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

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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Analysis of Genotype-Phenotype Correlations in Patients With Degenerative Dementia Through the Whole Exome Sequencing

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.745407 ◽

2021 ◽

Vol 13 ◽

Author(s):

Lin Sun ◽

Jianye Zhang ◽

Ning Su ◽

Shaowei Zhang ◽

Feng Yan ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Clinical Symptoms ◽

Pathogenic Variants ◽

Dementia Patients ◽

Whole Exome ◽

Uncertain Significance ◽

Genetic Features ◽

Standards And Guidelines ◽

Degenerative Dementia

Background: Sporadic dementias generally occur in older age and are highly polygenic, which indicates some patients transmitted in a poly-genes hereditary fashion.Objective: Our study aimed to analyze the correlations of genetic features with clinical symptoms in patients with degenerative dementia.Methods: We recruited a group of 84 dementia patients and conducted the whole exome sequencing (WES). The data were analyzed focusing on 153 dementia-related causing and susceptible genes.Results: According to the American College of Medical Genetics and Genomics (ACMG) standards and guidelines, we identified four reported pathogenic variants, namely, PSEN1 c.A344G, APP c.G2149A, MAPT c.G1165A, and MAPT c.G742A, one reported likely pathogenic variant, namely, PSEN2 c.G100A, one novel pathogenic variants, SQSTM1 c.C671A, and three novel likely pathogenic variants, namely, ABCA7 c.C4690T, ATP13A2 c.3135delC, and NOS3 c.2897-2A > G. 21 variants with uncertain significance in PSEN2, C9orf72, NOTCH3, ABCA7, ERBB4, GRN, MPO, SETX, SORL1, NEFH, ADCM10, and SORL1, etc., were also detected in patients with Alzheimer’s disease (AD) and frontotemporal dementia (FTD).Conclusion: The new variants in dementia-related genes indicated heterogeneity in pathogenesis and phenotype of degenerative dementia. WES could serve as an efficient diagnostic tool for detecting intractable dementia.

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Diagnosis of Genetic White Matter Disorders by Singleton Whole-Exome and Genome Sequencing Using Interactome-Driven Prioritization

Neurology ◽

10.1212/wnl.0000000000013278 ◽

2022 ◽

pp. 10.1212/WNL.0000000000013278

Author(s):

Agatha Schlüter ◽

Agustí Rodríguez-Palmero ◽

Edgard Verdura ◽

Valentina Vélez-Santamaría ◽

Montserrat Ruiz ◽

...

Keyword(s):

White Matter ◽

Candidate Genes ◽

Genome Sequencing ◽

Molecular Diagnosis ◽

Diagnostic Yield ◽

Collaborative Study ◽

Case Series ◽

Genomic Analysis ◽

White Matter Disorders ◽

Whole Exome

Background and Objectives:Genetic white matter disorders (GWMD) are of heterogeneous origin, with more than a hundred causal genes identified to date. Classical targeted approaches achieve a molecular diagnosis in only half of all patients. Here we aim to determine the clinical utility of singleton whole-exome sequencing and whole-genome sequencing (sWES-WGS) interpreted with a phenotype- and interactome-driven prioritization algorithm to diagnose GWMD patients, while identifying novel phenotypes and candidate genes.Methods:A case series of patients of all ages with undiagnosed GWMD despite extensive standard-of-care paraclinical studies were recruited between April 2017 and December 2019 in a collaborative study at the Bellvitge Biomedical Research Institute (IDIBELL) and neurology units of tertiary Spanish hospitals. We ran sWES and WGS and applied our interactome-prioritization algorithm, based on the network expansion of a seed group of GWMD-related genes, derived from the HPO terms of each patient.Results:We received 126 patients (101 children and 25 adults), with ages ranging from 1 month to 74 years. We obtained a first molecular diagnosis by singleton WES in 59% of cases, which increased to 68% after annual reanalysis and reached 72% after WGS was performed in 16 of the remaining negative cases. We identified variants in 57 different genes among 91 diagnosed cases, with the most frequent being RNASEH2B, EIF2B5, POLR3A and PLP1; and a dual diagnosis underlying complex phenotypes in six families, underscoring the importance of genomic analysis to solve these cases. Finally, we discovered 9 candidate genes causing novel diseases, and propose additional putative novel candidate genes for yet-to-be discovered GWMD.Discussion:Our strategy enables a high diagnostic yield and is a good alternative to trio WES/WGS for GWMD. It shortens the time to diagnosis compared to the classical targeted approach, thus optimizing appropriate management. Furthermore, the interactome-driven prioritization pipeline enables the discovery of novel disease-causing genes and phenotypes, and predicts novel putative candidate genes, shedding light on etiopathogenic mechanisms that are pivotal for myelin generation and maintenance.

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

Pediatric Research ◽

10.1038/s41390-021-01509-3 ◽

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.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22073667 ◽

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.

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Novel MSX1 variants identified in families with nonsyndromic oligodontia

International Journal of Oral Science ◽

10.1038/s41368-020-00106-0 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jinglei Zheng ◽

Miao Yu ◽

Haochen Liu ◽

Tao Cai ◽

Hailan Feng ◽

...

Keyword(s):

Current Data ◽

Phenotypic Characterization ◽

Functional Evaluation ◽

Gene Variants ◽

Chinese Families ◽

Whole Exome ◽

Bioinformatics Databases ◽

Uncertain Significance ◽

Vitro Analysis

AbstractThe goal of this study was to identify MSX1 gene variants in multiple Chinese families with nonsyndromic oligodontia and analyse the functional influence of these variants. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify the causal gene variants in five families with nonsyndromic oligodontia, and a series of bioinformatics databases were used for variant confirmation and functional prediction. Phenotypic characterization of the members of these families was described, and an in vitro analysis was performed for functional evaluation. Five novel MSX1 heterozygous variants were identified: three missense variants [c.662A>C (p.Q221P), c.670C>T (p.R224C), and c.809C>T (p.S270L)], one nonsense variant [c.364G>T (p.G122*)], and one frameshift variant [c.277delG (p.A93Rfs*67)]. Preliminary in vitro studies demonstrated that the subcellular localization of MSX1 was abnormal with the p.Q221P, p.R224C, p.G122*, and p.A93Rfs*67 variants compared to the wild type. Three variants (p.Q221P, p.G122*, and p.A93Rfs*67) were classified as pathogenic or likely pathogenic, while p.S270L and p.R224C were of uncertain significance in the current data. Moreover, we summarized and analysed the MSX1-related tooth agenesis positions and found that the type and variant locus were not related to the severity of tooth loss. Our results expand the variant spectrum of nonsyndromic oligodontia and provide valuable information for genetic counselling.

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Rare Variants in Autophagy and Non-Autophagy Genes in Late-Onset Pompe Disease: Suggestions of Their Disease-Modifying Role in Two Italian Families

International Journal of Molecular Sciences ◽

10.3390/ijms22073625 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3625

Author(s):

Filomena Napolitano ◽

Giorgia Bruno ◽

Chiara Terracciano ◽

Giuseppina Franzese ◽

Nicole Piera Palomba ◽

...

Keyword(s):

Pompe Disease ◽

Rare Variants ◽

Clinical Symptoms ◽

Late Onset ◽

Respiratory Muscles ◽

Autosomal Recessive Disorder ◽

Compound Heterozygous ◽

Enzyme Replacement ◽

Whole Exome ◽

Clinical Pictures

Pompe disease is an autosomal recessive disorder caused by a deficiency in the enzyme acid alpha-glucosidase. The late-onset form of Pompe disease (LOPD) is characterized by a slowly progressing proximal muscle weakness, often involving respiratory muscles. In LOPD, the levels of GAA enzyme activity and the severity of the clinical pictures may be highly variable among individuals, even in those who harbour the same combination of GAA mutations. The result is an unpredictable genotype–phenotype correlation. The purpose of this study was to identify the genetic factors responsible for the progression, severity and drug response in LOPD. We report here on a detailed clinical, morphological and genetic study, including a whole exome sequencing (WES) analysis of 11 adult LOPD siblings belonging to two Italian families carrying compound heterozygous GAA mutations. We disclosed a heterogeneous pattern of myopathic impairment, associated, among others, with cardiac defects, intracranial vessels abnormality, osteoporosis, vitamin D deficiency, obesity and adverse response to enzyme replacement therapy (ERT). We identified deleterious variants in the genes involved in autophagy, immunity and bone metabolism, which contributed to the severity of the clinical symptoms observed in the LOPD patients. This study emphasizes the multisystem nature of LOPD and highlights the polygenic nature of the complex phenotype disclosed in these patients.

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Novel mutation in the TGFBI gene in a Moroccan family with atypical corneal dystrophy: a case report

BMC Medical Genomics ◽

10.1186/s12920-020-00861-3 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Yahya Benbouchta ◽

Imane Cherkaoui Jaouad ◽

Habiba Tazi ◽

Hamza Elorch ◽

Mouna Ouhenach ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Clinical Symptoms ◽

Age Of Onset ◽

Novel Mutation ◽

Corneal Dystrophy ◽

Heterozygous Mutation ◽

Large Variability ◽

Whole Exome ◽

Moroccan Family

Abstract Background Corneal dystrophies (CDs) are a heterogeneous group of bilateral, genetically determined, noninflammatory bilateral corneal diseases that are usually limited to the cornea. CD is characterized by a large variability in the age of onset, evolution and visual impact and the accumulation of insoluble deposits at different depths in the cornea. Clinical symptoms revealed bilateral multiple superficial, epithelial, and stromal anterior granular opacities in different stages of severity among three patients of this family. A total of 99 genes are involved in CDs. The aim of this study was to identify pathogenic variants causing atypical corneal dystrophy in a large Moroccan family and to describe the clinical phenotype with severely different stages of evolution. Case presentation In this study, we report a large Moroccan family with CD. Whole-exome sequencing (WES) was performed in the three affected members who shared a phenotype of corneal dystrophy in different stages of severity. Variant validation and familial segregation were performed by Sanger sequencing in affected sisters and mothers and in two unaffected brothers. Whole-exome sequencing showed a novel heterozygous mutation (c.1772C > A; p.Ser591Tyr) in the TGFBI gene. Clinical examinations demonstrated bilaterally multiple superficial, epithelial and stromal anterior granular opacities in different stages of severity among three patients in this family. Conclusions This report describes a novel mutation in the TGFBI gene found in three family members affected by different phenotypic aspects. This mutation is associated with Thiel-Behnke corneal dystrophy; therefore, it could be considered a novel phenotype genotype correlation, which will help in genetic counselling for this family.

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A point-of-care diagnostic for differentiating Ebola from endemic febrile diseases

Science Translational Medicine ◽

10.1126/scitranslmed.aat0944 ◽

2018 ◽

Vol 10 (471) ◽

pp. eaat0944 ◽

Cited By ~ 19

Author(s):

David Sebba ◽

Alexander G. Lastovich ◽

Melody Kuroda ◽

Eric Fallows ◽

Joshua Johnson ◽

...

Keyword(s):

Ebola Virus ◽

Clinical Symptoms ◽

Point Of Care ◽

Hemorrhagic Fever ◽

Diagnostic Methods ◽

Outbreak Detection ◽

Molecular Diagnostic ◽

Clinical Samples ◽

Live Virus ◽

And Control

Hemorrhagic fever outbreaks such as Ebola are difficult to detect and control because of the lack of low-cost, easily deployable diagnostics and because initial clinical symptoms mimic other endemic diseases such as malaria. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need. Although rapid tests such as lateral flow can be broadly deployed, they are typically not well-suited for differentiating among multiple diseases presenting with similar symptoms. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect and differentiate infection with Ebola virus from other more common febrile diseases. Here, we developed and tested an immunoassay technology that uses surface-enhanced Raman scattering (SERS) tags to simultaneously detect antigens from Ebola, Lassa, and malaria within a single blood sample. Results are provided in <30 min for individual or batched samples. Using 190 clinical samples collected from the 2014 West African Ebola outbreak, along with 163 malaria positives and 233 negative controls, we demonstrated Ebola detection with 90.0% sensitivity and 97.9% specificity and malaria detection with 100.0% sensitivity and 99.6% specificity. These results, along with corresponding live virus and nonhuman primate testing of an Ebola, Lassa, and malaria 3-plex assay, indicate the potential of the SERS technology as an important tool for outbreak detection and clinical triage in low-resource settings.

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Not Only Diagnostic Yield: Whole-Exome Sequencing in Infantile Cardiomyopathies Impacts on Clinical and Family Management

Journal of Cardiovascular Development and Disease ◽

10.3390/jcdd9010002 ◽

2021 ◽

Vol 9 (1) ◽

pp. 2

Author(s):

Laura Pezzoli ◽

Lidia Pezzani ◽

Ezio Bonanomi ◽

Chiara Marrone ◽

Agnese Scatigno ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Molecular Diagnosis ◽

Clinical Management ◽

Genetic Diagnosis ◽

Family Management ◽

Whole Exome ◽

Time To Diagnosis ◽

The Mean ◽

Mean Time

Whole-exome sequencing (WES) is a powerful and comprehensive tool for the genetic diagnosis of rare diseases, but few reports describe its timely application and clinical impact on infantile cardiomyopathies (CM). We conducted a retrospective analysis of patients with infantile CMs who had trio (proband and parents)-WES to determine whether results contributed to clinical management in urgent and non-urgent settings. Twenty-nine out of 42 enrolled patients (69.0%) received a definitive molecular diagnosis. The mean time-to-diagnosis was 9.7 days in urgent settings, and 17 out of 24 patients (70.8%) obtained an etiological classification. In non-urgent settings, the mean time-to-diagnosis was 225 days, and 12 out of 18 patients (66.7%) had a molecular diagnosis. In 37 out of 42 patients (88.1%), the genetic findings contributed to clinical management, including heart transplantation, palliative care, or medical treatment, independent of the patient’s critical condition. All 29 patients and families with a definitive diagnosis received specific counseling about recurrence risk, and in seven (24.1%) cases, the result facilitated diagnosis in parents or siblings. In conclusion, genetic diagnosis significantly contributes to patients’ clinical and family management, and trio-WES should be performed promptly to be an essential part of care in infantile cardiomyopathy, maximizing its clinical utility.

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A de novo variant in CASK gene causing intellectual disability and brain hypoplasia: A Case Report and Literature Review

10.21203/rs.3.rs-317232/v1 ◽

2021 ◽

Author(s):

Ying Zhang ◽

Yanyan Nie ◽

Yu Mu ◽

Jie Zheng ◽

Xiaowei Xu ◽

...

Keyword(s):

Intellectual Disability ◽

Mental Disorders ◽

De Novo ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

De Novo Mutation ◽

Loss Of Function ◽

Bioinformatics Analyses ◽

Whole Exome ◽

De Novo Variant

Abstract Background：The pathogenic variation of CASK gene can cause CASK related mental disorders. The main clinical manifestations are microcephaly with pontine and cerebellar hypoplasia, X-linked mental disorders with or without nystagmus and FG syndrome. The main pathogenic mechanism is the loss of function of related protein caused by mutation. We reported a Chinese male newborn with a de novo variant in CASK gene. Case presentation：We present an 18-day-old baby with intellectual disability and brain hypoplasia. Whole-exome sequencing was performed, which detected a hemizygous missense mutation c.764G>A of CASK gene. The mutation changed the 255th amino acid from Arg to His. Software based bioinformatics analyses were conducted to infer its functional effect.Conclusions：In this paper, a de novo mutation of CASK gene was reported. Moreover, a detailed description of all the cases described in the literature is reported.CASK mutations cause a variety of clinical phenotypes. Its diagnosis is difficult due to the lack of typical clinical symptoms. Genetic testing should be performed as early as possible if this disease is suspected. This case provides an important reference for the diagnosis and treatment of future cases.

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