RESUMO
Genome-wide association studies have discovered hundreds of associations between common genotypes and kidney function but cannot comprehensively investigate rare coding variants. Here, we apply a genotype imputation approach to whole exome sequencing data from the UK Biobank to increase sample size from 166,891 to 408,511. We detect 158 rare variants and 105 genes significantly associated with one or more of five kidney function traits, including genes not previously linked to kidney disease in humans. The imputation-powered findings derive support from clinical record-based kidney disease information, such as for a previously unreported splice allele in PKD2, and from functional studies of a previously unreported frameshift allele in CLDN10. This cost-efficient approach boosts statistical power to detect and characterize both known and novel disease susceptibility variants and genes, can be generalized to larger future studies, and generates a comprehensive resource ( https://ckdgen-ukbb.gm.eurac.edu/ ) to direct experimental and clinical studies of kidney disease.
Assuntos
Exoma , Estudo de Associação Genômica Ampla , Humanos , Exoma/genética , Bancos de Espécimes Biológicos , Rim , Reino Unido , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Cholesteatoma is a rare progressive disease of the middle ear. Most cases are sporadic, but some patients report a positive family history. Identifying functionally important gene variants associated with this disease has the potential to uncover the molecular basis of cholesteatoma pathology with implications for disease prevention, surveillance, or management. We performed an observational WES study of 21 individuals treated for cholesteatoma who were recruited from ten multiply affected families. These family studies were complemented with gene-level mutational burden analysis. We also applied functional enrichment analyses to identify shared properties and pathways for candidate genes and their products. Filtered data collected from pairs and trios of participants within the ten families revealed 398 rare, loss of function (LOF) variants co-segregating with cholesteatoma in 389 genes. We identified six genes DENND2C, DNAH7, NBEAL1, NEB, PRRC2C, and SHC2, for which we found LOF variants in two or more families. The parallel gene-level analysis of mutation burden identified a significant mutation burden for the genes in the DNAH gene family, which encode products involved in ciliary structure. Functional enrichment analyses identified common pathways for the candidate genes which included GTPase regulator activity, calcium ion binding, and degradation of the extracellular matrix. The number of candidate genes identified and the locus heterogeneity that we describe within and between multiply affected families suggest that the genetic architecture for familial cholesteatoma is complex.
Assuntos
Exoma , Modalidades de Fisioterapia , Humanos , Sequenciamento do Exoma , Linhagem , Exoma/genética , Predisposição Genética para DoençaRESUMO
Hereditary deafness is one of the most common sensory disorders in humans, and exhibits high genetic heterogeneity. At present, the commonly used molecular diagnostic methods include gene chip, Sanger sequencing, targeted enrichment sequencing, and whole-exome sequencing, with diagnosis rates reaching 33.5%-56.67%. However, there are still a considerable number of patients who can not get a timely and definitive molecular diagnosis. Furthermore, considering the economic burden on patients' families and the relatively high cost of whole-exome or whole-genome sequencing, it is vital to provide stepwise strategies combining multiple detection methods according to the phenotypes of patients. In this review, we evaluate and discuss the utility of molecular diagnosis and the application of stepwise testing strategies in hereditary deafness to provide reference for the selection of diagnostic strategies.
Assuntos
Surdez , Humanos , Surdez/diagnóstico , Surdez/genética , Sequenciamento Completo do Genoma , Exoma , Fenótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Linhagem , Testes Genéticos , MutaçãoRESUMO
Cerebral arachnoid cysts (ACs) are one of the most common and poorly understood types of developmental brain lesion. To begin to elucidate AC pathogenesis, we performed an integrated analysis of 617 patient-parent (trio) exomes, 152,898 human brain and mouse meningeal single-cell RNA sequencing transcriptomes and natural language processing data of patient medical records. We found that damaging de novo variants (DNVs) were highly enriched in patients with ACs compared with healthy individuals (P = 1.57 × 10-33). Seven genes harbored an exome-wide significant DNV burden. AC-associated genes were enriched for chromatin modifiers and converged in midgestational transcription networks essential for neural and meningeal development. Unsupervised clustering of patient phenotypes identified four AC subtypes and clinical severity correlated with the presence of a damaging DNV. These data provide insights into the coordinated regulation of brain and meningeal development and implicate epigenomic dysregulation due to DNVs in AC pathogenesis. Our results provide a preliminary indication that, in the appropriate clinical context, ACs may be considered radiographic harbingers of neurodevelopmental pathology warranting genetic testing and neurobehavioral follow-up. These data highlight the utility of a systems-level, multiomics approach to elucidate sporadic structural brain disease.
Assuntos
Cistos Aracnóideos , Multiômica , Humanos , Animais , Camundongos , Cistos Aracnóideos/diagnóstico por imagem , Cistos Aracnóideos/genética , Encéfalo/diagnóstico por imagem , Exoma/genética , Testes GenéticosRESUMO
Inherited retinal diseases (IRDs) are a diverse set of visual disorders that collectively represent a major cause of early-onset blindness. With the reduction in sequencing costs in recent years, whole-genome sequencing (WGS) is being used more frequently, particularly when targeted gene panels and whole-exome sequencing (WES) fail to detect pathogenic mutations in patients. In this study, we performed mutation screens using WGS for a cohort of 311 IRD patients whose mutations were undetermined. A total of nine putative pathogenic mutations in six IRD patients were identified, including six novel mutations. Among them, four were deep intronic mutations that affected mRNA splicing, while the other five affected protein-coding sequences. Our results suggested that the rate of resolution of unsolved cases via targeted gene panels and WES can be further enhanced with WGS; however, the overall improvement may be limited.
Assuntos
Exoma , Doenças Retinianas , Humanos , Doenças Retinianas/genética , Sequenciamento Completo do Genoma/métodos , Mutação , Sequenciamento do ExomaRESUMO
Background: The IL-12/IFN-γ axis pathways play a vital role in the control of intracellular pathogens such as Salmonella typhi. Objective: The study is aimed at using whole exome sequencing (WES) to screen out genetic defects in IL-12/IFN-γ axis in patients with recurrent typhoid fever. Methods: WES using next-generation sequencing was performed on a single patient diagnosed with recurrent typhoid fever. Following alignment and variant calling, exomes were screened for mutations in 25 genes that are involved in the IL-12/IFN-γ axis pathway. Each variant was assessed by using various bioinformatics mutational analysis tools such as SIFT, Polyphen2, LRT, MutationTaster, and MutationAssessor. Results: Out of 25 possible variations in the IL-12/IFN-γ axis genes, only 2 probable disease-causing mutations were identified. These variations were rare and include mutations in IL23R and ZNFX I. Other pathogenic mutations were found, but they were not considered likely to cause disease based on various mutation predictors. Conclusion: Applying WES to the patient with recurrent typhoid fever detects variants that are not much important as other genes in the IL-12/IFN-γ axis. Results of the current study suggest that a large population sizes would be needed to examine the functional relevance of IL-12/IFN-γ axis genes with recurrent typhoid fever.
Assuntos
Febre Tifoide , Humanos , Exoma/genética , Interferon gama/genética , Interleucina-12/genética , Mutação/genética , Análise de Sequência , Febre Tifoide/genética , RecidivaRESUMO
Purpose: To identify the molecular background of eyelid sebaceous gland carcinomas (SCs), we conducted the integrated whole-exome sequencing and transcriptome sequencing for eyelid SCs in this study. Methods: The genetic alterations were studied by whole-exome sequencing, and the messenger RNA expression was studied using Oxford Nanopore Technologies (ONT) in five paired fresh eyelid SC tissues and adjacent normal tissues. Integrated analysis of exome and transcriptomic information was conducted for filtering candidate driver genes. Protein-protein interaction (PPI) network of filtered candidate genes was analyzed by STRING. The protein expression was verified by immunohistochemistry in 29 eyelid SCs and 17 compared normal sebaceous gland tissues. Results: The average numbers of pathogenic somatic single-nucleotide variants (SNVs) and indels in eyelid SCs were 75 and 28, respectively. Tumor protein p53 (TP53), zinc finger protein 750 (ZNF750), filaggrin 2 (FLG2), valosin-containing protein (VCP), and zinc finger protein 717 (ZNF717) were recurrent mutated genes. A mean of 844 differentially expressed genes (DEGs) were upregulated, and 1401 DEGs were downregulated in SC samples. The intersection of DEG-based pathways and mutation-based pathways was mainly involved in microbial infection and inflammation, immunodeficiency, cancer, lipid metabolism, and the other pathways. The intersection of DEGs and mutated genes consisted of 55 genes, of which 15 genes formed a PPI network with 4 clusters. The PPI cluster composed of scavenger receptor class B member 1 (SCARB1), peroxisome proliferator-activated receptor γ (PPARG), peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A) was involved in cholesterol metabolism. The expression of SCARB1 protein was found to be increased, whereas that of PPARG protein was decreased in eyelid SCs compared to that in the normal sebaceous glands. Conclusions: Increased SCARB1 and decreased PPARG indicated that dysregulation of cholesterol metabolism might be involved in carcinogenesis of eyelid SCs. Translational Relevance: The malfunction in cholesterol metabolism might advance our knowledge of the carcinogenesis of eyelid SCs.
Assuntos
Carcinoma , Neoplasias Palpebrais , Humanos , Transcriptoma/genética , Exoma/genética , Glândulas Sebáceas/metabolismo , Glândulas Sebáceas/patologia , PPAR gama/genética , PPAR gama/metabolismo , Sequenciamento do Exoma , Neoplasias Palpebrais/genética , Neoplasias Palpebrais/metabolismo , Neoplasias Palpebrais/patologia , Pálpebras , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Metabolismo dos Lipídeos/genética , Carcinoma/genética , Carcinoma/metabolismo , Carcinoma/patologia , Colesterol/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Cohort-wide sequencing studies have revealed that the largest category of variants is those deemed 'rare', even for the subset located in coding regions (99% of known coding variants are seen in less than 1% of the population. Associative methods give some understanding how rare genetic variants influence disease and organism-level phenotypes. But here we show that additional discoveries can be made through a knowledge-based approach using protein domains and ontologies (function and phenotype) that considers all coding variants regardless of allele frequency. We describe an ab initio, genetics-first method making molecular knowledge-based interpretations for exome-wide non-synonymous variants for phenotypes at the organism and cellular level. By using this reverse approach, we identify plausible genetic causes for developmental disorders that have eluded other established methods and present molecular hypotheses for the causal genetics of 40 phenotypes generated from a direct-to-consumer genotype cohort. This system offers a chance to extract further discovery from genetic data after standard tools have been applied.
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Exoma , Predisposição Genética para Doença , Humanos , Fenótipo , Genótipo , Frequência do GeneRESUMO
There remain challenges in accurately identifying constitutional or germline copy number variants (gCNVs) based on whole-exome sequencing data that have implications for genetic diagnosis for 'rare undiagnosed disease' in the clinical setting. Although multiple algorithms have been proposed, a systematic comparison of these algorithms for calling gCNVs and analyzing inherited pattern have yet to be fully conducted. Therefore, we empirically compared seven exome-based algorithms, including XHMM, CLAMMS, CODEX2, ExomeDepth, DECoN, CN.MOPS, and GATK gCNV, for calling gCNVs in 151 individuals from 44 pedigrees, together with the gold standard of genotyping-derived gCNVs in the same cohort for the performance assessment. These algorithms demonstrated varied powers in identifying gCNVs, although the distribution of gCNVs size was similar. The number of shared gCNVs across these algorithms was limited (e.g., only four gCNVs shared among seven algorithms); however, several algorithms showed varying degrees of consistency (e.g., 1,843 gCNVs shared between DECoN and ExomeDepth). CLAMMS and CODEX2 outperformed the remaining algorithms according to a relatively higher F-score (i.e., 0.145 and 0.152, respectively). In addition, these algorithms exhibited different Mendelian inconsistencies of gCNVs and significant challenges remained in inheritance pattern analysis. In conclusion, selecting good algorithms may have important implications in gCNVs-based inheritance pattern analysis for family-based studies.
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Algoritmos , Variações do Número de Cópias de DNA , Humanos , Sequenciamento do Exoma , Exoma , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
Dietary nutrient composition is essential for shaping important fitness traits and behaviours. Many organisms are protein limited, and for Drosophila melanogaster this limitation manifests at the level of the single most limiting essential Amino Acid (AA) in the diet. The identity of this AA and its effects on female fecundity is readily predictable by a procedure called exome matching in which the sum of AAs encoded by a consumer's exome is used to predict the relative proportion of AAs required in its diet. However, the exome matching calculation does not weight AA contributions to the overall profile by protein size or expression. Here, we update the exome matching calculation to include these weightings. Surprisingly, although nearly half of the transcriptome is differentially expressed when comparing male and female flies, we found that creating transcriptome-weighted exome matched diets for each sex did not enhance their fecundity over that supported by exome matching alone. These data indicate that while organisms may require different amounts of dietary protein across conditions, the relative proportion of the constituent AAs remains constant. Interestingly, we also found that exome matched AA profiles are generally conserved across taxa and that the composition of these profiles might be explained by energetic and elemental limitations on microbial AA synthesis. Thus, it appears that ecological constraints amongst autotrophs shape the relative proportion of AAs that are available across trophic levels and that this constrains biomass composition.
Assuntos
Aminoácidos , Cadeia Alimentar , Animais , Masculino , Feminino , Aminoácidos/metabolismo , Drosophila melanogaster/metabolismo , Dieta , ExomaRESUMO
Aicardi-Goutières syndrome (AGS) is a progressive multisystem disorder including encephalopathy with significant impacts on intellectual and physical abilities. An early diagnosis is becoming ever more crucial, as targeted therapies are emerging. A deep understanding of the molecular heterogeneity of AGS can help guide the early diagnosis and clinical management of patients, and inform recurrence risks. Here, we detail the diagnostic odyssey of a patient with an early presentation of AGS. Exome and genome sequencing detected an intronic RNASEH2B variant missed in a conventional leukodystrophy NGS gene panel. RNA studies demonstrated that a c.322-17 A > G variant affected splicing and caused 16-nucleotide intronic retention in the RNASEH2B transcript, introducing an out-of-frame early termination codon. RNASEH2B expression in the patient's blood was reduced when compared to controls. Our study highlights the pathogenicity of this intronic variant and the importance of its inclusion in variant assessment.
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Doenças Autoimunes do Sistema Nervoso , Malformações do Sistema Nervoso , Humanos , Mutação , Doenças Autoimunes do Sistema Nervoso/genética , Malformações do Sistema Nervoso/genética , ExomaRESUMO
Pathogenic variants in both mitochondrial and nuclear genes contribute to the clinical and genetic heterogeneity of mitochondrial diseases. There are now pathogenic variants in over 300 nuclear genes linked to human mitochondrial diseases. Nonetheless, diagnosing mitochondrial disease with a genetic outcome remains challenging. However, there are now many strategies that help us to pinpoint causative variants in patients with mitochondrial disease. This chapter describes some of the approaches and recent advancements in gene/variant prioritization using whole-exome sequencing (WES).
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Exoma , Doenças Mitocondriais , Humanos , Genômica , Doenças Mitocondriais/genética , Sequenciamento do Exoma , Núcleo CelularRESUMO
Proxy phenotypes allow for the utilization of genetic data from large population cohorts to analyze late-onset diseases by using parental diagnoses as a proxy for genetic disease risk. Proxy phenotypes based on parental diagnosis status have been used in previous studies to identify common variants associated with Alzheimer's disease. As of yet, proxy phenotypes have not been used to identify genes associated with Alzheimer's disease through rare variants. Here we show that a proxy Alzheimer's disease/dementia phenotype can capture known Alzheimer's disease risk genes through rare variant aggregation. We generated a proxy Alzheimer's disease/dementia phenotype for 148,508 unrelated individuals of European ancestry in the UK biobank in order to perform exome-wide rare variant aggregation analyses to identify genes associated with proxy Alzheimer's disease/dementia. We identified four genes significantly associated with the proxy phenotype, three of which were significantly associated with proxy Alzheimer's disease/dementia in an independent replication cohort consisting of 197,506 unrelated individuals of European ancestry in the UK biobank. All three of the replicated genes have been previously associated with clinically diagnosed Alzheimer's disease (SORL1, TREM2, and TOMM40/APOE). We show that proxy Alzheimer's disease/dementia can be used to identify genes associated with Alzheimer's disease through rare variant aggregation.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/genética , Variação Genética , Exoma , Estudo de Associação Genômica Ampla , Fatores de Risco , Predisposição Genética para Doença , Proteínas Relacionadas a Receptor de LDL/genética , Proteínas de Membrana Transportadoras/genéticaRESUMO
Both common and rare genetic variants influence complex traits and common diseases. Genome-wide association studies have identified thousands of common-variant associations, and more recently, large-scale exome sequencing studies have identified rare-variant associations in hundreds of genes1-3. However, rare-variant genetic architecture is not well characterized, and the relationship between common-variant and rare-variant architecture is unclear4. Here we quantify the heritability explained by the gene-wise burden of rare coding variants across 22 common traits and diseases in 394,783 UK Biobank exomes5. Rare coding variants (allele frequency < 1 × 10-3) explain 1.3% (s.e. = 0.03%) of phenotypic variance on average-much less than common variants-and most burden heritability is explained by ultrarare loss-of-function variants (allele frequency < 1 × 10-5). Common and rare variants implicate the same cell types, with similar enrichments, and they have pleiotropic effects on the same pairs of traits, with similar genetic correlations. They partially colocalize at individual genes and loci, but not to the same extent: burden heritability is strongly concentrated in significant genes, while common-variant heritability is more polygenic, and burden heritability is also more strongly concentrated in constrained genes. Finally, we find that burden heritability for schizophrenia and bipolar disorder6,7 is approximately 2%. Our results indicate that rare coding variants will implicate a tractable number of large-effect genes, that common and rare associations are mechanistically convergent, and that rare coding variants will contribute only modestly to missing heritability and population risk stratification.
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Exoma , Frequência do Gene , Variação Genética , Herança Multifatorial , Humanos , Exoma/genética , Variação Genética/genética , Estudo de Associação Genômica Ampla , Herança Multifatorial/genética , Fatores de Risco , Reino Unido , Loci Gênicos/genética , Esquizofrenia/genética , Transtorno Bipolar/genéticaRESUMO
Importance: VEXAS (vacuoles, E1-ubiquitin-activating enzyme, X-linked, autoinflammatory, somatic) syndrome is a disease with rheumatologic and hematologic features caused by somatic variants in UBA1. Pathogenic variants are associated with a broad spectrum of clinical manifestations. Knowledge of prevalence, penetrance, and clinical characteristics of this disease have been limited by ascertainment biases based on known phenotypes. Objective: To determine the prevalence of pathogenic variants in UBA1 and associated clinical manifestations in an unselected population using a genomic ascertainment approach. Design, Setting, and Participants: This retrospective observational study evaluated UBA1 variants in exome data from 163â¯096 participants within the Geisinger MyCode Community Health Initiative. Clinical phenotypes were determined from Geisinger electronic health record data from January 1, 1996, to January 1, 2022. Exposures: Exome sequencing was performed. Main Outcomes and Measures: Outcome measures included prevalence of somatic UBA1 variation; presence of rheumatologic, hematologic, pulmonary, dermatologic, and other findings in individuals with somatic UBA1 variation on review of the electronic health record; review of laboratory data; bone marrow biopsy pathology analysis; and in vitro enzymatic assays. Results: In 163â¯096 participants (mean age, 52.8 years; 94% White; 61% women), 11 individuals harbored likely somatic variants at known pathogenic UBA1 positions, with 11 of 11 (100%) having clinical manifestations consistent with VEXAS syndrome (9 male, 2 female). A total of 5 of 11 individuals (45%) did not meet criteria for rheumatologic and/or hematologic diagnoses previously associated with VEXAS syndrome; however, all individuals had anemia (hemoglobin: mean, 7.8 g/dL; median, 7.5 g/dL), which was mostly macrocytic (10/11 [91%]) with concomitant thrombocytopenia (10/11 [91%]). Among the 11 patients identified, there was a pathogenic variant in 1 male participant prior to onset of VEXAS-related signs or symptoms and 2 female participants had disease with heterozygous variants. A previously unreported UBA1 variant (c.1861A>T; p.Ser621Cys) was found in a symptomatic patient, with in vitro data supporting a catalytic defect and pathogenicity. Together, disease-causing UBA1 variants were found in 1 in 13â¯591 unrelated individuals (95% CI, 1:7775-1:23â¯758), 1 in 4269 men older than 50 years (95% CI, 1:2319-1:7859), and 1 in 26â¯238 women older than 50 years (95% CI, 1:7196-1:147â¯669). Conclusions and Relevance: This study provides an estimate of the prevalence and a description of the clinical manifestations of UBA1 variants associated with VEXAS syndrome within a single regional health system in the US. Additional studies are needed in unselected and genetically diverse populations to better define general population prevalence and phenotypic spectrum.
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Síndromes Mielodisplásicas , Dermatopatias Genéticas , Enzimas Ativadoras de Ubiquitina , Feminino , Humanos , Masculino , Biópsia , Registros Eletrônicos de Saúde , Prevalência , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/epidemiologia , Síndromes Mielodisplásicas/genética , Enzimas Ativadoras de Ubiquitina/genética , Mutação , Estudos Retrospectivos , Exoma , Pessoa de Meia-Idade , Dermatopatias Genéticas/complicações , Dermatopatias Genéticas/diagnóstico , Dermatopatias Genéticas/epidemiologia , Dermatopatias Genéticas/genética , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Biallelic pathogenic variants in AIMP1 gene cause hypomyelinating leukodystrophy type 3, a severe neurodegenerative disorder with early onset characterized by microcephaly, axial hypotonia, epilepsy, spasticity, and developmental delay. METHODS: Clinical exome sequence was performed on patient's DNA and Sanger sequencing was used to confirm the candidate variant. To better characterize the effect of the genetic variant, functional analysis based on Sanger sequencing of the proband's complementary DNA (cDNA) was performed. RESULTS: We report a case of 2-year-old girl with microcephaly, significant global developmental delay, refractory epilepsy, flaccid paralysis, hypomyelination, leukodystrophy, and cerebral atrophy on brain magnetic resonance imaging (MRI). Clinical exome sequencing revealed a novel splice site variant c.603 + 1G > A in homozygosity in the AIMP1 gene. Studies on patient's cDNA showed that the variant disrupts the canonical donor splice site of intron 5, with the recognition of a cryptic splice site within exon 5, leading to the skipping of the last 24 nucleotides of this exon together with the flanking intron. This alteration is predicted to cause an in-frame deletion of eight amino acids (p.Val194_Gln201del) belonging to the tRNA-biding domain of the protein. CONCLUSION: To the best of our knowledge, this is the first report of a splice site variant in the AIMP1 gene causing hypomyelinating leukodystrophy. The description of this patient not only expands the mutational spectrum of AIMP1 but also provides deeper insights on genotype-phenotype correlation by comparing the clinical features of our patient with previously reported affected individuals.
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Microcefalia , Humanos , Microcefalia/genética , DNA Complementar , Mutação , Encéfalo/patologia , ExomaRESUMO
Exome sequencing (ES) and genome sequencing (GS) have radically transformed the diagnostic approach to undiagnosed rare/ultrarare Mendelian diseases. Next-generation sequencing (NGS), the technology integral for ES, GS, and most large (100+) gene panels, has enabled previously unimaginable diagnoses, changes in medical management, new treatments, and accurate reproductive risk assessments for patients, as well as new disease gene discoveries. Yet, challenges remain, as most individuals remain undiagnosed with current NGS. Improved NGS technology has resulted in long-read sequencing, which may resolve diagnoses in some patients who do not obtain a diagnosis with current short-read ES and GS, but its effectiveness is unclear, and it is expensive. Other challenges that persist include the resolution of variants of uncertain significance, the urgent need for patients with ultrarare disorders to have access to therapeutics, the need for equity in patient access to NGS-based testing, and the study of ethical concerns. However, the outlook for undiagnosed disease resolution is bright, due to continual advancements in the field.
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Exoma , Doenças Raras , Humanos , Sequenciamento do Exoma , Exoma/genética , Doenças Raras/diagnóstico , Doenças Raras/genética , Sequenciamento de Nucleotídeos em Larga Escala , Testes Genéticos/métodosRESUMO
BACKGROUND: Rare diseases collectively impose a significant burden on healthcare systems, especially in underserved regions, like the Middle East, which lack access to genomic diagnostic services and the associated personalized management plans. METHODS: We established a clinical genomics and genetic counseling facility, within a multidisciplinary tertiary pediatric center, in the United Arab Emirates to locally diagnose and manage patients with rare diseases. Clinical genomic investigations included exome-based sequencing, chromosomal microarrays, and/or targeted testing. We assessed the diagnostic yield and implications for clinical management among this population. Variables were compared using the Fisher exact test. Tests were 2-tailed, and P < .05 was considered statistically significant. RESULTS: We present data on 1000 patients with rare diseases (46.2% females; average age, 4.6 years) representing 47 countries primarily from the Arabian Peninsula, the Levant, Africa, and Asia. The cumulative diagnostic yield was 32.5% (95% CI, 29.7-35.5%) and was higher for genomic sequencing-based testing than chromosomal microarrays (37.9% versus 17.2%, P = 0.0001) across all indications, consistent with the higher burden of single gene disorders. Of the 221 Mendelian disorders identified in this cohort, the majority (N = 184) were encountered only once, and those with recessive inheritance accounted for ~ 62% of sequencing diagnoses. Of patients with positive genetic findings (N = 325), 67.7% were less than 5 years of age, and 60% were offered modified management and/or intervention plans. Interestingly, 24% of patients with positive genetic findings received delayed diagnoses (average age, 12.4 years; range 7-37 years), most likely due to a lack of access to genomic investigations in this region. One such genetic finding ended a 15-year-long diagnostic odyssey, leading to a life-threatening diagnosis in one patient, who was then successfully treated using an experimental allogenic bone marrow transplant. Finally, we present cases with candidate genes within regions of homozygosity, likely underlying novel recessive disorders. CONCLUSIONS: Early access to genomic diagnostics for patients with suspected rare disorders in the Middle East is likely to improve clinical outcomes while driving gene discovery in this genetically underrepresented population.
Assuntos
Testes Genéticos , Doenças Raras , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Exoma , Genômica , Oriente Médio , Doenças Raras/diagnóstico , Doenças Raras/genética , Doenças Raras/terapia , Adolescente , Adulto Jovem , AdultoRESUMO
OBJECTIVES: Genetics of epilepsy are highly heterogeneous and complex. Lesions detected involve genes encoding various types of channels, transcription factors, and other proteins implicated in numerous cellular processes, such as synaptogenesis. Consequently, a wide spectrum of clinical presentations and overlapping phenotypes hinders differential diagnosis and highlights the need for molecular investigations toward delineation of underlying mechanisms and final diagnosis. Characterization of defects may also contribute valuable data on genetic landscapes and networks implicated in epileptogenesis. METHODS: This study reports on genetic findings from exome sequencing (ES) data of 107 patients with variable types of seizures, with or without additional symptoms, in the context of neurodevelopmental disorders. RESULTS: Multidisciplinary evaluation of ES, including ancillary detection of copy number variants (CNVs) with the ExomeDepth tool, supported a definite diagnosis in 59.8% of the patients, reflecting one of the highest diagnostic yields in epilepsy. CONCLUSION: Emerging advances of next-generation technologies and 'in silico' analysis tools offer the possibility to simultaneously detect several types of variations. Wide assessment of variable findings, specifically those found to be novel and least expected, reflects the ever-evolving genetic landscape of seizure development, potentially beneficial for increased opportunities for trial recruitment and enrollment, and optimized, even personalized, medical management.