Diagnostic yield of panel-based genetic testing in syndromic inherited retinal disease

AbstractThirty percent of all inherited retinal disease (IRD) is accounted for by conditions with extra-ocular features. This study aimed to establish the genetic diagnostic pick-up rate for IRD patients with one or more extra-ocular features undergoing panel-based screening in a clinical setting. One hundred and six participants, tested on a gene panel which contained both isolated and syndromic IRD genes, were retrospectively ascertained from the Manchester Genomic Diagnostics Laboratory database spanning 6 years (2012–2017). Phenotypic features were extracted from the clinical notes and classified according to Human Phenotype Ontology; all identified genetic variants were interpreted in accordance to the American College of Medical Genetics and Genomics guidelines. Overall, 49% (n = 52) of patients received a probable genetic diagnosis. A further 6% (n = 6) had a single disease-associated variant in an autosomal recessive disease-relevant gene. Fifty-two percent (n = 55) of patients had a clinical diagnosis at the time of testing. Of these, 71% (n = 39) received a probable genetic diagnosis. By contrast, for those without a provisional clinical diagnosis (n = 51), only 25% (n = 13) received a probable genetic diagnosis. The clinical diagnosis of Usher (n = 33) and Bardet–Biedl syndrome (n = 10) was confirmed in 67% (n = 22) and 80% (n = 8), respectively. The testing diagnostic rate in patients with clinically diagnosed multisystemic IRD conditions was significantly higher than those without one (71% versus 25%; p value < 0.001). The lower pick-up rate in patients without a clinical diagnosis suggests that panel-based approaches are unlikely to be the most effective means of achieving a molecular diagnosis for this group. Here, we suggest that genome-wide approaches (whole exome or genome) are more appropriate.

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Exome sequencing in paediatric patients with movement disorders

Orphanet Journal of Rare Diseases ◽

10.1186/s13023-021-01688-6 ◽

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.

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NGS and phenotypic ontology-based approaches increase the diagnostic yield in syndromic retinal diseases

Human Genetics ◽

10.1007/s00439-021-02343-7 ◽

2021 ◽

Author(s):

I. Perea-Romero ◽

F. Blanco-Kelly ◽

I. Sanchez-Navarro ◽

I. Lorda-Sanchez ◽

S. Tahsin-Swafiri ◽

...

Keyword(s):

Exome Sequencing ◽

Diagnostic Yield ◽

A Priori ◽

Retinal Diseases ◽

Human Phenotype ◽

Whole Exome ◽

Next Generation Sequencing Ngs ◽

Generation Sequencing ◽

Clinical Category ◽

Selection Of

AbstractSyndromic retinal diseases (SRDs) are a group of complex inherited systemic disorders, with challenging molecular underpinnings and clinical management. Our main goal is to improve clinical and molecular SRDs diagnosis, by applying a structured phenotypic ontology and next-generation sequencing (NGS)-based pipelines. A prospective and retrospective cohort study was performed on 100 probands with an a priori diagnosis of non-Usher SRDs, using available clinical data, including Human Phenotype Ontology annotation, and further classification into seven clinical categories (ciliopathies, specific syndromes and five others). Retrospective molecular diagnosis was assessed using different molecular and bioinformatic methods depending on availability. Subsequently, uncharacterized probands were prospectively screened using other NGS approaches to extend the number of analyzed genes. After phenotypic classification, ciliopathies were the most common SRD (35%). A global characterization rate of 52% was obtained, with six cases incompletely characterized for a gene that partially explained the phenotype. An improved characterization rate was achieved addressing prospective cases (83%) and well-recognizable syndrome (62%) subgroups. The 27% of the fully characterized cases were reclassified into a different clinical category after identification of the disease-causing gene. Clinical-exome sequencing is the most appropriate first-tier approach for prospective cases, whereas whole-exome sequencing and bioinformatic reanalysis increases the diagnosis of uncharacterized retrospective cases to 45%, mostly those with unspecific symptoms. Our study describes a comprehensive approach to SRDs in daily clinical practice and the importance of thorough clinical assessment and selection of the most appropriate molecular test to be used to solve these complex cases and elucidate novel associations.

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Delineation of molecular findings by whole exome sequencing for suspected cases of paediatric-onset mitochondrial diseases in the Southern Chinese population

10.21203/rs.3.rs-23585/v2 ◽

2020 ◽

Author(s):

Mandy Ho-Yin Tsang ◽

Anna Ka-Yee Kwong ◽

Kate Lok-San Chan ◽

Jasmine Lee-Fong Fung ◽

Mullin Ho-Chung Yu ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Chinese Population ◽

Founder Mutation ◽

Diagnostic Yield ◽

Genetic Diagnosis ◽

Mitochondrial Diseases ◽

Chinese Patients ◽

Southern Chinese ◽

Whole Exome

Abstract BackgroundMitochondrial diseases (MDs) are a group of clinically and genetically heterogeneous disorders characterized by defects in oxidative phosphorylation. Since clinical phenotypes of MDs may be non-specific, genetic diagnosis is crucial for guiding disease management. In the current study, whole-exome sequencing (WES) was performed for our paediatric-onset MD cohort of a Southern Chinese origin, with the aim of identifying key disease-causing variants in the Chinese patients with MDs.MethodsWe recruited Chinese patients who had paediatric-onset MDs and a minimum mitochondrial disease criteria (MDC) score of 3. Patients with positive target gene or mitochondrial DNA sequencing results were excluded. WES was performed, variants with population frequency ≤1% were analysed for pathogenicity on the basis of the American College of Medical Genetics and Genomics guidelines.ResultsSixty-six patients with pre-biopsy MDC scores of 3–8 were recruited. The overall diagnostic yield was 35% (23/66). Eleven patients (17%) were found to have mutations in MD-related genes, with COQ4 having the highest mutation rate owing to the Chinese-specific founder mutation (4/66, 6%). Twelve patients (12/66, 18%) had mutations in non-MD-related genes: ATP1A3 (n=3, two were siblings), ALDH5A1 , ARX , FA2H , KCNT1 , LDHD , NEFL , NKX2-2 , TBCK , and WAC.ConclusionsWe confirmed that the COQ4 :c.370G>A, p.(Gly124Ser) variant was a recurrent founder mutation among the Southern Chinese population. Screening for this mutation should therefore be considered while diagnosing Chinese patients suspected to have MDs. Furthermore, WES has proven to be useful in detecting variants in patients suspected to have MDs because it helps to obtain an unbiased and precise genetic diagnosis for these diseases, which are genetically heterogeneous.

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Delineation of molecular findings by whole exome sequencing for suspected cases of paediatric-onset mitochondrial diseases in the Southern Chinese population

10.21203/rs.3.rs-23585/v1 ◽

2020 ◽

Author(s):

Mandy Ho-Yin Tsang ◽

Anna Ka-Yee Kwong ◽

Kate Lok-San Chan ◽

Jasmine Lee-Fong Fung ◽

Mullin Ho-Chung Yu ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Chinese Population ◽

Founder Mutation ◽

Diagnostic Yield ◽

Genetic Diagnosis ◽

Mitochondrial Diseases ◽

Chinese Patients ◽

Southern Chinese ◽

Whole Exome

Abstract Background Mitochondrial diseases (MDs) are a group of clinically and genetically heterogeneous disorders characterized by defects in oxidative phosphorylation. Since clinical phenotypes of MDs may be non-specific, genetic diagnosis is crucial for guiding disease management. In the current study, whole-exome sequencing (WES) was performed for our paediatric-onset MD cohort of a Southern Chinese origin, with the aim of identifying key disease-causing variants in the Chinese patients with MDs.Methods We recruited Chinese patients who had paediatric-onset MDs and a minimum mitochondrial disease criteria (MDC) score of 3. Patients with positive target gene or mitochondrial DNA sequencing results were excluded. WES was performed, variants with population frequency ≤1% were analysed for pathogenicity on the basis of the American College of Medical Genetics and Genomics guidelines.Results Sixty-six patients with pre-biopsy MDC scores of 3–8 were recruited. The overall diagnostic yield was 35% (23/66). Eleven patients (17%) were found to have mutations in MD-related genes, with COQ4 having the highest mutation rate owing to the Chinese-specific founder mutation (4/66, 6%). Twelve patients (12/66, 18%) had mutations in non-MD-related genes: ATP1A3 (n=3, two were siblings), ALDH5A1, ARX, FA2H, KCNT1, LDHD, NEFL, NKX2-2, TBCK, and WAC.Conclusions We confirmed that the COQ4:c.370G>A, p.(Gly124Ser) variant was a recurrent founder mutation among the Southern Chinese population. Screening for this mutation should therefore be considered while diagnosing Chinese patients suspected to have MDs. Furthermore, WES has proven to be useful in detecting variants in patients suspected to have MDs because it helps to obtain an unbiased and precise genetic diagnosis for these diseases, which are genetically heterogeneous.

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Whole Genome Sequencing Increases Molecular Diagnostic Yield Compared with Current Diagnostic Testing for Inherited Retinal Disease

Ophthalmology ◽

10.1016/j.ophtha.2016.01.009 ◽

2016 ◽

Vol 123 (5) ◽

pp. 1143-1150 ◽

Cited By ~ 61

Author(s):

Jamie M. Ellingford ◽

Stephanie Barton ◽

Sanjeev Bhaskar ◽

Simon G. Williams ◽

Panagiotis I. Sergouniotis ◽

...

Keyword(s):

Whole Genome Sequencing ◽

Genome Sequencing ◽

Diagnostic Yield ◽

Diagnostic Testing ◽

Retinal Disease ◽

Molecular Diagnostic ◽

Whole Genome ◽

Inherited Retinal Disease

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Delineation of molecular findings by whole-exome sequencing for suspected cases of paediatric-onset mitochondrial diseases in the Southern Chinese population

Human Genomics ◽

10.1186/s40246-020-00278-0 ◽

2020 ◽

Vol 14 (1) ◽

Author(s):

Mandy H.Y. Tsang ◽

Anna K.Y. Kwong ◽

Kate L.S. Chan ◽

Jasmine L.F. Fung ◽

Mullin H.C. Yu ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Chinese Population ◽

Founder Mutation ◽

Diagnostic Yield ◽

Genetic Diagnosis ◽

Mitochondrial Diseases ◽

Chinese Patients ◽

Southern Chinese ◽

Whole Exome

Abstract Background Mitochondrial diseases (MDs) are a group of clinically and genetically heterogeneous disorders characterized by defects in oxidative phosphorylation. Since clinical phenotypes of MDs may be non-specific, genetic diagnosis is crucial for guiding disease management. In the current study, whole-exome sequencing (WES) was performed for our paediatric-onset MD cohort of a Southern Chinese origin, with the aim of identifying key disease-causing variants in the Chinese patients with MDs. Methods We recruited Chinese patients who had paediatric-onset MDs and a minimum mitochondrial disease criteria (MDC) score of 3. Patients with positive target gene or mitochondrial DNA sequencing results were excluded. WES was performed, variants with population frequency ≤ 1% were analysed for pathogenicity on the basis of the American College of Medical Genetics and Genomics guidelines. Results Sixty-six patients with pre-biopsy MDC scores of 3–8 were recruited. The overall diagnostic yield was 35% (23/66). Eleven patients (17%) were found to have mutations in MD-related genes, with COQ4 having the highest mutation rate owing to the Chinese-specific founder mutation (4/66, 6%). Twelve patients (12/66, 18%) had mutations in non-MD-related genes: ATP1A3 (n = 3, two were siblings), ALDH5A1, ARX, FA2H, KCNT1, LDHD, NEFL, NKX2-2, TBCK, and WAC. Conclusions We confirmed that the COQ4:c.370G>A, p.(Gly124Ser) variant, was a founder mutation among the Southern Chinese population. Screening for this mutation should therefore be considered while diagnosing Chinese patients suspected to have MDs. Furthermore, WES has proven to be useful in detecting variants in patients suspected to have MDs because it helps to obtain an unbiased and precise genetic diagnosis for these diseases, which are genetically heterogeneous.

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The Role of RNA-Sequencing as a New Genetic Diagnosis Tool

Current Genetic Medicine Reports ◽

10.1007/s40142-021-00199-x ◽

2021 ◽

Vol 9 (2) ◽

pp. 13-21

Author(s):

Philippa D. K. Curry ◽

Krystyna L. Broda ◽

Christopher J. Carroll

Keyword(s):

Rna Sequencing ◽

Rare Diseases ◽

Diagnostic Yield ◽

Neuromuscular Disorders ◽

Genetic Diagnosis ◽

Rna Seq ◽

Novel Approach ◽

Whole Exome ◽

Diagnosis Tool

Abstract Purpose of Review Whole exome sequencing (WES) and whole-genome sequencing (WGS) are frontline approaches for the genetic diagnosis of rare diseases. However, WES/WGS fails in up to 75% of cases. Transcriptomics via RNA-sequencing (RNA-Seq) is a novel approach that aims to increase the diagnostic yield in rare diseases. Recent Findings Recent publications focus on the success of RNA-Seq for increasing diagnosis rates in WES/WGS-negative patients in up to 36% of cases, across a range of different diseases, sample sizes, and tissue types. Summary RNA-Seq is beneficial for aiding prioritisation of causative variants currently not detected or often overlooked by WES/WGS alone. An improvement in diagnostic yields has been demonstrated using multiple source tissues, with muscle and fibroblasts being the most representative, but the more accessible blood still demonstrating diagnostic success, particularly in neuromuscular disorders. The introduction of RNA-Seq to the genetic diagnosis toolbox promises to be a useful complementary tool to WES/WGS for improving genetic diagnosis in patients with rare disease.

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Exome Sequencing in Paediatric Patients with Movement Disorders with Treatment Possibilities

10.21203/rs.3.rs-101211/v1 ◽

2020 ◽

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 ◽

Paediatric Patients ◽

Whole Exome ◽

Prediction Of Prognosis

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 targeted 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. Conclusion: 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 using targeted therapies. The study highlights the potential of implementing precision medicine in the patients.

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Abstract 11800: Whole Exome Sequencing in a Large Pedigree With DCM Identifies a Novel Mutation in RBM20

Circulation ◽

10.1161/circ.132.suppl_3.11800 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Tomas Robyns ◽

Johan Van Cleemput ◽

Rik Willems ◽

Shalini Jhangiani ◽

Donna Muzny ◽

...

Keyword(s):

Dilated Cardiomyopathy ◽

Exome Sequencing ◽

Whole Exome Sequencing ◽

Scoring System ◽

Diagnostic Yield ◽

Novel Mutation ◽

Genetic Diagnosis ◽

Single Nucleotide Variants ◽

Large Pedigree ◽

Whole Exome

Background and hypothesis: Familial dilated cardiomyopathy (DCM) is genetically heterogeneous and is associated with mutations in at least 30 different genes. None of these genes have an expected diagnostic yield of more than 10% complicating genetic diagnosis. Whole exome sequencing (WES) is a powerful alternative for the identification of the causal gene, however variant interpretation remains challenging. We performed WES in a large family with autosomal dominant DCM complicated by end stage heart failure and ventricular arrhythmias. The index of this family was evaluated previously by means of targeted gene panel analysis including 28 genes, but no causal mutation was found. Methods and results: WES was applied on 2 affected cousins. First, shared heterozygous variants (single nucleotide variants, small insertions and deletions) located inside the exon or at the exon/intron boundary were selected. Synonymous variants were excluded, except if they were located at the exon/intron boundaries. Variants with a minor allele frequency of >0.1% in publically available exome databases (1000 Genomes and ESP) were excluded. Furthermore, variants that were present in an in-house exome cohort performed for other disease entities were also excluded since these probably represent local SNV’s. The remaining 19 variants were evaluated using a comprehensive scoring system that includes different in-silico analysis tools, orthologous and paralogous conservation and population frequencies. Subsequently Sanger sequencing was performed for 10 variants that were classified as likely pathogenic (N=1) or variants of unknown significance (N=9) according to the scoring system in order to confirm the presence of the variant and to evaluate co-segregation. Only one variant in exon 9 of the RBM20 gene (c.2714T>A, p.Met950Lys, NM_001334363) showed full co-segregation in the 7 affected family members resulting in a maximum 2-point LOD score of 2.1 and suggesting this as the pathogenic mutation responsible for the phenotype. Recently mutations in RBM20 have been linked to dilated cardiomyopathy caused by defective splicing of the giant sarcomeric protein titin. Conclusions: We report the identification of a novel mutation in RBM20 by WES in a large pedigree with DCM.

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Whole-Exome Sequencing Enables a Precision Medicine Approach for Kidney Transplant Recipients

Journal of the American Society of Nephrology ◽

10.1681/asn.2018060575 ◽

2019 ◽

Vol 30 (2) ◽

pp. 201-215 ◽

Cited By ~ 27

Author(s):

Nina Mann ◽

Daniela A. Braun ◽

Kassaundra Amann ◽

Weizhen Tan ◽

Shirlee Shril ◽

...

Keyword(s):

Diagnostic Yield ◽

Molecular Genetic ◽

Genetic Diagnosis ◽

Renal Transplant Recipients ◽

Transplant Recipients ◽

Kidney Transplant Recipients ◽

Whole Exome ◽

Pediatric Renal Transplant ◽

Molecular Genetic Diagnosis ◽

Pediatric Renal Transplant Recipients

BackgroundWhole-exome sequencing (WES) finds a CKD-related mutation in approximately 20% of patients presenting with CKD before 25 years of age. Although provision of a molecular diagnosis could have important implications for clinical management, evidence is lacking on the diagnostic yield and clinical utility of WES for pediatric renal transplant recipients.MethodsTo determine the diagnostic yield of WES in pediatric kidney transplant recipients, we recruited 104 patients who had received a transplant at Boston Children’s Hospital from 2007 through 2017, performed WES, and analyzed results for likely deleterious variants in approximately 400 genes known to cause CKD.ResultsBy WES, we identified a genetic cause of CKD in 34 out of 104 (32.7%) transplant recipients. The likelihood of detecting a molecular genetic diagnosis was highest for patients with urinary stone disease (three out of three individuals), followed by renal cystic ciliopathies (seven out of nine individuals), steroid-resistant nephrotic syndrome (nine out of 21 individuals), congenital anomalies of the kidney and urinary tract (ten out of 55 individuals), and chronic glomerulonephritis (one out of seven individuals). WES also yielded a molecular diagnosis for four out of nine individuals with ESRD of unknown etiology. The WES-related molecular genetic diagnosis had implications for clinical care for five patients.ConclusionsNearly one third of pediatric renal transplant recipients had a genetic cause of their kidney disease identified by WES. Knowledge of this genetic information can help guide management of both transplant patients and potential living related donors.

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