Diagnostic and Clinical Utility of Clinical Exome Sequencing in Children With Moderate and Severe Global Developmental Delay / Intellectual Disability

2019 ◽  
Vol 35 (2) ◽  
pp. 116-131 ◽  
Author(s):  
Jelena Ruml Stojanovic ◽  
Aleksandra Miletic ◽  
Borut Peterlin ◽  
Ales Maver ◽  
Marija Mijovic ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Clinical Utility ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
Significant Proportion ◽  
Global Developmental Delay ◽  
Clinical Exome Sequencing ◽  
The Impact

Clinical exome sequencing is currently being used in diagnostics of various genetic disorders, but studies supporting its application in clinical setting are scarce. The aim of this study was to establish diagnostic and clinical utility of clinical exome sequencing in patients with moderate and severe global developmental delay/intellectual disability. Clinical diagnosis was made in 49 of 88 investigated patients, with overall diagnostic yield of 55.7%. Molecular findings are characterized in detail, including the impact of newly made diagnosis on clinical management. Several previously unreported genotype-phenotype correlations and 33 novel variants are described. Genetic and clinical data were shared through publicly available database. In conclusion, clinical exome sequencing allows identification of causative variants in a significant proportion of patients in investigated clinical subgroup. Compared to whole exome sequencing, it shows similar diagnostic and clinical utility with reduced costs, which could be of particular importance for institutions with limited resources.

scholarly journals Genome sequencing demonstrates high diagnostic yield in children with undiagnosed global developmental delay/intellectual disability: a prospective study

2021 ◽  
Author(s):  
Yu Sun ◽  
Jing Peng ◽  
Desheng Liang ◽  
Xiantao Ye ◽  
Na Xu ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
Genome Sequencing ◽  
Clinical Utility ◽  
Diagnostic Yield ◽  
Chromosomal Microarray ◽  
Global Developmental Delay ◽  
Chromosomal Microarray Analysis ◽  
High Diagnostic Yield ◽  
Wide Range

Genome sequencing(GS) has been applied in the diagnosis of global developmental delay(GDD)/intellectual disability(ID). However, the performance in those with inconclusive results from chromosomal microarray analysis(CMA) and exome sequencing(ES) is unknown. We recruited 100 pediatric GDD/ID patients from multiple sites in China from February 2018 to August 2020 for GS. Patients have received at least one genomic diagnostic test prior to enrollment. Reanalysis of CMA/ES data was performed. The yield of GS was calculated and explanations for missed diagnoses by CMA/ES were investigated. Clinical utility was assessed by interviewing the parents by phone. The overall diagnostic yield of GS was 23%. Seven families could have been solved with reanalysis of ES data. 13 families were missed by previous CMA/ES due to improper method. Three remained unsolved after ES reanalysis due to allele dropout, complex variants missed by ES, and a CNV in untranslated regions. Follow-up of the diagnosed families revealed that nine families experienced changes in clinical management, including identification of targeted treatments, cessation of unnecessary treatment, and considerations for family planning. GS demonstrated high diagnostic yield and clinical utility in this cohort of undiagnosed GDD/ID patients, detecting a wide range of variant types of different sizes in a single workflow.

scholarly journals NAA10 p.(N101K) disrupts N-terminal acetyltransferase complex NatA and is associated with developmental delay and hemihypertrophy

2020 ◽  
Author(s):  
Nina McTiernan ◽  
◽  
Harinder Gill ◽  
Carlos E. Prada ◽  
Harry Pachajoa ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
Genetic Disorders ◽  
Cellular Functions ◽  
Functional Studies ◽  
Phenotypic Spectrum ◽  
Independent Functions ◽  
Evolutionarily Conserved ◽  
Human Proteins ◽  
The Impact

Abstract Nearly half of all human proteins are acetylated at their N-termini by the NatA N-terminal acetyltransferase complex. NAA10 is evolutionarily conserved as the catalytic subunit of NatA in complex with NAA15, but may also have NatA-independent functions. Several NAA10 variants are associated with genetic disorders. The phenotypic spectrum includes developmental delay, intellectual disability, and cardiac abnormalities. Here, we have identified the previously undescribed NAA10 c.303C>A and c.303C>G p.(N101K) variants in two unrelated girls. These girls have developmental delay, but they both also display hemihypertrophy a feature normally not observed or registered among these cases. Functional studies revealed that NAA10 p.(N101K) is completely impaired in its ability to bind NAA15 and to form an enzymatically active NatA complex. In contrast, the integrity of NAA10 p.(N101K) as a monomeric acetyltransferase is intact. Thus, this NAA10 variant may represent the best example of the impact of NatA mediated N-terminal acetylation, isolated from other potential NAA10-mediated cellular functions and may provide important insights into the phenotypes observed in individuals expressing pathogenic NAA10 variants.

scholarly journals Genetic testing in patients with global developmental delay/intellectual disabilities. A review

2015 ◽  
Vol 88 (3) ◽  
pp. 288-292 ◽  
Author(s):  
Diana Miclea ◽  
Loredana Peca ◽  
Zina Cuzmici ◽  
Ioan Victor Pop
Keyword(s):  
Intellectual Disability ◽  
Genetic Testing ◽  
Developmental Disabilities ◽  
Developmental Delay ◽  
Chromosomal Abnormalities ◽  
Fragile X ◽  
Genetic Disorders ◽  
Global Developmental Delay ◽  
European Guidelines ◽  
High Prevalence

Genetic factors are responsible for up to 40 % developmental disability cases, such as global developmental delay/ intellectual disability (GDD/DI). The American and more recently, the European guidelines on this group of diseases state that genetic testing is essential and should become a standardized diagnostic practice. The main arguments for the necessity of implementing such a practice are: (1) the high prevalence of developmental disabilities (3% of the population); (2) the high genetic contribution to this type of pathology; (3) insufficient referral for genetic consultation. In an attempt to address these issues, the purpose of this paper is to present the genetic etiology of global developmental delay / intellectual disability with emphasis on the need to implement a genetic testing protocol for the patients with GDD/DI, as indicated by the current guidelines. Chromosomal abnormalities and fragile X syndrome are the most frequent causes of developmental disabilities and the techniques employed to detect such genetic disorders should be used as first line investigations of GDD/DI. 

scholarly journals Comparison of the diagnostic yield of aCGH and genome-wide sequencing across different neurodevelopmental disorders

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Francisco Martinez-Granero ◽  
Fiona Blanco-Kelly ◽  
Carolina Sanchez-Jimeno ◽  
Almudena Avila-Fernandez ◽  
Ana Arteche ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Neurodevelopmental Disorders ◽  
Diagnostic Yield ◽  
Genetic Diagnosis ◽  
Diagnostic Algorithm ◽  
Signs And Symptoms ◽  
Autism Spectrum ◽  
Global Developmental Delay ◽  
Comparative Genomic ◽  
Clinical Exome Sequencing

AbstractMost consensus recommendations for the genetic diagnosis of neurodevelopmental disorders (NDDs) do not include the use of next generation sequencing (NGS) and are still based on chromosomal microarrays, such as comparative genomic hybridization array (aCGH). This study compares the diagnostic yield obtained by aCGH and clinical exome sequencing in NDD globally and its spectrum of disorders. To that end, 1412 patients clinically diagnosed with NDDs and studied with aCGH were classified into phenotype categories: global developmental delay/intellectual disability (GDD/ID); autism spectrum disorder (ASD); and other NDDs. These categories were further subclassified based on the most frequent accompanying signs and symptoms into isolated forms, forms with epilepsy; forms with micro/macrocephaly and syndromic forms. Two hundred and forty-five patients of the 1412 were subjected to clinical exome sequencing. Diagnostic yield of aCGH and clinical exome sequencing, expressed as the number of solved cases, was compared for each phenotype category and subcategory. Clinical exome sequencing was superior than aCGH for all cases except for isolated ASD, with no additional cases solved by NGS. Globally, clinical exome sequencing solved 20% of cases (versus 5.7% by aCGH) and the diagnostic yield was highest for all forms of GDD/ID and lowest for Other NDDs (7.1% versus 1.4% by aCGH) and ASD (6.1% versus 3% by aCGH). In the majority of cases, diagnostic yield was higher in the phenotype subcategories than in the mother category. These results suggest that NGS could be used as a first-tier test in the diagnostic algorithm of all NDDs followed by aCGH when necessary.

scholarly journals Diagnostic yield from routine metabolic screening tests in evaluation of global developmental delay and intellectual disability

2020 ◽  
Author(s):  
Hilary Vallance ◽  
Graham Sinclair ◽  
Bojana Rakic ◽  
Sylvia Stockler-Ipsiroglu
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
Diagnostic Yield ◽  
Language Delay ◽  
Screening Tests ◽  
Global Developmental Delay ◽  
Test Panel ◽  
Community Based ◽  
Organic Acidurias ◽  
Red Flag

Abstract Global developmental delay and intellectual disability (GDD/ID) affect 3% of the paediatric population. Although inborn errors of metabolism (IEM) are not a common cause of GDD/ID, early therapeutic intervention can improve neurodevelopmental manifestations. In 2012, a first-tier test panel, including specialized metabolic and routine chemistry tests, was piloted to community-based paediatricians in British Columbia with aims to achieve earlier diagnosis of treatable IEM. Objective The aim of this retrospective review was to evaluate the diagnostic yield from these first-tier tests in the 7 years before (2006 to 2012) and after (2013 to 2019) implementation at the community paediatrician level. Results Prior and postimplementation diagnostic yield of an IEM from first-tier metabolic testing was 9 out of 986 (0.91%) and 11 out of 4,345 children (0.25%), respectively. Disorders of creatine metabolism and organic acidurias were the most frequently established diagnoses in both time periods. No diagnoses were established through acylcarnitine copper/ceruloplasmin, lactate, or ammonia testing. Twenty out of 24 patients had specific neurological or other red flag signs in addition to GDD/ID. Four boys diagnosed with an x-linked creatine transporter defect (CTD) had speech-language delay as the most prominent finding. Conclusions The expansion of first-tier metabolic testing to community-based paediatricians in BC did not yield an increase in IEM diagnoses. A modified first-tier test panel should be offered to patients with GDD/ID, neurologic, and/or red flag signs. Urine creatine testing in boys with speech-language delay warrants consideration to detect CTD.

scholarly journals Genetic Analysis of Children With Unexplained Developmental Delay and/or Intellectual Disability by Whole-Exome Sequencing

2021 ◽  
Vol 12 ◽  
Author(s):  
Jingjing Xiang ◽  
Yang Ding ◽  
Fei Yang ◽  
Ang Gao ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
Neurodevelopmental Disorders ◽  
Copy Number ◽  
Diagnostic Yield ◽  
Single Nucleotide ◽  
Whole Exome ◽  
Number Variation

Background: Whole-exome sequencing (WES) has been recommended as a first-tier clinical diagnostic test for individuals with neurodevelopmental disorders (NDDs). We aimed to identify the genetic causes of 17 children with developmental delay (DD) and/or intellectual disability (ID).Methods: WES and exome-based copy number variation (CNV) analysis were performed for 17 patients with unexplained DD/ID.Results: Single-nucleotide variant (SNV)/small insertion or deletion (Indel) analysis and exome-based CNV calling yielded an overall diagnostic rate of 58.8% (10/17), of which diagnostic SNVs/Indels accounted for 41.2% (7/17) and diagnostic CNVs accounted for 17.6% (3/17).Conclusion: Our findings expand the known mutation spectrum of genes related to DD/ID and indicate that exome-based CNV analysis could improve the diagnostic yield of patients with DD/ID.

scholarly journals Whole-exome sequencing in an individual with severe global developmental delay and intractable epilepsy identifies a novel, de novoGRIN2Amutation

Epilepsia ◽  
2014 ◽  
Vol 55 (7) ◽  
pp. e75-e79 ◽  
Author(s):  
Sunita Venkateswaran ◽  
Ken A. Myers ◽  
Amanda C. Smith ◽  
Chandree L. Beaulieu ◽  
Jeremy A. Schwartzentruber ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
Intractable Epilepsy ◽  
Global Developmental Delay ◽  
Whole Exome
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