney Disease by Whole Exome Sequencing

2021 ◽  
Vol 22 ◽  
Author(s):  
Masoud Heidari ◽  
Hamid Gharshasbi ◽  
Alireza Isazadeh ◽  
Morteza Soleyman-Nejad ◽  
Mohammad Hossein Taskhiri ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Exome Sequencing ◽  
Polycystic Kidney Disease ◽  
Whole Exome Sequencing ◽  
Novel Mutation ◽  
Genetic Diagnosis ◽  
Genetic Alterations ◽  
Polycystic Kidney ◽  
Novel Mutations ◽  
Whole Exome

Background:: Polycystic kidney disease (PKD) is an autosomal recessive disorder resulting from mutations in the PKHD1 gene on chromosome 6 (6p12), a large gene spanning 470 kb of genomic DNA. Objective: The aim of the present study was to report newly identified mutations in the PKHD1 gene in two Iranian families with PKD. Materials and Methods: Genetic alterations of a 3-month-old boy and a 27-year-old girl with PKD were evaluated using whole-exome sequencing. The PCR direct sequencing was performed to analyse the co-segregation of the variants with the disease in the family. Finally, the molecular function of the identified novel mutations was evaluated by in silico study. Results: In the 3 month-old boy, a novel homozygous frameshift mutation was detected in the PKHD1 gene, which can cause PKD. Moreover, we identified three novel heterozygous missense mutations in ATIC, VPS13B, and TP53RK genes. In the 27-year-old woman, with two recurrent abortions history and two infant mortalities at early weeks due to metabolic and/or renal disease, we detected a novel missense mutation on PKHD1 gene and a novel mutation in ETFDH gene. Conclusion: In general, we have identified two novel mutations in the PKHD1 gene. These molecular findings can help accurately correlate genotype and phenotype in families with such disease in order to reduce patient births through preoperative genetic diagnosis or better management of disorders.

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