Identification of Novel Gene Variants in Turkish Families with Non-Syndromic Congenital Cataracts Using Whole-Exome Sequencing

2021 ◽  
Author(s):  
Ayberk Türkyılmaz ◽  
Aysin Tuba Kaplan ◽  
Sibel Öskan Yalçın ◽  
Safiye Güneş Sağer ◽  
Şaban Şimşek
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Molecular Genetic ◽  
Autosomal Recessive Inheritance ◽  
Turkish Population ◽  
Pedigree Analysis ◽  
Study Patient ◽  
Whole Exome ◽  
Novel Variants ◽  
Unknown Significance

Abstract Purpose The present study aimed to identify the molecular etiology of non-syndromic congenital cataract (CC) using whole-exome sequencing (WES) analysis. Methods In the present study, ophthalmologic results and pedigree analysis of the families of 12 patients with non-syndromic CC were evaluated. WES analysis was conducted after DNA was isolated from peripheral blood samples obtained from the patients.Results Twelve non-syndromic probands (10 male and 2 female) with bilateral CC were included in the study. Patient age ranged between 1 and 11 months. WES analysis showed pathogenic/likely pathogenic variant in 7 (58%) of the 12 families and variant of unknown significance (VUS) in 5 (42%) of them. All the 13 different variants detected in 9 different CC-related genes were co-segregated with the disease. Autosomal dominant inheritance was found in 7 (58%) of the families and autosomal recessive inheritance was found in 5 (42%) of them.Conclusion To the best of our knowledge, the present research is one of the limited numbers of studies in the Turkish population in which genetically heterogeneous non-syndromic CC was investigated using WES analysis. Novel variants that we identified in DNMP, LSS, and WFS1 genes, which are rarely associated with the CC phenotype, have contributed to the mutation spectrum of this disease. Identifying the relevant molecular genetic etiology allows accurate genetic counseling to be provided to the families.

Whole‐Exome Sequencing of a Saudi Epilepsy Cohort Reveals Association Signals in Known and Potentially Novel Loci

2021 ◽  
Author(s):  
Amein Kadhem AlAli ◽  
Abdulrahman Al-Enazi ◽  
Ahmed Ammar ◽  
Mahmoud Hajj ◽  
Cyril Cyrus ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Rare Variants ◽  
High Rate ◽  
Variants Of Unknown Significance ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Novel Variants ◽  
Unknown Significance ◽  
Rare Genetic Variants

Abstract Background Epilepsy, a serious chronic neurological condition effecting up to 100 million people globally, has clear genetic underpinnings including common and rare variants. In Saudi Arabia the prevalence of epilepsy is high and caused mainly by perinatal and genetic factors. No whole-exome sequencing (WES) studies have been performed to date in Saudi Arabian Epilepsy cohorts. This offers a unique opportunity for the discovery of rare genetic variants impacting this disease as there is a high rate of consanguinity amongst large tribal pedigrees. Results We performed WES on 144 individuals diagnosed with epilepsy, to interrogate known Epilepsy related genes for known and functional novel variants. We also used an American College of Medical Genetics (ACMG) guideline based variant prioritization approach in an attempt to discover putative causative variants. We identified a 32 potentially causative pathogenic variants across 30 different genes in 44/144 (30%) of these Saudi Epilepsy individuals. We also identified 232 variants of unknown significance (VUS) across 101 different genes in 133/144 (92%) subjects. Strong enrichment of variants of likely pathogenicity were observed in previously described epilepsy-associated loci, and a number of putative pathogenic variants in novel loci are also observed. Conclusion Several putative pathogenic variants known to be epilepsy-related loci were identified for the first time in our population, in addition to several potential new loci have been identified which may be prioritized for further investigation.

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 Whole-Exome Sequencing Identifies Novel Variants for Tooth Agenesis

2017 ◽  
Vol 97 (1) ◽  
pp. 49-59 ◽  
Author(s):  
N. Dinckan ◽  
R. Du ◽  
L.E. Petty ◽  
Z. Coban-Akdemir ◽  
S.N. Jhangiani ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Permanent Teeth ◽  
Tooth Agenesis ◽  
Disease Genes ◽  
Nonsense Mediated Decay ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Novel Variants ◽  
Complex Inheritance

Tooth agenesis is a common craniofacial abnormality in humans and represents failure to develop 1 or more permanent teeth. Tooth agenesis is complex, and variations in about a dozen genes have been reported as contributing to the etiology. Here, we combined whole-exome sequencing, array-based genotyping, and linkage analysis to identify putative pathogenic variants in candidate disease genes for tooth agenesis in 10 multiplex Turkish families. Novel homozygous and heterozygous variants in LRP6, DKK1, LAMA3, and COL17A1 genes, as well as known variants in WNT10A, were identified as likely pathogenic in isolated tooth agenesis. Novel variants in KREMEN1 were identified as likely pathogenic in 2 families with suspected syndromic tooth agenesis. Variants in more than 1 gene were identified segregating with tooth agenesis in 2 families, suggesting oligogenic inheritance. Structural modeling of missense variants suggests deleterious effects to the encoded proteins. Functional analysis of an indel variant (c.3607+3_6del) in LRP6 suggested that the predicted resulting mRNA is subject to nonsense-mediated decay. Our results support a major role for WNT pathways genes in the etiology of tooth agenesis while revealing new candidate genes. Moreover, oligogenic cosegregation was suggestive for complex inheritance and potentially complex gene product interactions during development, contributing to improved understanding of the genetic etiology of familial tooth agenesis.

Whole Exome Sequencing of Six Chinese Families With Hereditary Non-Syndromic Hearing Loss: A Genetic Etiology Study

2020 ◽  
Author(s):  
Pengfei Liang ◽  
Fengping Chen ◽  
Shujuan Wang ◽  
Qiong Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Sanger Sequencing ◽  
Large Scale ◽  
Autosomal Recessive ◽  
Autosomal Recessive Inheritance ◽  
Chinese Families ◽  
Whole Exome ◽  
Syndromic Hearing Loss

Abstract Background: Hereditary non-syndromic hearing loss (NSHL) has a high genetic heterogeneity with >152 genes identified as associated molecular causes. The present study aimed to detect the possible damaging variants of the deaf probands from six unrelated Chinese families.Methods: After excluding the mutations in the most common genes, GJB2 and SLC26A4, 12 probands with prelingual deafness and autosomal recessive inheritance were evaluated by whole-exome sequencing (WES). All the candidate variants were verified by Sanger sequencing in all patients and their parents.Results: Biallelic mutations were identified in all deaf patients. Among these six families, 10 potentially causative mutations, including 3 reported and 7 novel mutations, in 3 different deafness-associated autosomal recessive (DFNB) genes (MYO15A, COL11A2, and CDH23) were identified. The mutations in MYO15A were frequent with 7/10 candidate variants. Sanger sequencing confirmed that these mutations segregated with the hearing loss of each family.Conclusions: Next-generation sequencing (NGS) approach becomes more cost-effective and efficient when analyzing large-scale genes compared to the conventional polymerase chain reaction-based Sanger sequencing, which is often used to screen common deafness-related genes. The current findings further extend the mutation spectrum of hearing loss in the Chinese population, which has a positive significance for genetic counseling.

scholarly journals Proposal for Modification of Cahan's Criteria Utilizing Molecular Genetic Analyses for Cases without Baseline Histopathology: A Unique Method Applicable to Primary Radiosurgery

2018 ◽  
Vol 80 (01) ◽  
pp. 010-017
Author(s):  
Aaron Rusheen ◽  
James Smadbeck ◽  
Lisa Schimmenti ◽  
Eric Klee ◽  
Michael Link ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Vestibular Schwannoma ◽  
Radiation Treatment ◽  
Molecular Genetic ◽  
Secondary Malignancy ◽  
Whole Exome ◽  
Mate Pair ◽  
Generation Sequencing

Background Cahan's criteria have been utilized since 1948 to establish causality between prior radiation treatment and the development of secondary malignancy. One major criterion specifies that histological and radiographic evidence collected before and after radiation treatment must confirm separate tumor types; however, pretreatment biopsy is rarely obtained prior to radiosurgery for vestibular schwannoma and many other skull base and cranial lesions. Therefore, in these cases Cahan's criteria cannot be validly applied. Objective This article proposes an update to Cahan's criteria using modern molecular genetic analysis for cases lacking baseline histopathology. Methods Mate-pair sequencing and whole exome sequencing of a cerebellopontine angle undifferentiated high-grade pleomorphic sarcoma (UHGPS) that developed after stereotactic radiosurgery of a presumed benign vestibular schwannoma. Results Mate-pair sequencing and whole exome sequencing of the sarcoma revealed complex chromosomal aberrations. Notably, the tumor contained a deletion in the NF2 gene at 22q12 and an in-frame deletion on exon 5 of the remaining copy of NF2. Biallelic events impacting NF2 are atypical for UHGPS but are characteristic for vestibular schwannoma. These findings help support the conclusion that the UHGPS arose from a benign vestibular schwannoma all along. Conclusions Next-generation sequencing can be successfully applied to a radiation-induced sarcoma when both the original and malignant tumors harbor separate signature genetic markers. As our understanding of the genetic profile of various tumors expand, we believe that next-generation sequencing and other genomic tools will play an increasingly important role in establishing causality between radiation and the development of secondary malignancy.

DMC1 mutation that causes human non-obstructive azoospermia and premature ovarian insufficiency identified by whole-exome sequencing

2018 ◽  
Vol 55 (3) ◽  
pp. 198-204 ◽  
Author(s):  
Wen-Bin He ◽  
Chao-Feng Tu ◽  
Qiang Liu ◽  
Lan-Lan Meng ◽  
Shi-Min Yuan ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Missense Mutation ◽  
Whole Exome Sequencing ◽  
Male Patient ◽  
Histological Analysis ◽  
Pedigree Analysis ◽  
Obstructive Azoospermia ◽  
Ovarian Insufficiency ◽  
Causative Gene ◽  
Whole Exome

BackgroundThe genetic causes of the majority of male and female infertility caused by human non-obstructive azoospermia (NOA) and premature ovarian insufficiency (POI) with meiotic arrest are unknown.ObjectiveTo identify the genetic cause of NOA and POI in two affected members from a consanguineous Chinese family.MethodsWe performed whole-exome sequencing of DNA from both affected patients. The identified candidate causative gene was further verified by Sanger sequencing for pedigree analysis in this family. In silico analysis was performed to functionally characterise the mutation, and histological analysis was performed using the biopsied testicle sample from the male patient with NOA.ResultsWe identified a novel homozygous missense mutation (NM_007068.3: c.106G>A, p.Asp36Asn) in DMC1, which cosegregated with NOA and POI phenotypes in this family. The identified missense mutation resulted in the substitution of a conserved aspartic residue with asparaginate in the modified H3TH motif of DMC1. This substitution results in protein misfolding. Histological analysis demonstrated a lack of spermatozoa in the male patient’s seminiferous tubules. Immunohistochemistry using a testis biopsy sample from the male patient showed that spermatogenesis was blocked at the zygotene stage during meiotic prophase I.ConclusionsTo the best of our knowledge, this is the first report identifying DMC1 as the causative gene for human NOA and POI. Furthermore, our pedigree analysis shows an autosomal recessive mode of inheritance for NOA and POI caused by DMC1 in this family.

scholarly journals Pathogenic variants identified by whole-exome sequencing in 43 patients with epilepsy

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Linlin Zhang ◽  
Jinshuang Gao ◽  
Hailiang Liu ◽  
Yuan Tian ◽  
Xiaoli Zhang ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Treatment Options ◽  
Molecular Genetic ◽  
Epileptic Encephalopathy ◽  
Molecular Genetic Analysis ◽  
Specific Diagnosis ◽  
Whole Exome ◽  
Early Establishment

Abstract Background Epilepsy is a group of neurological disorders characterized by recurrent epileptic seizures. Epilepsy is affected by many factors, approximately 20–30% of cases are caused by acquired conditions, but in the remaining cases, genetic factors play an important role. Early establishment of a specific diagnosis is important to treat and manage this disease. Methods In this study, we have recruited 43 epileptic encephalopathy patients and the molecular genetic analysis of those children was performed by whole-exome sequencing (WES). Results Fourteen patients (32.6%, 14/43) had positive genetic diagnoses, including fifteen mutations in fourteen genes. The overall diagnostic yield was 32.6%. A total of 9 patients were diagnosed as pathogenic mutations, including 4 variants had been reported as pathogenic previously and 6 novel variants that had not been reported previously. Therefore, WES heralds promise as a tool for clinical diagnosis of patients with genetic disease. Conclusion Early establishment of a specific diagnosis, on the one hand, is necessary for providing an accurate prognosis and recurrence risk as well as optimizing management and treatment options. On the other hand, to unveil the genetic architecture of epilepsy, it is of vital importance to investigate the phenotypic and genetic complexity of epilepsy.

scholarly journals Whole Exome Sequencing Identifies Three Novel Mutations in the ASPM Gene From Saudi Families Leading to Primary Microcephaly

2021 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Imran Naseer ◽  
Angham Abdulrahman Abdulkareem ◽  
Osama Yousef Muthaffar ◽  
Sameera Sogaty ◽  
Hiba Alkhatabi ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Frameshift Mutation ◽  
Genetic Defect ◽  
Deletion Mutation ◽  
Primary Microcephaly ◽  
Novel Mutations ◽  
Whole Exome ◽  
Novel Variants ◽  
Healthy Control

Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental defect that is characterized by reduced head circumference at birth along with non-progressive intellectual disability. Till date, 25 genes related to MCPH have been reported so far in humans. The ASPM (abnormal spindle-like, microcephaly-associated) gene is among the most frequently mutated MCPH gene. We studied three different families having primary microcephaly from different regions of Saudi Arabia. Whole exome sequencing (WES) and Sanger sequencing were done to identify the genetic defect. Collectively, three novel variants were identified in the ASPM gene from three different primary microcephaly families. Family 1, showed a deletion mutation leading to a frameshift mutation c.1003del. (p.Val335*) in exon 3 of the ASPM gene and family 2, also showed deletion mutation leading to frameshift mutation c.1047del (p.Gln349Hisfs*18), while in family 3, we identified a missense mutation c.5623A>G leading to a change in protein (p.Lys1875Glu) in exon 18 of the ASPM gene underlying the disorder. The identified respective mutations were ruled out in 100 healthy control samples. In conclusion, we found three novel mutations in the ASPM gene in Saudi families that will help to establish a disease database for specified mutations in Saudi population and will further help to identify strategies to tackle primary microcephaly in the kingdom.

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