scholarly journals Genetic and Mitochondrial Metabolic Analyses of an Atypical Form of Leigh Syndrome

2021 ◽  
Vol 9 ◽  
Author(s):  
Martine Uittenbogaard ◽  
Kuntal Sen ◽  
Matthew Whitehead ◽  
Christine A. Brantner ◽  
Yue Wang ◽  
...  
Keyword(s):  
Brain Mri ◽  
Leigh Syndrome ◽  
Metabolic Reprogramming ◽  
Energy Deficit ◽  
Molecular Diagnostic ◽  
Mitochondrial Energy Metabolism ◽  
Atypical Form ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Single Voxel

In this study, we aimed to establish the mitochondrial etiology of the proband’s progressive neurodegenerative disease suggestive of an atypical Leigh syndrome, by determining the proband’s pathogenic variants. Brain MRI showed a constellation of multifocal temporally disparate lesions in the cerebral deep gray nuclei, brainstem, cerebellum, spinal cord along with rhombencephalic atrophy, and optic nerve atrophy. Single voxel 1H MRS performed concurrently over the left cerebral deep gray nuclei showed a small lactate peak, increased glutamate and citrate elevation, elevating suspicion of a mitochondrial etiology. Whole exome sequencing revealed three heterozygous nuclear variants mapping in three distinct genes known to cause Leigh syndrome. Our mitochondrial bioenergetic investigations revealed an impaired mitochondrial energy metabolism. The proband’s overall ATP deficit is further intensified by an ineffective metabolic reprogramming between oxidative phosphorylation and glycolysis. The deficient metabolic adaptability and global energy deficit correlate with the proband’s neurological symptoms congruent with an atypical Leigh syndrome. In conclusion, our study provides much needed insights to support the development of molecular diagnostic and therapeutic strategies for atypical Leigh syndrome.

Molecular defects identified by whole exome sequencing in a child with atypical mucopolysaccharidosis IIIB

2017 ◽  
Vol 30 (4) ◽  
Author(s):  
Qingwen Zeng ◽  
Yanjie Fan ◽  
Lili Wang ◽  
Zhuo Huang ◽  
Xuefan Gu ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Novel Mutation ◽  
Unknown Etiology ◽  
Mendelian Disease ◽  
Atypical Form ◽  
Pathogenic Variants ◽  
Diagnostic Potential ◽  
Whole Exome ◽  
Related Enzyme

AbstractBackground:Mucopolysaccharidosis IIIB (MPS IIIB) is a genetic disease characterized by mutations in theCase presentation:Whole exome sequencing (WES) was conducted and the putative pathogenic variants were validated by Sanger sequencing. The activity of MPS IIIB related enzyme in the patient’s blood serum was assayed. A heterozygous, non-synonymous mutation (c.1562C>T, p.P521L) as well as a novel mutation (c.1705C>A, p.Q569K) were found in theConclusions:Our results describe an atypical form of MPS IIIB and illustrate the diagnostic potential of targeted WES in Mendelian disease with unknown etiology. WES could become a powerful tool for molecular diagnosis of MPS IIIB in clinical setting.

scholarly journals Re-analysis of whole-exome sequencing data uncovers novel diagnostic variants and improves molecular diagnostic yields for sudden death and idiopathic diseases

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Elias L. Salfati ◽  
Emily G. Spencer ◽  
Sarah E. Topol ◽  
Evan D. Muse ◽  
Manuel Rueda ◽  
...  
Keyword(s):  
Sudden Death ◽  
Rare Disease ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Molecular Diagnostic ◽  
Sudden Unexplained Death ◽  
Unexplained Death ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background Whole-exome sequencing (WES) has become an efficient diagnostic test for patients with likely monogenic conditions such as rare idiopathic diseases or sudden unexplained death. Yet, many cases remain undiagnosed. Here, we report the added diagnostic yield achieved for 101 WES cases re-analyzed 1 to 7 years after initial analysis. Methods Of the 101 WES cases, 51 were rare idiopathic disease cases and 50 were postmortem “molecular autopsy” cases of early sudden unexplained death. Variants considered for reporting were prioritized and classified into three groups: (1) diagnostic variants, pathogenic and likely pathogenic variants in genes known to cause the phenotype of interest; (2) possibly diagnostic variants, possibly pathogenic variants in genes known to cause the phenotype of interest or pathogenic variants in genes possibly causing the phenotype of interest; and (3) variants of uncertain diagnostic significance, potentially deleterious variants in genes possibly causing the phenotype of interest. Results Initial analysis revealed diagnostic variants in 13 rare disease cases (25.4%) and 5 sudden death cases (10%). Re-analysis resulted in the identification of additional diagnostic variants in 3 rare disease cases (5.9%) and 1 sudden unexplained death case (2%), which increased our molecular diagnostic yield to 31.4% and 12%, respectively. Conclusions The basis of new findings ranged from improvement in variant classification tools, updated genetic databases, and updated clinical phenotypes. Our findings highlight the potential for re-analysis to reveal diagnostic variants in cases that remain undiagnosed after initial WES.

scholarly journals Biallelic DAB1 Variants Are Associated With Mild Lissencephaly and Cerebellar Hypoplasia

2021 ◽  
Vol 7 (2) ◽  
pp. e558
Author(s):  
Daphne J. Smits ◽  
Rachel Schot ◽  
Martina Wilke ◽  
Marjon van Slegtenhorst ◽  
Marie Claire Y. de Wit ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Splice Variants ◽  
Brain Mri ◽  
Cerebellar Vermis ◽  
Compound Heterozygous ◽  
Loss Of Function ◽  
Functional Studies ◽  
Pathogenic Variants ◽  
Whole Exome

ObjectiveWe aimed to identify pathogenic variants in a girl with epilepsy, developmental delay, cerebellar ataxia, oral motor difficulty, and structural brain abnormalities with the use of whole-exome sequencing.MethodsWhole-exome trio analysis and molecular functional studies were performed in addition to the clinical findings and neuroimaging studies.ResultsBrain MRI showed mild pachygyria, hypoplasia of the cerebellar vermis, and abnormal foliation of the cerebellar vermis, suspected for a variant in one of the genes of the Reelin pathway. Trio whole-exome sequencing and additional functional studies were performed to identify the pathogenic variants. Trio whole-exome sequencing revealed compound heterozygous splice variants in DAB1, both affecting the highly conserved functional phosphotyrosine-binding domain. Expression studies in patient-derived cells showed loss of normal transcripts, confirming pathogenicity.ConclusionsWe conclude that these variants are very likely causally related to the cerebral phenotype and propose to consider loss-of-function DAB1 variants in patients with RELN-like cortical malformations.

scholarly journals Whole exome sequencing uncovered highly penetrant recessive mutations for a spectrum of rare genetic pediatric diseases in Bangladesh

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Hosneara Akter ◽  
Mohammad Shahnoor Hossain ◽  
Nushrat Jahan Dity ◽  
Md. Atikur Rahaman ◽  
K. M. Furkan Uddin ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Diseases ◽  
Leigh Syndrome ◽  
Genetic Profile ◽  
Compound Heterozygous ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Rare Genetic Diseases ◽  
Compound Heterozygous Variants

AbstractCollectively, rare genetic diseases affect a significant number of individuals worldwide. In this study, we have conducted whole-exome sequencing (WES) and identified underlying pathogenic or likely pathogenic variants in five children with rare genetic diseases. We present evidence for disease-causing autosomal recessive variants in a range of disease-associated genes such as DHH-associated 46,XY gonadal dysgenesis (GD) or 46,XY sex reversal 7, GNPTAB-associated mucolipidosis II alpha/beta (ML II), BBS1-associated Bardet–Biedl Syndrome (BBS), SURF1-associated Leigh Syndrome (LS) and AP4B1-associated spastic paraplegia-47 (SPG47) in unrelated affected members from Bangladesh. Our analysis pipeline detected three homozygous mutations, including a novel c. 863 G > C (p.Pro288Arg) variant in DHH, and two compound heterozygous variants, including two novel variants: c.2972dupT (p.Met991Ilefs*) in GNPTAB and c.229 G > C (p.Gly77Arg) in SURF1. All mutations were validated by Sanger sequencing. Collectively, this study adds to the genetic heterogeneity of rare genetic diseases and is the first report elucidating the genetic profile of (consanguineous and nonconsanguineous) rare genetic diseases in the Bangladesh population.

Abstract 12059: Incidental Findings in Cardiomyopathy and Channelopathy Genes Among 5891 Individuals Undergoing Whole-exome Sequencing. What Should be Reported?

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Elisa Mastantuono ◽  
Thomas Wieland ◽  
Riccardo Berutti ◽  
Peter Lichtner ◽  
Tim Strom ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Incidental Findings ◽  
Genetic Disorders ◽  
Molecular Diagnostic ◽  
Minor Genes ◽  
Variants Of Unknown Significance ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Unknown Significance

Background: Whole-exome-sequencing (WES) is becoming a common molecular diagnostic test for patients with genetic disorders. However, this technique allows the identification not only of mutations responsible for the disease under investigation, but also of variants potentially causing other diseases, the so called “incidental findings” (IFs). The American College of Medical Genetics and Genomics (ACMG) stated that IFs should be reported based on clinical validity and utility and indicated a list of 56 actionable genes. Among these, nearly half (20/56) are major genes associated with channelopathies and cardiomyopathies. Despite these recommendations, most of the studies so far published, reported also mutations in minor genes among the actionable findings. Methods: WES was performed in 5891 individuals without known channelopathies or cardiomyopathies. Exome data were first filtered based on genotype quality. Subsequently, a frequency filter was applied, considering 1000 Genomes, ExAC and our internal exome database. Variants reported as pathogenic in ClinVar or novel but expected to be pathogenic (nonsense, frameshift and splice) were further investigated, following the ACMG guidelines. Major (20) and minor (73) genes associated with channelopathies and cardiomyopathies were evaluated. Results: We identified 3514 variants in the 93 genes under investigation, after applying the quality and frequency filters. Eight variants were classified as pathogenic and 52 as likely pathogenic and they were detected in around 1% of the individuals. The vast majority (85%) of pathogenic or likely pathogenic variants were located in the 20 actionable genes indicated by ACMG. The inclusion of minor genes increased the number of variants of unknown significance (VUS), from 865 to 3454. Conclusion: Our data support the ACMG recommendations in reporting only IFs identified in the 20 major cardiac actionable genes. Indeed, the inclusion of minor genes is mainly increasing the number of VUS, without significantly impacting the number of pathogenic and likely pathogenic variants. The percentage of individuals with potentially clinical relevant variants in these genes is too high in relation to the disease-prevalence: a cardiologic evaluation is warranted.

scholarly journals Contribution of SLC22A12 on hypouricemia and its clinical significance for screening purposes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Do Hyeon Cha ◽  
Heon Yung Gee ◽  
Raul Cachau ◽  
Jong Mun Choi ◽  
Daeui Park ◽  
...  
Keyword(s):  
Genetic Diagnosis ◽  
Kidney Injury ◽  
Genetic Identification ◽  
Diagnostic Screening ◽  
Renal Hypouricemia ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Causal Variants ◽  
Coding Variants ◽  
Independent Cohort

Abstract Differentiating between inherited renal hypouricemia and transient hypouricemic status is challenging. Here, we aimed to describe the genetic background of hypouricemia patients using whole-exome sequencing (WES) and assess the feasibility for genetic diagnosis using two founder variants in primary screening. We selected all cases (N = 31) with extreme hypouricemia (<1.3 mg/dl) from a Korean urban cohort of 179,381 subjects without underlying conditions. WES and corresponding downstream analyses were performed for the discovery of rare causal variants for hypouricemia. Two known recessive variants within SLC22A12 (p.Trp258*, pArg90His) were identified in 24 out of 31 subjects (77.4%). In an independent cohort, we identified 50 individuals with hypouricemia and genotyped the p.Trp258* and p.Arg90His variants; 47 of the 50 (94%) hypouricemia cases were explained by only two mutations. Four novel coding variants in SLC22A12, p.Asn136Lys, p.Thr225Lys, p.Arg284Gln, and p.Glu429Lys, were additionally identified. In silico studies predict these as pathogenic variants. This is the first study to show the value of genetic diagnostic screening for hypouricemia in the clinical setting. Screening of just two ethnic-specific variants (p.Trp258* and p.Arg90His) identified 87.7% (71/81) of Korean patients with monogenic hypouricemia. Early genetic identification of constitutive hypouricemia may prevent acute kidney injury by avoidance of dehydration and excessive exercise.

scholarly journals Whole-exome sequencing with targeted analysis and epilepsy after acute symptomatic neonatal seizures

2021 ◽  
Author(s):  
Adam L. Numis ◽  
Gilberto da Gente ◽  
Elliott H. Sherr ◽  
Hannah C. Glass
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
List Type ◽  
Sequencing Analysis ◽  
Neonatal Seizures ◽  
Pathogenic Variants ◽  
Targeted Analysis ◽  
Whole Exome ◽  
Epilepsy Gene

Abstract Background The contribution of pathogenic gene variants with development of epilepsy after acute symptomatic neonatal seizures is not known. Methods Case–control study of 20 trios in children with a history of acute symptomatic neonatal seizures: 10 with and 10 without post-neonatal epilepsy. We performed whole-exome sequencing (WES) and identified pathogenic de novo, transmitted, and non-transmitted variants from established and candidate epilepsy association genes and correlated prevalence of these variants with epilepsy outcomes. We performed a sensitivity analysis with genes associated with coronary artery disease (CAD). We analyzed variants throughout the exome to evaluate for differential enrichment of functional properties using exploratory KEGG searches. Results Querying 200 established and candidate epilepsy genes, pathogenic variants were identified in 5 children with post-neonatal epilepsy yet in only 1 child without subsequent epilepsy. There was no difference in the number of trios with non-transmitted pathogenic variants in epilepsy or CAD genes. An exploratory KEGG analysis demonstrated a relative enrichment in cell death pathways in children without subsequent epilepsy. Conclusions In this pilot study, children with epilepsy after acute symptomatic neonatal seizures had a higher prevalence of coding variants with a targeted epilepsy gene sequencing analysis compared to those patients without subsequent epilepsy. Impact We performed whole-exome sequencing (WES) in 20 trios, including 10 children with epilepsy and 10 without epilepsy, both after acute symptomatic neonatal seizures. Children with post-neonatal epilepsy had a higher burden of pathogenic variants in epilepsy-associated genes compared to those without post-neonatal epilepsy. Future studies evaluating this association may lead to a better understanding of the risk of epilepsy after acute symptomatic neonatal seizures and elucidate molecular pathways that are dysregulated after brain injury and implicated in epileptogenesis.

scholarly journals Exosomes from Plasma of Neuroblastoma Patients Contain Doublestranded DNA Reflecting the Mutational Status of Parental Tumor Cells

2021 ◽  
Vol 22 (7) ◽  
pp. 3667
Author(s):  
Chiara Degli Esposti ◽  
Barbara Iadarola ◽  
Simone Maestri ◽  
Cristina Beltrami ◽  
Denise Lavezzari ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Acquired Resistance ◽  
Membrane Vesicles ◽  
Preschool Age ◽  
Molecular Diagnostic ◽  
Non Invasive ◽  
Mutational Status ◽  
Whole Exome ◽  
Parental Tumor ◽  
Intercellular Communications

Neuroblastoma (NB) is an aggressive infancy tumor, leading cause of death among preschool age diseases. Here we focused on characterization of exosomal DNA (exo-DNA) isolated from plasma cell-derived exosomes of neuroblastoma patients, and its potential use for detection of somatic mutations present in the parental tumor cells. Exosomes are small extracellular membrane vesicles secreted by most cells, playing an important role in intercellular communications. Using an enzymatic method, we provided evidence for the presence of double-stranded DNA in the NB exosomes. Moreover, by whole exome sequencing, we demonstrated that NB exo-DNA represents the entire exome and that it carries tumor-specific genetic mutations, including those occurring on known oncogenes and tumor suppressor genes in neuroblastoma (ALK, CHD5, SHANK2, PHOX2B, TERT, FGFR1, and BRAF). NB exo-DNA can be useful to identify variants responsible for acquired resistance, such as mutations of ALK, TP53, and RAS/MAPK genes that appear in relapsed patients. The possibility to isolate and to enrich NB derived exosomes from plasma using surface markers, and the quick and easy extraction of exo-DNA, gives this methodology a translational potential in the clinic. Exo-DNA can be an attractive non-invasive biomarker for NB molecular diagnostic, especially when tissue biopsy cannot be easily available.

scholarly journals Genetic Neonatal-Onset Epilepsies and Developmental/Epileptic Encephalopathies with Movement Disorders: A Systematic Review

2021 ◽  
Vol 22 (8) ◽  
pp. 4202
Author(s):  
Carlotta Spagnoli ◽  
Carlo Fusco ◽  
Antonio Percesepe ◽  
Vincenzo Leuzzi ◽  
Francesco Pisani
Keyword(s):  
Movement Disorders ◽  
Time Course ◽  
Neonatal Period ◽  
Age Of Onset ◽  
Brain Mri ◽  
Neonatal Seizure ◽  
Mri Findings ◽  
Epileptic Encephalopathies ◽  
Pathogenic Variants ◽  
Neonatal Onset

Despite expanding next generation sequencing technologies and increasing clinical interest into complex neurologic phenotypes associating epilepsies and developmental/epileptic encephalopathies (DE/EE) with movement disorders (MD), these monogenic conditions have been less extensively investigated in the neonatal period compared to infancy. We reviewed the medical literature in the study period 2000–2020 to report on monogenic conditions characterized by neonatal onset epilepsy and/or DE/EE and development of an MD, and described their electroclinical, genetic and neuroimaging spectra. In accordance with a PRISMA statement, we created a data collection sheet and a protocol specifying inclusion and exclusion criteria. A total of 28 different genes (from 49 papers) leading to neonatal-onset DE/EE with multiple seizure types, mainly featuring tonic and myoclonic, but also focal motor seizures and a hyperkinetic MD in 89% of conditions, with neonatal onset in 22%, were identified. Neonatal seizure semiology, or MD age of onset, were not always available. The rate of hypokinetic MD was low, and was described from the neonatal period only, with WW domain containing oxidoreductase (WWOX) pathogenic variants. The outcome is characterized by high rates of associated neurodevelopmental disorders and microcephaly. Brain MRI findings are either normal or nonspecific in most conditions, but serial imaging can be necessary in order to detect progressive abnormalities. We found high genetic heterogeneity and low numbers of described patients. Neurological phenotypes are complex, reflecting the involvement of genes necessary for early brain development. Future studies should focus on accurate neonatal epileptic phenotyping, and detailed description of semiology and time-course, of the associated MD, especially for the rarest conditions.

scholarly journals The Increasing Impact of Translational Research in the Molecular Diagnostics of Neuromuscular Diseases

2021 ◽  
Vol 22 (8) ◽  
pp. 4274
Author(s):  
Dèlia Yubero ◽  
Daniel Natera-de Benito ◽  
Jordi Pijuan ◽  
Judith Armstrong ◽  
Loreto Martorell ◽  
...  
Keyword(s):  
Molecular Diagnosis ◽  
Clinical Symptoms ◽  
Neuromuscular Diseases ◽  
Genomic Analysis ◽  
Molecular Diagnostic ◽  
Diagnostic Process ◽  
Targeted Analysis ◽  
Whole Exome ◽  
Referral Hospitals ◽  
Uncertain Significance

The diagnosis of neuromuscular diseases (NMDs) has been progressively evolving from the grouping of clinical symptoms and signs towards the molecular definition. Optimal clinical, biochemical, electrophysiological, electrophysiological, and histopathological characterization is very helpful to achieve molecular diagnosis, which is essential for establishing prognosis, treatment and genetic counselling. Currently, the genetic approach includes both the gene-targeted analysis in specific clinically recognizable diseases, as well as genomic analysis based on next-generation sequencing, analyzing either the clinical exome/genome or the whole exome or genome. However, as of today, there are still many patients in whom the causative genetic variant cannot be definitely established and variants of uncertain significance are often found. In this review, we address these drawbacks by incorporating two additional biological omics approaches into the molecular diagnostic process of NMDs. First, functional genomics by introducing experimental cell and molecular biology to analyze and validate the variant for its biological effect in an in-house translational diagnostic program, and second, incorporating a multi-omics approach including RNA-seq, metabolomics, and proteomics in the molecular diagnosis of neuromuscular disease. Both translational diagnostics programs and omics are being implemented as part of the diagnostic process in academic centers and referral hospitals and, therefore, an increase in the proportion of neuromuscular patients with a molecular diagnosis is expected. This improvement in the process and diagnostic performance of patients will allow solving aspects of their health problems in a precise way and will allow them and their families to take a step forward in their lives.

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